//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://www.antigrain.com
//----------------------------------------------------------------------------
//
// Adaptation for high precision colors has been sponsored by
// Liberty Technology Systems, Inc., visit http://lib-sys.com
//
// Liberty Technology Systems, Inc. is the provider of
// PostScript and PDF technology for software developers.
//
//----------------------------------------------------------------------------

#ifndef AGG_PIXFMT_RGBA_INCLUDED
#define AGG_PIXFMT_RGBA_INCLUDED

#include <mapnik/config.hpp>
#include <cstring>
#include <cmath>
#include "agg_basics.h"
#include "agg_color_rgba.h"
#include "agg_rendering_buffer.h"

namespace agg
{

//=========================================================multiplier_rgba
template<class ColorT, class Order> struct multiplier_rgba
{
    typedef typename ColorT::value_type value_type;
    typedef typename ColorT::calc_type calc_type;

    //--------------------------------------------------------------------
    static AGG_INLINE void premultiply(value_type* p)
    {
        calc_type a = p[Order::A];
        if(a < ColorT::base_mask)
        {
            if(a == 0)
            {
                p[Order::R] = p[Order::G] = p[Order::B] = 0;
                return;
            }
            p[Order::R] = value_type((p[Order::R] * a + ColorT::base_mask) >> ColorT::base_shift);
            p[Order::G] = value_type((p[Order::G] * a + ColorT::base_mask) >> ColorT::base_shift);
            p[Order::B] = value_type((p[Order::B] * a + ColorT::base_mask) >> ColorT::base_shift);
        }
    }


    //--------------------------------------------------------------------
    static AGG_INLINE void demultiply(value_type* p)
    {
        calc_type a = p[Order::A];
        if(a < ColorT::base_mask)
        {
            if(a == 0)
            {
                p[Order::R] = p[Order::G] = p[Order::B] = 0;
                return;
            }
            calc_type r = (calc_type(p[Order::R]) * ColorT::base_mask) / a;
            calc_type g = (calc_type(p[Order::G]) * ColorT::base_mask) / a;
            calc_type b = (calc_type(p[Order::B]) * ColorT::base_mask) / a;
            p[Order::R] = value_type((r > ColorT::base_mask) ? ColorT::base_mask : r);
            p[Order::G] = value_type((g > ColorT::base_mask) ? ColorT::base_mask : g);
            p[Order::B] = value_type((b > ColorT::base_mask) ? ColorT::base_mask : b);
        }
    }
};

//=====================================================apply_gamma_dir_rgba
template<class ColorT, class Order, class GammaLut> class apply_gamma_dir_rgba
{
public:
    typedef typename ColorT::value_type value_type;

    apply_gamma_dir_rgba(const GammaLut& gamma) : m_gamma(gamma) {}

    AGG_INLINE void operator () (value_type* p)
    {
        p[Order::R] = m_gamma.dir(p[Order::R]);
        p[Order::G] = m_gamma.dir(p[Order::G]);
        p[Order::B] = m_gamma.dir(p[Order::B]);
    }

private:
    const GammaLut& m_gamma;
};

//=====================================================apply_gamma_inv_rgba
template<class ColorT, class Order, class GammaLut> class apply_gamma_inv_rgba
{
public:
    typedef typename ColorT::value_type value_type;

    apply_gamma_inv_rgba(const GammaLut& gamma) : m_gamma(gamma) {}

    AGG_INLINE void operator () (value_type* p)
    {
        p[Order::R] = m_gamma.inv(p[Order::R]);
        p[Order::G] = m_gamma.inv(p[Order::G]);
        p[Order::B] = m_gamma.inv(p[Order::B]);
    }

private:
    const GammaLut& m_gamma;
};

//=============================================================blender_rgba
template<class ColorT, class Order> struct blender_rgba
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    //--------------------------------------------------------------------
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned alpha,
                                     unsigned /*cover*/=0)
    {
        calc_type r = p[Order::R];
        calc_type g = p[Order::G];
        calc_type b = p[Order::B];
        calc_type a = p[Order::A];
        p[Order::R] = (value_type)(((cr - r) * alpha + (r << base_shift)) >> base_shift);
        p[Order::G] = (value_type)(((cg - g) * alpha + (g << base_shift)) >> base_shift);
        p[Order::B] = (value_type)(((cb - b) * alpha + (b << base_shift)) >> base_shift);
        p[Order::A] = (value_type)((alpha + a) - ((alpha * a + base_mask) >> base_shift));
    }
};

//=========================================================blender_rgba_pre
template<class ColorT, class Order> struct blender_rgba_pre
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    //--------------------------------------------------------------------
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned alpha,
                                     unsigned cover)
    {
        alpha = color_type::base_mask - alpha;
        cover = (cover + 1) << (base_shift - 8);
        p[Order::R] = (value_type)((p[Order::R] * alpha + cr * cover) >> base_shift);
        p[Order::G] = (value_type)((p[Order::G] * alpha + cg * cover) >> base_shift);
        p[Order::B] = (value_type)((p[Order::B] * alpha + cb * cover) >> base_shift);
        p[Order::A] = (value_type)(base_mask - ((alpha * (base_mask - p[Order::A])) >> base_shift));
    }

    //--------------------------------------------------------------------
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned alpha)
    {
        alpha = color_type::base_mask - alpha;
        p[Order::R] = (value_type)(((p[Order::R] * alpha) >> base_shift) + cr);
        p[Order::G] = (value_type)(((p[Order::G] * alpha) >> base_shift) + cg);
        p[Order::B] = (value_type)(((p[Order::B] * alpha) >> base_shift) + cb);
        p[Order::A] = (value_type)(base_mask - ((alpha * (base_mask - p[Order::A])) >> base_shift));
    }
};

//======================================================blender_rgba_plain
template<class ColorT, class Order> struct blender_rgba_plain
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e { base_shift = color_type::base_shift };

    //--------------------------------------------------------------------
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned alpha,
                                     unsigned /*cover*/=0)
    {
        if(alpha == 0) return;
        calc_type a = p[Order::A];
        calc_type r = p[Order::R] * a;
        calc_type g = p[Order::G] * a;
        calc_type b = p[Order::B] * a;
        a = ((alpha + a) << base_shift) - alpha * a;
        p[Order::A] = (value_type)(a >> base_shift);
        p[Order::R] = (value_type)((((cr << base_shift) - r) * alpha + (r << base_shift)) / a);
        p[Order::G] = (value_type)((((cg << base_shift) - g) * alpha + (g << base_shift)) / a);
        p[Order::B] = (value_type)((((cb << base_shift) - b) * alpha + (b << base_shift)) / a);
    }
};











//=========================================================comp_op_rgba_clear
template<class ColorT, class Order> struct comp_op_rgba_clear
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned, unsigned, unsigned, unsigned,
                                     unsigned cover)
    {
        if(cover < 255)
        {
            cover = 255 - cover;
            p[Order::R] = (value_type)((p[Order::R] * cover + 255) >> 8);
            p[Order::G] = (value_type)((p[Order::G] * cover + 255) >> 8);
            p[Order::B] = (value_type)((p[Order::B] * cover + 255) >> 8);
            p[Order::A] = (value_type)((p[Order::A] * cover + 255) >> 8);
        }
        else
        {
            p[0] = p[1] = p[2] = p[3] = 0;
        }
    }
};

//===========================================================comp_op_rgba_src
template<class ColorT, class Order> struct comp_op_rgba_src
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            unsigned alpha = 255 - cover;
            p[Order::R] = (value_type)(((p[Order::R] * alpha + 255) >> 8) + ((sr * cover + 255) >> 8));
            p[Order::G] = (value_type)(((p[Order::G] * alpha + 255) >> 8) + ((sg * cover + 255) >> 8));
            p[Order::B] = (value_type)(((p[Order::B] * alpha + 255) >> 8) + ((sb * cover + 255) >> 8));
            p[Order::A] = (value_type)(((p[Order::A] * alpha + 255) >> 8) + ((sa * cover + 255) >> 8));
        }
        else
        {
            p[Order::R] = sr;
            p[Order::G] = sg;
            p[Order::B] = sb;
            p[Order::A] = sa;
        }
    }
};

//===========================================================comp_op_rgba_dst
template<class ColorT, class Order> struct comp_op_rgba_dst
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;

    static AGG_INLINE void blend_pix(value_type*,
                                     unsigned, unsigned, unsigned,
                                     unsigned, unsigned)
    {
    }
};

//======================================================comp_op_rgba_src_over
template<class ColorT, class Order> struct comp_op_rgba_src_over
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    //   Dca' = Sca + Dca.(1 - Sa)
    //   Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        calc_type s1a = base_mask - sa;
        p[Order::R] = (value_type)(sr + ((p[Order::R] * s1a + base_mask) >> base_shift));
        p[Order::G] = (value_type)(sg + ((p[Order::G] * s1a + base_mask) >> base_shift));
        p[Order::B] = (value_type)(sb + ((p[Order::B] * s1a + base_mask) >> base_shift));
        p[Order::A] = (value_type)(sa + ((p[Order::A] * s1a + base_mask) >> base_shift));
    }
};

//======================================================comp_op_rgba_dst_over
template<class ColorT, class Order> struct comp_op_rgba_dst_over
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Dca + Sca.(1 - Da)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        calc_type d1a = base_mask - p[Order::A];
        p[Order::R] = (value_type)(p[Order::R] + ((sr * d1a + base_mask) >> base_shift));
        p[Order::G] = (value_type)(p[Order::G] + ((sg * d1a + base_mask) >> base_shift));
        p[Order::B] = (value_type)(p[Order::B] + ((sb * d1a + base_mask) >> base_shift));
        p[Order::A] = (value_type)(p[Order::A] + ((sa * d1a + base_mask) >> base_shift));
    }
};

//======================================================comp_op_rgba_src_in
template<class ColorT, class Order> struct comp_op_rgba_src_in
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca.Da
    // Da'  = Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        calc_type da = p[Order::A];
        if(cover < 255)
        {
            unsigned alpha = 255 - cover;
            p[Order::R] = (value_type)(((p[Order::R] * alpha + 255) >> 8) + ((((sr * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::G] = (value_type)(((p[Order::G] * alpha + 255) >> 8) + ((((sg * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::B] = (value_type)(((p[Order::B] * alpha + 255) >> 8) + ((((sb * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::A] = (value_type)(((p[Order::A] * alpha + 255) >> 8) + ((((sa * da + base_mask) >> base_shift) * cover + 255) >> 8));
        }
        else
        {
            p[Order::R] = (value_type)((sr * da + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sg * da + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sb * da + base_mask) >> base_shift);
            p[Order::A] = (value_type)((sa * da + base_mask) >> base_shift);
        }
    }
};

//======================================================comp_op_rgba_dst_in
template<class ColorT, class Order> struct comp_op_rgba_dst_in
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Dca.Sa
    // Da'  = Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned, unsigned, unsigned,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sa = base_mask - ((cover * (base_mask - sa) + 255) >> 8);
        }
        p[Order::R] = (value_type)((p[Order::R] * sa + base_mask) >> base_shift);
        p[Order::G] = (value_type)((p[Order::G] * sa + base_mask) >> base_shift);
        p[Order::B] = (value_type)((p[Order::B] * sa + base_mask) >> base_shift);
        p[Order::A] = (value_type)((p[Order::A] * sa + base_mask) >> base_shift);
    }
};

//======================================================comp_op_rgba_src_out
template<class ColorT, class Order> struct comp_op_rgba_src_out
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca.(1 - Da)
    // Da'  = Sa.(1 - Da)
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        calc_type da = base_mask - p[Order::A];
        if(cover < 255)
        {
            unsigned alpha = 255 - cover;
            p[Order::R] = (value_type)(((p[Order::R] * alpha + 255) >> 8) + ((((sr * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::G] = (value_type)(((p[Order::G] * alpha + 255) >> 8) + ((((sg * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::B] = (value_type)(((p[Order::B] * alpha + 255) >> 8) + ((((sb * da + base_mask) >> base_shift) * cover + 255) >> 8));
            p[Order::A] = (value_type)(((p[Order::A] * alpha + 255) >> 8) + ((((sa * da + base_mask) >> base_shift) * cover + 255) >> 8));
        }
        else
        {
            p[Order::R] = (value_type)((sr * da + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sg * da + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sb * da + base_mask) >> base_shift);
            p[Order::A] = (value_type)((sa * da + base_mask) >> base_shift);
        }
    }
};

//======================================================comp_op_rgba_dst_out
template<class ColorT, class Order> struct comp_op_rgba_dst_out
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Dca.(1 - Sa)
    // Da'  = Da.(1 - Sa)
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned, unsigned, unsigned,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sa = (sa * cover + 255) >> 8;
        }
        sa = base_mask - sa;
        p[Order::R] = (value_type)((p[Order::R] * sa + base_shift) >> base_shift);
        p[Order::G] = (value_type)((p[Order::G] * sa + base_shift) >> base_shift);
        p[Order::B] = (value_type)((p[Order::B] * sa + base_shift) >> base_shift);
        p[Order::A] = (value_type)((p[Order::A] * sa + base_shift) >> base_shift);
    }
};

//=====================================================comp_op_rgba_src_atop
template<class ColorT, class Order> struct comp_op_rgba_src_atop
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca.Da + Dca.(1 - Sa)
    // Da'  = Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        calc_type da = p[Order::A];
        sa = base_mask - sa;
        p[Order::R] = (value_type)((sr * da + p[Order::R] * sa + base_mask) >> base_shift);
        p[Order::G] = (value_type)((sg * da + p[Order::G] * sa + base_mask) >> base_shift);
        p[Order::B] = (value_type)((sb * da + p[Order::B] * sa + base_mask) >> base_shift);
    }
};

//=====================================================comp_op_rgba_dst_atop
template<class ColorT, class Order> struct comp_op_rgba_dst_atop
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Dca.Sa + Sca.(1 - Da)
    // Da'  = Sa
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        calc_type da = base_mask - p[Order::A];
        if(cover < 255)
        {
            unsigned alpha = 255 - cover;
            sr = (p[Order::R] * sa + sr * da + base_mask) >> base_shift;
            sg = (p[Order::G] * sa + sg * da + base_mask) >> base_shift;
            sb = (p[Order::B] * sa + sb * da + base_mask) >> base_shift;
            p[Order::R] = (value_type)(((p[Order::R] * alpha + 255) >> 8) + ((sr * cover + 255) >> 8));
            p[Order::G] = (value_type)(((p[Order::G] * alpha + 255) >> 8) + ((sg * cover + 255) >> 8));
            p[Order::B] = (value_type)(((p[Order::B] * alpha + 255) >> 8) + ((sb * cover + 255) >> 8));
            p[Order::A] = (value_type)(((p[Order::A] * alpha + 255) >> 8) + ((sa * cover + 255) >> 8));

        }
        else
        {
            p[Order::R] = (value_type)((p[Order::R] * sa + sr * da + base_mask) >> base_shift);
            p[Order::G] = (value_type)((p[Order::G] * sa + sg * da + base_mask) >> base_shift);
            p[Order::B] = (value_type)((p[Order::B] * sa + sb * da + base_mask) >> base_shift);
            p[Order::A] = (value_type)sa;
        }
    }
};

//=========================================================comp_op_rgba_xor
template<class ColorT, class Order> struct comp_op_rgba_xor
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca.(1 - Da) + Dca.(1 - Sa)
    // Da'  = Sa + Da - 2.Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type s1a = base_mask - sa;
            calc_type d1a = base_mask - p[Order::A];
            p[Order::R] = (value_type)((p[Order::R] * s1a + sr * d1a + base_mask) >> base_shift);
            p[Order::G] = (value_type)((p[Order::G] * s1a + sg * d1a + base_mask) >> base_shift);
            p[Order::B] = (value_type)((p[Order::B] * s1a + sb * d1a + base_mask) >> base_shift);
            p[Order::A] = (value_type)(sa + p[Order::A] - ((sa * p[Order::A] + base_mask/2) >> (base_shift - 1)));
        }
    }
};

//=========================================================comp_op_rgba_plus
template<class ColorT, class Order> struct comp_op_rgba_plus
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca + Dca
    // Da'  = Sa + Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type dr = p[Order::R] + sr;
            calc_type dg = p[Order::G] + sg;
            calc_type db = p[Order::B] + sb;
            calc_type da = p[Order::A] + sa;
            p[Order::R] = (dr > base_mask) ? (value_type)base_mask : dr;
            p[Order::G] = (dg > base_mask) ? (value_type)base_mask : dg;
            p[Order::B] = (db > base_mask) ? (value_type)base_mask : db;
            p[Order::A] = (da > base_mask) ? (value_type)base_mask : da;
        }
    }
};

//========================================================comp_op_rgba_minus
template<class ColorT, class Order> struct comp_op_rgba_minus
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Dca - Sca
    // Da' = 1 - (1 - Sa).(1 - Da)
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type dr = (sr > p[Order::R]) ? 0 : p[Order::R] - sr;
            calc_type dg = (sg > p[Order::G]) ? 0 : p[Order::G] - sg;
            calc_type db = (sb > p[Order::B]) ? 0 : p[Order::B] - sb;
            p[Order::R] = (dr > base_mask) ? 0 : dr;
            p[Order::G] = (dg > base_mask) ? 0 : dg;
            p[Order::B] = (db > base_mask) ? 0 : db;
            p[Order::A] = (value_type)(sa + p[Order::A] - ((sa * p[Order::A] + base_mask) >> base_shift));
            //p[Order::A] = (value_type)(base_mask - (((base_mask - sa) * (base_mask - p[Order::A]) + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_multiply
template<class ColorT, class Order> struct comp_op_rgba_multiply
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca.Dca + Sca.(1 - Da) + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type s1a = base_mask - sa;
            calc_type d1a = base_mask - p[Order::A];
            calc_type dr = p[Order::R];
            calc_type dg = p[Order::G];
            calc_type db = p[Order::B];
            p[Order::R] = (value_type)((sr * dr + sr * d1a + dr * s1a + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sg * dg + sg * d1a + dg * s1a + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sb * db + sb * d1a + db * s1a + base_mask) >> base_shift);
            p[Order::A] = (value_type)(sa + p[Order::A] - ((sa * p[Order::A] + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_screen
template<class ColorT, class Order> struct comp_op_rgba_screen
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca + Dca - Sca.Dca
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type dr = p[Order::R];
            calc_type dg = p[Order::G];
            calc_type db = p[Order::B];
            calc_type da = p[Order::A];
            p[Order::R] = (value_type)(sr + dr - ((sr * dr + base_mask) >> base_shift));
            p[Order::G] = (value_type)(sg + dg - ((sg * dg + base_mask) >> base_shift));
            p[Order::B] = (value_type)(sb + db - ((sb * db + base_mask) >> base_shift));
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_overlay
template<class ColorT, class Order> struct comp_op_rgba_overlay
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // if 2.Dca < Da
    //   Dca' = 2.Sca.Dca + Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise
    //   Dca' = Sa.Da - 2.(Da - Dca).(Sa - Sca) + Sca.(1 - Da) + Dca.(1 - Sa)
    //
    // Da' = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a  = base_mask - p[Order::A];
            calc_type s1a  = base_mask - sa;
            calc_type dr   = p[Order::R];
            calc_type dg   = p[Order::G];
            calc_type db   = p[Order::B];
            calc_type da   = p[Order::A];
            calc_type sada = sa * p[Order::A];

            p[Order::R] = (value_type)(((2*dr < da) ?
                                        2*sr*dr + sr*d1a + dr*s1a :
                                        sada - 2*(da - dr)*(sa - sr) + sr*d1a + dr*s1a + base_mask) >> base_shift);

            p[Order::G] = (value_type)(((2*dg < da) ?
                                        2*sg*dg + sg*d1a + dg*s1a :
                                        sada - 2*(da - dg)*(sa - sg) + sg*d1a + dg*s1a + base_mask) >> base_shift);

            p[Order::B] = (value_type)(((2*db < da) ?
                                        2*sb*db + sb*d1a + db*s1a :
                                        sada - 2*(da - db)*(sa - sb) + sb*d1a + db*s1a + base_mask) >> base_shift);

            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};


template<class T> inline T sd_min(T a, T b) { return (a < b) ? a : b; }
template<class T> inline T sd_max(T a, T b) { return (a > b) ? a : b; }

//=====================================================comp_op_rgba_darken
template<class ColorT, class Order> struct comp_op_rgba_darken
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = min(Sca.Da, Dca.Sa) + Sca.(1 - Da) + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a = base_mask - p[Order::A];
            calc_type s1a = base_mask - sa;
            calc_type dr  = p[Order::R];
            calc_type dg  = p[Order::G];
            calc_type db  = p[Order::B];
            calc_type da  = p[Order::A];

            p[Order::R] = (value_type)((sd_min(sr * da, dr * sa) + sr * d1a + dr * s1a + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sd_min(sg * da, dg * sa) + sg * d1a + dg * s1a + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sd_min(sb * da, db * sa) + sb * d1a + db * s1a + base_mask) >> base_shift);
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_lighten
template<class ColorT, class Order> struct comp_op_rgba_lighten
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = max(Sca.Da, Dca.Sa) + Sca.(1 - Da) + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a = base_mask - p[Order::A];
            calc_type s1a = base_mask - sa;
            calc_type dr  = p[Order::R];
            calc_type dg  = p[Order::G];
            calc_type db  = p[Order::B];
            calc_type da  = p[Order::A];

            p[Order::R] = (value_type)((sd_max(sr * da, dr * sa) + sr * d1a + dr * s1a + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sd_max(sg * da, dg * sa) + sg * d1a + dg * s1a + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sd_max(sb * da, db * sa) + sb * d1a + db * s1a + base_mask) >> base_shift);
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_color_dodge
template<class ColorT, class Order> struct comp_op_rgba_color_dodge
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // if Sca.Da + Dca.Sa >= Sa.Da
    //   Dca' = Sa.Da + Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise
    //   Dca' = Dca.Sa/(1-Sca/Sa) + Sca.(1 - Da) + Dca.(1 - Sa)
    //
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a  = base_mask - p[Order::A];
            calc_type s1a  = base_mask - sa;
            calc_type dr   = p[Order::R];
            calc_type dg   = p[Order::G];
            calc_type db   = p[Order::B];
            calc_type da   = p[Order::A];
            long_type drsa = dr * sa;
            long_type dgsa = dg * sa;
            long_type dbsa = db * sa;
            long_type srda = sr * da;
            long_type sgda = sg * da;
            long_type sbda = sb * da;
            long_type sada = sa * da;

            p[Order::R] = (value_type)((srda + drsa >= sada) ?
                                       (sada + sr * d1a + dr * s1a + base_mask) >> base_shift :
                                       drsa / (base_mask - (sr << base_shift) / sa) + ((sr * d1a + dr * s1a + base_mask) >> base_shift));

            p[Order::G] = (value_type)((sgda + dgsa >= sada) ?
                                       (sada + sg * d1a + dg * s1a + base_mask) >> base_shift :
                                       dgsa / (base_mask - (sg << base_shift) / sa) + ((sg * d1a + dg * s1a + base_mask) >> base_shift));

            p[Order::B] = (value_type)((sbda + dbsa >= sada) ?
                                       (sada + sb * d1a + db * s1a + base_mask) >> base_shift :
                                       dbsa / (base_mask - (sb << base_shift) / sa) + ((sb * d1a + db * s1a + base_mask) >> base_shift));

            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_color_burn
template<class ColorT, class Order> struct comp_op_rgba_color_burn
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // if Sca.Da + Dca.Sa <= Sa.Da
    //   Dca' = Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise
    //   Dca' = Sa.(Sca.Da + Dca.Sa - Sa.Da)/Sca + Sca.(1 - Da) + Dca.(1 - Sa)
    //
    // Da'  = Sa + Da - Sa.Da


    // http://www.w3.org/TR/SVGCompositing/
    // if Sca == 0 and Dca == Da
    //   Dca' = Sa × Da + Sca × (1 - Da) + Dca × (1 - Sa)
    //        = Sa × Da + Dca × (1 - Sa)
    //        = Da = Dca
    // otherwise if Sca == 0
    //   Dca' = Sca × (1 - Da) + Dca × (1 - Sa)
    //        = Dca × (1 - Sa)
    // otherwise if Sca > 0
    //   Dca' = Sa × Da - Sa × Da × min(1, (1 - Dca/Da) × Sa/Sca) + Sca × (1 - Da) + Dca × (1 - Sa)
    //        = Sa × Da × (1 - min(1, (1 - Dca/Da) × Sa/Sca)) + Sca × (1 - Da) + Dca × (1 - Sa)

    //   sa * da * (255 - std::min(255, (255 - p[0]/da)*(sa/(sc*sa)) +
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if (cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }

        if (sa)
        {
            calc_type d1a  = base_mask - p[Order::A];
            calc_type s1a  = base_mask - sa;
            calc_type dr   = p[Order::R];
            calc_type dg   = p[Order::G];
            calc_type db   = p[Order::B];
            calc_type da   = p[Order::A];
            long_type drsa = dr * sa;
            long_type dgsa = dg * sa;
            long_type dbsa = db * sa;
            long_type srda = sr * da;
            long_type sgda = sg * da;
            long_type sbda = sb * da;
            long_type sada = sa * da;

            p[Order::R] = (value_type)(((srda + drsa <= sada) ?
                                        sr * d1a + dr * s1a :
                                        (sr > 0 ? sa * (srda + drsa - sada) / sr + sr * d1a + dr * s1a + base_mask : 0)) >> base_shift);

            p[Order::G] = (value_type)(((sgda + dgsa <= sada) ?
                                        sg * d1a + dg * s1a :
                                        (sg > 0 ? sa * (sgda + dgsa - sada) / sg + sg * d1a + dg * s1a + base_mask : 0)) >> base_shift);

            p[Order::B] = (value_type)(((sbda + dbsa <= sada) ?
                                        sb * d1a + db * s1a :
                                        (sb > 0 ? sa * (sbda + dbsa - sada) / sb + sb * d1a + db * s1a + base_mask : 0)) >> base_shift);

            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_hard_light
template<class ColorT, class Order> struct comp_op_rgba_hard_light
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // if 2.Sca < Sa
    //    Dca' = 2.Sca.Dca + Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise
    //    Dca' = Sa.Da - 2.(Da - Dca).(Sa - Sca) + Sca.(1 - Da) + Dca.(1 - Sa)
    //
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a  = base_mask - p[Order::A];
            calc_type s1a  = base_mask - sa;
            calc_type dr   = p[Order::R];
            calc_type dg   = p[Order::G];
            calc_type db   = p[Order::B];
            calc_type da   = p[Order::A];
            calc_type sada = sa * da;

            p[Order::R] = (value_type)(((2*sr < sa) ?
                                        2*sr*dr + sr*d1a + dr*s1a :
                                        sada - 2*(da - dr)*(sa - sr) + sr*d1a + dr*s1a + base_mask) >> base_shift);

            p[Order::G] = (value_type)(((2*sg < sa) ?
                                        2*sg*dg + sg*d1a + dg*s1a :
                                        sada - 2*(da - dg)*(sa - sg) + sg*d1a + dg*s1a + base_mask) >> base_shift);

            p[Order::B] = (value_type)(((2*sb < sa) ?
                                        2*sb*db + sb*d1a + db*s1a :
                                        sada - 2*(da - db)*(sa - sb) + sb*d1a + db*s1a + base_mask) >> base_shift);

            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_soft_light
template<class ColorT, class Order> struct comp_op_rgba_soft_light
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // if 2.Sca < Sa
    //   Dca' = Dca.(Sa + (1 - Dca/Da).(2.Sca - Sa)) + Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise if 8.Dca <= Da
    //   Dca' = Dca.(Sa + (1 - Dca/Da).(2.Sca - Sa).(3 - 8.Dca/Da)) + Sca.(1 - Da) + Dca.(1 - Sa)
    // otherwise
    //   Dca' = (Dca.Sa + ((Dca/Da)^(0.5).Da - Dca).(2.Sca - Sa)) + Sca.(1 - Da) + Dca.(1 - Sa)
    //
    // Da'  = Sa + Da - Sa.Da

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned r, unsigned g, unsigned b,
                                     unsigned a, unsigned cover)
    {
        double sr = double(r * cover) / (base_mask * 255);
        double sg = double(g * cover) / (base_mask * 255);
        double sb = double(b * cover) / (base_mask * 255);
        double sa = double(a * cover) / (base_mask * 255);
        if(sa > 0)
        {
            double dr = double(p[Order::R]) / base_mask;
            double dg = double(p[Order::G]) / base_mask;
            double db = double(p[Order::B]) / base_mask;
            double da = double(p[Order::A] ? p[Order::A] : 1) / base_mask;
            if(cover < 255)
            {
                a = (a * cover + 255) >> 8;
            }

            if(2*sr < sa)       dr = dr*(sa + (1 - dr/da)*(2*sr - sa)) + sr*(1 - da) + dr*(1 - sa);
            else if(8*dr <= da) dr = dr*(sa + (1 - dr/da)*(2*sr - sa)*(3 - 8*dr/da)) + sr*(1 - da) + dr*(1 - sa);
            else                dr = (dr*sa + (sqrt(dr/da)*da - dr)*(2*sr - sa)) + sr*(1 - da) + dr*(1 - sa);

            if(2*sg < sa)       dg = dg*(sa + (1 - dg/da)*(2*sg - sa)) + sg*(1 - da) + dg*(1 - sa);
            else if(8*dg <= da) dg = dg*(sa + (1 - dg/da)*(2*sg - sa)*(3 - 8*dg/da)) + sg*(1 - da) + dg*(1 - sa);
            else                dg = (dg*sa + (sqrt(dg/da)*da - dg)*(2*sg - sa)) + sg*(1 - da) + dg*(1 - sa);

            if(2*sb < sa)       db = db*(sa + (1 - db/da)*(2*sb - sa)) + sb*(1 - da) + db*(1 - sa);
            else if(8*db <= da) db = db*(sa + (1 - db/da)*(2*sb - sa)*(3 - 8*db/da)) + sb*(1 - da) + db*(1 - sa);
            else                db = (db*sa + (sqrt(db/da)*da - db)*(2*sb - sa)) + sb*(1 - da) + db*(1 - sa);

            p[Order::R] = (value_type)uround(dr * base_mask);
            p[Order::G] = (value_type)uround(dg * base_mask);
            p[Order::B] = (value_type)uround(db * base_mask);
            p[Order::A] = (value_type)(a + p[Order::A] - ((a * p[Order::A] + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_difference
template<class ColorT, class Order> struct comp_op_rgba_difference
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_scale = color_type::base_scale,
        base_mask  = color_type::base_mask
    };

    // Dca' = Sca + Dca - 2.min(Sca.Da, Dca.Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type dr = p[Order::R];
            calc_type dg = p[Order::G];
            calc_type db = p[Order::B];
            calc_type da = p[Order::A];
            p[Order::R] = (value_type)(sr + dr - ((2 * sd_min(sr*da, dr*sa) + base_mask) >> base_shift));
            p[Order::G] = (value_type)(sg + dg - ((2 * sd_min(sg*da, dg*sa) + base_mask) >> base_shift));
            p[Order::B] = (value_type)(sb + db - ((2 * sd_min(sb*da, db*sa) + base_mask) >> base_shift));
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_exclusion
template<class ColorT, class Order> struct comp_op_rgba_exclusion
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = (Sca.Da + Dca.Sa - 2.Sca.Dca) + Sca.(1 - Da) + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type d1a = base_mask - p[Order::A];
            calc_type s1a = base_mask - sa;
            calc_type dr = p[Order::R];
            calc_type dg = p[Order::G];
            calc_type db = p[Order::B];
            calc_type da = p[Order::A];
            p[Order::R] = (value_type)((sr*da + dr*sa - 2*sr*dr + sr*d1a + dr*s1a + base_mask) >> base_shift);
            p[Order::G] = (value_type)((sg*da + dg*sa - 2*sg*dg + sg*d1a + dg*s1a + base_mask) >> base_shift);
            p[Order::B] = (value_type)((sb*da + db*sa - 2*sb*db + sb*d1a + db*s1a + base_mask) >> base_shift);
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=====================================================comp_op_rgba_contrast
template<class ColorT, class Order> struct comp_op_rgba_contrast
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };


    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        long_type dr = p[Order::R];
        long_type dg = p[Order::G];
        long_type db = p[Order::B];
        int       da = p[Order::A];
        long_type d2a = da >> 1;
        unsigned s2a = sa >> 1;

        int r = (int)((((dr - d2a) * int((sr - s2a)*2 + base_mask)) >> base_shift) + d2a);
        int g = (int)((((dg - d2a) * int((sg - s2a)*2 + base_mask)) >> base_shift) + d2a);
        int b = (int)((((db - d2a) * int((sb - s2a)*2 + base_mask)) >> base_shift) + d2a);

        r = (r < 0) ? 0 : r;
        g = (g < 0) ? 0 : g;
        b = (b < 0) ? 0 : b;

        p[Order::R] = (value_type)((r > da) ? da : r);
        p[Order::G] = (value_type)((g > da) ? da : g);
        p[Order::B] = (value_type)((b > da) ? da : b);
    }
};

//=====================================================comp_op_rgba_invert
template<class ColorT, class Order> struct comp_op_rgba_invert
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = (Da - Dca) * Sa + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned /*sr*/, unsigned /*sg*/, unsigned /*sb*/,
                                     unsigned sa, unsigned cover)
    {
        sa = (sa * cover + 255) >> 8;
        if(sa)
        {
            calc_type da = p[Order::A];
            calc_type dr = ((da - p[Order::R]) * sa + base_mask) >> base_shift;
            calc_type dg = ((da - p[Order::G]) * sa + base_mask) >> base_shift;
            calc_type db = ((da - p[Order::B]) * sa + base_mask) >> base_shift;
            calc_type s1a = base_mask - sa;
            p[Order::R] = (value_type)(dr + ((p[Order::R] * s1a + base_mask) >> base_shift));
            p[Order::G] = (value_type)(dg + ((p[Order::G] * s1a + base_mask) >> base_shift));
            p[Order::B] = (value_type)(db + ((p[Order::B] * s1a + base_mask) >> base_shift));
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

//=================================================comp_op_rgba_invert_rgb
template<class ColorT, class Order> struct comp_op_rgba_invert_rgb
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    // Dca' = (Da - Dca) * Sca + Dca.(1 - Sa)
    // Da'  = Sa + Da - Sa.Da
    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if(cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if(sa)
        {
            calc_type da = p[Order::A];
            calc_type dr = ((da - p[Order::R]) * sr + base_mask) >> base_shift;
            calc_type dg = ((da - p[Order::G]) * sg + base_mask) >> base_shift;
            calc_type db = ((da - p[Order::B]) * sb + base_mask) >> base_shift;
            calc_type s1a = base_mask - sa;
            p[Order::R] = (value_type)(dr + ((p[Order::R] * s1a + base_mask) >> base_shift));
            p[Order::G] = (value_type)(dg + ((p[Order::G] * s1a + base_mask) >> base_shift));
            p[Order::B] = (value_type)(db + ((p[Order::B] * s1a + base_mask) >> base_shift));
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};


// merge grain (GIMP)
// E = I + M - 128

template <typename ColorT, typename Order>
struct comp_op_rgba_grain_merge
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {

        if (cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }
        if (sa > 0)
        {
            calc_type da = p[Order::A];
            int dr = sr + p[Order::R] - 128;
            int dg = sg + p[Order::G] - 128;
            int db = sb + p[Order::B] - 128;
            p[Order::R] = dr < 0 ? 0 : (dr > 255 ? 255 : dr);
            p[Order::G] = dg < 0 ? 0 : (dg > 255 ? 255 : dg);
            p[Order::B] = db < 0 ? 0 : (db > 255 ? 255 : db);
            p[Order::A] = (value_type)(sa + da - ((sa * da + base_mask) >> base_shift));
        }
    }
};

// grain extract (GIMP)
// E = I - M + 128
// FIXME: https://github.com/mapnik/mapnik/issues/2067
template <typename ColorT, typename Order>
struct comp_op_rgba_grain_extract
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned /*cover*/)
    {
        calc_type da = (p[Order::A] * sa + 255) >> 8;

        int dr = p[Order::R] - sr + 128;
        int dg = p[Order::G] - sg + 128;
        int db = p[Order::B] - sb + 128;

        dr = dr < 0 ? 0 : (dr > 255 ? 255 : dr);
        dg = dg < 0 ? 0 : (dg > 255 ? 255 : dg);
        db = db < 0 ? 0 : (db > 255 ? 255 : db);

        p[Order::A] = da;

        if (da < 255)
        {
            p[Order::R] = (dr * da + 255) >> 8;
            p[Order::G] = (dg * da + 255) >> 8;
            p[Order::B] = (db * da + 255) >> 8;
        }
        else
        {
            p[Order::R] = dr;
            p[Order::G] = dg;
            p[Order::B] = db;
        }
    }
};

template <typename ColorT, typename Order>
struct comp_op_rgba_hue
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static void blend_pix(value_type* p,
                          unsigned sr, unsigned sg, unsigned sb,
                          unsigned sa, unsigned cover);
};

template <typename ColorT, typename Order>
struct comp_op_rgba_saturation
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static void blend_pix(value_type* p,
                          unsigned sr, unsigned sg, unsigned sb,
                          unsigned sa, unsigned cover);
};

template <typename ColorT, typename Order>
struct comp_op_rgba_color
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static void blend_pix(value_type* p,
                          unsigned sr, unsigned sg, unsigned sb,
                          unsigned sa, unsigned cover);
};


template <typename ColorT, typename Order>
struct comp_op_rgba_value
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static void blend_pix(value_type* p,
                          unsigned sr, unsigned sg, unsigned sb,
                          unsigned sa, unsigned cover);
};

// Linear dodge: Target + Blend
template <typename ColorT, typename Order>
struct comp_op_rgba_linear_dodge
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;

    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if (cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }

        calc_type dr = p[Order::R] + sr;
        calc_type dg = p[Order::G] + sg;
        calc_type db = p[Order::B] + sb;
        p[Order::R] = (dr > base_mask) ? (value_type)base_mask : dr;
        p[Order::G] = (dg > base_mask) ? (value_type)base_mask : dg;
        p[Order::B] = (db > base_mask) ? (value_type)base_mask : db;
        p[Order::A] = (value_type)(sa + ((p[Order::A] * (base_mask - sa) + base_mask) >> base_shift));
    }
};

// Linear burn: Target + Blend - 1
template <typename ColorT, typename Order>
struct comp_op_rgba_linear_burn
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if (cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }

        long_type dr = p[Order::R] + sr - base_mask;
        long_type dg = p[Order::G] + sg - base_mask;
        long_type db = p[Order::B] + sb - base_mask;
        p[Order::R] = (dr < 0) ? 0 : dr;
        p[Order::G] = (dg < 0) ? 0 : dg;
        p[Order::B] = (db < 0) ? 0 : db;
        p[Order::A] = (value_type)(sa + ((p[Order::A] * (base_mask - sa) + base_mask) >> base_shift));
    }
};

// Divide
template <typename ColorT, typename Order>
struct comp_op_rgba_divide
{
    typedef ColorT color_type;
    typedef Order order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::long_type long_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(value_type* p,
                                     unsigned sr, unsigned sg, unsigned sb,
                                     unsigned sa, unsigned cover)
    {
        if (cover < 255)
        {
            sr = (sr * cover + 255) >> 8;
            sg = (sg * cover + 255) >> 8;
            sb = (sb * cover + 255) >> 8;
            sa = (sa * cover + 255) >> 8;
        }

        float fr = (sr > 0) ? sr : 0.001;
        float fg = (sg > 0) ? sg : 0.001;
        float fb = (sb > 0) ? sb : 0.001;

        long_type dr = long_type(p[Order::R]/((fr + 1) / 256));
        long_type dg = long_type(p[Order::G]/((fg + 1) / 256));
        long_type db = long_type(p[Order::B]/((fb + 1) / 256));

        p[Order::R] = (dr > 255) ? 255 : dr;
        p[Order::G] = (dg > 255) ? 255 : dg;
        p[Order::B] = (db > 255) ? 255 : db;

        p[Order::A] = (value_type)(sa + ((p[Order::A] * (base_mask - sa) + base_mask) >> base_shift));
    }
};


//======================================================comp_op_table_rgba
template<class ColorT, class Order> struct comp_op_table_rgba
{
    typedef typename ColorT::value_type value_type;
    typedef void (*comp_op_func_type)(value_type* p,
                                      unsigned cr,
                                      unsigned cg,
                                      unsigned cb,
                                      unsigned ca,
                                      unsigned cover);
    static comp_op_func_type g_comp_op_func[];
};

//==========================================================g_comp_op_func
template<class ColorT, class Order>
typename comp_op_table_rgba<ColorT, Order>::comp_op_func_type
comp_op_table_rgba<ColorT, Order>::g_comp_op_func[] =
{
    comp_op_rgba_clear      <ColorT,Order>::blend_pix,
    comp_op_rgba_src        <ColorT,Order>::blend_pix,
    comp_op_rgba_dst        <ColorT,Order>::blend_pix,
    comp_op_rgba_src_over   <ColorT,Order>::blend_pix,
    comp_op_rgba_dst_over   <ColorT,Order>::blend_pix,
    comp_op_rgba_src_in     <ColorT,Order>::blend_pix,
    comp_op_rgba_dst_in     <ColorT,Order>::blend_pix,
    comp_op_rgba_src_out    <ColorT,Order>::blend_pix,
    comp_op_rgba_dst_out    <ColorT,Order>::blend_pix,
    comp_op_rgba_src_atop   <ColorT,Order>::blend_pix,
    comp_op_rgba_dst_atop   <ColorT,Order>::blend_pix,
    comp_op_rgba_xor        <ColorT,Order>::blend_pix,
    comp_op_rgba_plus       <ColorT,Order>::blend_pix,
    comp_op_rgba_minus      <ColorT,Order>::blend_pix,
    comp_op_rgba_multiply   <ColorT,Order>::blend_pix,
    comp_op_rgba_screen     <ColorT,Order>::blend_pix,
    comp_op_rgba_overlay    <ColorT,Order>::blend_pix,
    comp_op_rgba_darken     <ColorT,Order>::blend_pix,
    comp_op_rgba_lighten    <ColorT,Order>::blend_pix,
    comp_op_rgba_color_dodge<ColorT,Order>::blend_pix,
    comp_op_rgba_color_burn <ColorT,Order>::blend_pix,
    comp_op_rgba_hard_light <ColorT,Order>::blend_pix,
    comp_op_rgba_soft_light <ColorT,Order>::blend_pix,
    comp_op_rgba_difference <ColorT,Order>::blend_pix,
    comp_op_rgba_exclusion  <ColorT,Order>::blend_pix,
    comp_op_rgba_contrast   <ColorT,Order>::blend_pix,
    comp_op_rgba_invert     <ColorT,Order>::blend_pix,
    comp_op_rgba_invert_rgb <ColorT,Order>::blend_pix,
    comp_op_rgba_grain_merge<ColorT,Order>::blend_pix,
    comp_op_rgba_grain_extract<ColorT,Order>::blend_pix,
    comp_op_rgba_hue<ColorT,Order>::blend_pix,
    comp_op_rgba_saturation<ColorT,Order>::blend_pix,
    comp_op_rgba_color<ColorT,Order>::blend_pix,
    comp_op_rgba_value<ColorT,Order>::blend_pix,
    comp_op_rgba_linear_dodge<ColorT,Order>::blend_pix,
    comp_op_rgba_linear_burn<ColorT,Order>::blend_pix,
    comp_op_rgba_divide<ColorT,Order>::blend_pix,
    //comp_op_rgba_colorize_alpha<ColorT,Order>::blend_pix,
    0
};


//==============================================================comp_op_e
enum comp_op_e
{
    comp_op_clear,         //----comp_op_clear
    comp_op_src,           //----comp_op_src
    comp_op_dst,           //----comp_op_dst
    comp_op_src_over,      //----comp_op_src_over
    comp_op_dst_over,      //----comp_op_dst_over
    comp_op_src_in,        //----comp_op_src_in
    comp_op_dst_in,        //----comp_op_dst_in
    comp_op_src_out,       //----comp_op_src_out
    comp_op_dst_out,       //----comp_op_dst_out
    comp_op_src_atop,      //----comp_op_src_atop
    comp_op_dst_atop,      //----comp_op_dst_atop
    comp_op_xor,           //----comp_op_xor
    comp_op_plus,          //----comp_op_plus
    comp_op_minus,         //----comp_op_minus
    comp_op_multiply,      //----comp_op_multiply
    comp_op_screen,        //----comp_op_screen
    comp_op_overlay,       //----comp_op_overlay
    comp_op_darken,        //----comp_op_darken
    comp_op_lighten,       //----comp_op_lighten
    comp_op_color_dodge,   //----comp_op_color_dodge
    comp_op_color_burn,    //----comp_op_color_burn
    comp_op_hard_light,    //----comp_op_hard_light
    comp_op_soft_light,    //----comp_op_soft_light
    comp_op_difference,    //----comp_op_difference
    comp_op_exclusion,     //----comp_op_exclusion
    comp_op_contrast,      //----comp_op_contrast
    comp_op_invert,        //----comp_op_invert
    comp_op_invert_rgb,    //----comp_op_invert_rgb
    comp_op_grain_merge,   //----comp_op_grain_merge_rgb
    comp_op_grain_extract, //----comp_op_grain_extract_rgb
    comp_op_hue,           //----comp_op_hue
    comp_op_saturation,    //----comp_op_saturation
    comp_op_color,         //----comp_op_color
    comp_op_value,         //----comp_op_value
    //comp_op_colorize_alpha,//----comp_op_colorize_alpha
    comp_op_linear_dodge, // comp_op_linear_dodge
    comp_op_linear_burn, // comp_op_linear_burn
    comp_op_divide, // comp_op_divide
    end_of_comp_op_e
};

//====================================================comp_op_adaptor_rgba
template<class ColorT, class Order> struct comp_op_adaptor_rgba
{
    typedef Order  order_type;
    typedef ColorT color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned op, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        comp_op_table_rgba<ColorT, Order>::g_comp_op_func[op]
            (p, (cr * ca + base_mask) >> base_shift,
             (cg * ca + base_mask) >> base_shift,
             (cb * ca + base_mask) >> base_shift,
             ca, cover);
    }
};

//=========================================comp_op_adaptor_clip_to_dst_rgba
template<class ColorT, class Order> struct comp_op_adaptor_clip_to_dst_rgba
{
    typedef Order  order_type;
    typedef ColorT color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned op, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        cr = (cr * ca + base_mask) >> base_shift;
        cg = (cg * ca + base_mask) >> base_shift;
        cb = (cb * ca + base_mask) >> base_shift;
        unsigned da = p[Order::A];
        comp_op_table_rgba<ColorT, Order>::g_comp_op_func[op]
            (p, (cr * da + base_mask) >> base_shift,
             (cg * da + base_mask) >> base_shift,
             (cb * da + base_mask) >> base_shift,
             (ca * da + base_mask) >> base_shift,
             cover);
    }
};

//================================================comp_op_adaptor_rgba_pre
template<class ColorT, class Order> struct comp_op_adaptor_rgba_pre
{
    typedef Order  order_type;
    typedef ColorT color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned op, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        comp_op_table_rgba<ColorT, Order>::g_comp_op_func[op](p, cr, cg, cb, ca, cover);
    }
};

//=====================================comp_op_adaptor_clip_to_dst_rgba_pre
template<class ColorT, class Order> struct comp_op_adaptor_clip_to_dst_rgba_pre
{
    typedef Order  order_type;
    typedef ColorT color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned op, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        unsigned da = p[Order::A];
        comp_op_table_rgba<ColorT, Order>::g_comp_op_func[op]
            (p, (cr * da + base_mask) >> base_shift,
             (cg * da + base_mask) >> base_shift,
             (cb * da + base_mask) >> base_shift,
             (ca * da + base_mask) >> base_shift,
             cover);
    }
};

//=======================================================comp_adaptor_rgba
template<class BlenderPre> struct comp_adaptor_rgba
{
    typedef typename BlenderPre::order_type order_type;
    typedef typename BlenderPre::color_type color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned /*op*/, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        BlenderPre::blend_pix(p,
                              (cr * ca + base_mask) >> base_shift,
                              (cg * ca + base_mask) >> base_shift,
                              (cb * ca + base_mask) >> base_shift,
                              ca, cover);
    }
};

//==========================================comp_adaptor_clip_to_dst_rgba
template<class BlenderPre> struct comp_adaptor_clip_to_dst_rgba
{
    typedef typename BlenderPre::order_type order_type;
    typedef typename BlenderPre::color_type color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned /*op*/, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        cr = (cr * ca + base_mask) >> base_shift;
        cg = (cg * ca + base_mask) >> base_shift;
        cb = (cb * ca + base_mask) >> base_shift;
        unsigned da = p[order_type::A];
        BlenderPre::blend_pix(p,
                              (cr * da + base_mask) >> base_shift,
                              (cg * da + base_mask) >> base_shift,
                              (cb * da + base_mask) >> base_shift,
                              (ca * da + base_mask) >> base_shift,
                              cover);
    }
};

//======================================comp_adaptor_clip_to_dst_rgba_pre
template<class BlenderPre> struct comp_adaptor_clip_to_dst_rgba_pre
{
    typedef typename BlenderPre::order_type order_type;
    typedef typename BlenderPre::color_type color_type;
    typedef typename color_type::value_type value_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_mask  = color_type::base_mask
    };

    static AGG_INLINE void blend_pix(unsigned /*op*/, value_type* p,
                                     unsigned cr, unsigned cg, unsigned cb,
                                     unsigned ca,
                                     unsigned cover)
    {
        unsigned da = p[order_type::A];
        BlenderPre::blend_pix(p,
                              (cr * da + base_mask) >> base_shift,
                              (cg * da + base_mask) >> base_shift,
                              (cb * da + base_mask) >> base_shift,
                              (ca * da + base_mask) >> base_shift,
                              cover);
    }
};






//===============================================copy_or_blend_rgba_wrapper
template<class Blender> struct copy_or_blend_rgba_wrapper
{
    typedef typename Blender::color_type color_type;
    typedef typename Blender::order_type order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_scale = color_type::base_scale,
        base_mask  = color_type::base_mask
    };

    //--------------------------------------------------------------------
    static AGG_INLINE void copy_or_blend_pix(value_type* p,
                                             unsigned cr, unsigned cg, unsigned cb,
                                             unsigned alpha)
    {
        if(alpha)
        {
            if(alpha == base_mask)
            {
                p[order_type::R] = cr;
                p[order_type::G] = cg;
                p[order_type::B] = cb;
                p[order_type::A] = base_mask;
            }
            else
            {
                Blender::blend_pix(p, cr, cg, cb, alpha);
            }
        }
    }

    //--------------------------------------------------------------------
    static AGG_INLINE void copy_or_blend_pix(value_type* p,
                                             unsigned cr, unsigned cg, unsigned cb,
                                             unsigned alpha,
                                             unsigned cover)
    {
        if(cover == 255)
        {
            copy_or_blend_pix(p, cr, cg, cb, alpha);
        }
        else
        {
            if(alpha)
            {
                alpha = (alpha * (cover + 1)) >> 8;
                if(alpha == base_mask)
                {
                    p[order_type::R] = cr;
                    p[order_type::G] = cg;
                    p[order_type::B] = cb;
                    p[order_type::A] = base_mask;
                }
                else
                {
                    Blender::blend_pix(p, cr, cg, cb, alpha, cover);
                }
            }
        }
    }
};






//=================================================pixfmt_alpha_blend_rgba
template<class Blender, class RenBuf, class PixelT = int32u>
class pixfmt_alpha_blend_rgba
{
public:
    typedef RenBuf   rbuf_type;
    typedef typename rbuf_type::row_data row_data;
    typedef PixelT   pixel_type;
    typedef Blender  blender_type;
    typedef typename blender_type::color_type color_type;
    typedef typename blender_type::order_type order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    typedef copy_or_blend_rgba_wrapper<blender_type> cob_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_scale = color_type::base_scale,
        base_mask  = color_type::base_mask,
        pix_width  = sizeof(pixel_type)
    };

    //--------------------------------------------------------------------
    pixfmt_alpha_blend_rgba() : m_rbuf(0) {}
    explicit pixfmt_alpha_blend_rgba(rbuf_type& rb) : m_rbuf(&rb) {}
    void attach(rbuf_type& rb) { m_rbuf = &rb; }

    //--------------------------------------------------------------------
    template<class PixFmt>
    bool attach(PixFmt& pixf, int x1, int y1, int x2, int y2)
    {
        rect_i r(x1, y1, x2, y2);
        if(r.clip(rect_i(0, 0, pixf.width()-1, pixf.height()-1)))
        {
            int stride = pixf.stride();
            m_rbuf->attach(pixf.pix_ptr(r.x1, stride < 0 ? r.y2 : r.y1),
                           (r.x2 - r.x1) + 1,
                           (r.y2 - r.y1) + 1,
                           stride);
            return true;
        }
        return false;
    }

    //--------------------------------------------------------------------
    AGG_INLINE unsigned width()  const { return m_rbuf->width();  }
    AGG_INLINE unsigned height() const { return m_rbuf->height(); }
    AGG_INLINE int      stride() const { return m_rbuf->stride(); }

    //--------------------------------------------------------------------
    AGG_INLINE       int8u* row_ptr(int y)       { return m_rbuf->row_ptr(y); }
    AGG_INLINE const int8u* row_ptr(int y) const { return m_rbuf->row_ptr(y); }
    AGG_INLINE row_data     row(int y)     const { return m_rbuf->row(y); }

    //--------------------------------------------------------------------
    AGG_INLINE int8u* pix_ptr(int x, int y)
    {
        return m_rbuf->row_ptr(y) + x * pix_width;
    }

    AGG_INLINE const int8u* pix_ptr(int x, int y) const
    {
        return m_rbuf->row_ptr(y) + x * pix_width;
    }


    //--------------------------------------------------------------------
    AGG_INLINE static void make_pix(int8u* p, const color_type& c)
    {
        ((value_type*)p)[order_type::R] = c.r;
        ((value_type*)p)[order_type::G] = c.g;
        ((value_type*)p)[order_type::B] = c.b;
        ((value_type*)p)[order_type::A] = c.a;
    }

    //--------------------------------------------------------------------
    AGG_INLINE color_type pixel(int x, int y) const
    {
        const value_type* p = (const value_type*)m_rbuf->row_ptr(y);
        if(p)
        {
            p += x << 2;
            return color_type(p[order_type::R],
                              p[order_type::G],
                              p[order_type::B],
                              p[order_type::A]);
        }
        return color_type::no_color();
    }

    //--------------------------------------------------------------------
    AGG_INLINE void copy_pixel(int x, int y, const color_type& c)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, 1) + (x << 2);
        p[order_type::R] = c.r;
        p[order_type::G] = c.g;
        p[order_type::B] = c.b;
        p[order_type::A] = c.a;
    }

    //--------------------------------------------------------------------
    AGG_INLINE void blend_pixel(int x, int y, const color_type& c, int8u cover)
    {
        cob_type::copy_or_blend_pix(
            (value_type*)m_rbuf->row_ptr(x, y, 1) + (x << 2),
            c.r, c.g, c.b, c.a,
            cover);
    }


    //--------------------------------------------------------------------
    AGG_INLINE void copy_hline(int x, int y,
                               unsigned len,
                               const color_type& c)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        pixel_type v;
        ((value_type*)&v)[order_type::R] = c.r;
        ((value_type*)&v)[order_type::G] = c.g;
        ((value_type*)&v)[order_type::B] = c.b;
        ((value_type*)&v)[order_type::A] = c.a;
        do
        {
            *(pixel_type*)p = v;
            p += 4;
        }
        while(--len);
    }


    //--------------------------------------------------------------------
    AGG_INLINE void copy_vline(int x, int y,
                               unsigned len,
                               const color_type& c)
    {
        pixel_type v;
        ((value_type*)&v)[order_type::R] = c.r;
        ((value_type*)&v)[order_type::G] = c.g;
        ((value_type*)&v)[order_type::B] = c.b;
        ((value_type*)&v)[order_type::A] = c.a;
        do
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
            *(pixel_type*)p = v;
        }
        while(--len);
    }


    //--------------------------------------------------------------------
    void blend_hline(int x, int y,
                     unsigned len,
                     const color_type& c,
                     int8u cover)
    {
        if (c.a)
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
            calc_type alpha = (calc_type(c.a) * (cover + 1)) >> 8;
            if(alpha == base_mask)
            {
                pixel_type v;
                ((value_type*)&v)[order_type::R] = c.r;
                ((value_type*)&v)[order_type::G] = c.g;
                ((value_type*)&v)[order_type::B] = c.b;
                ((value_type*)&v)[order_type::A] = c.a;
                do
                {
                    *(pixel_type*)p = v;
                    p += 4;
                }
                while(--len);
            }
            else
            {
                if(cover == 255)
                {
                    do
                    {
                        blender_type::blend_pix(p, c.r, c.g, c.b, alpha);
                        p += 4;
                    }
                    while(--len);
                }
                else
                {
                    do
                    {
                        blender_type::blend_pix(p, c.r, c.g, c.b, alpha, cover);
                        p += 4;
                    }
                    while(--len);
                }
            }
        }
    }


    //--------------------------------------------------------------------
    void blend_vline(int x, int y,
                     unsigned len,
                     const color_type& c,
                     int8u cover)
    {
        if (c.a)
        {
            value_type* p;
            calc_type alpha = (calc_type(c.a) * (cover + 1)) >> 8;
            if(alpha == base_mask)
            {
                pixel_type v;
                ((value_type*)&v)[order_type::R] = c.r;
                ((value_type*)&v)[order_type::G] = c.g;
                ((value_type*)&v)[order_type::B] = c.b;
                ((value_type*)&v)[order_type::A] = c.a;
                do
                {
                    p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                    *(pixel_type*)p = v;
                }
                while(--len);
            }
            else
            {
                if(cover == 255)
                {
                    do
                    {
                        p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                        blender_type::blend_pix(p, c.r, c.g, c.b, alpha);
                    }
                    while(--len);
                }
                else
                {
                    do
                    {
                        p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                        blender_type::blend_pix(p, c.r, c.g, c.b, alpha, cover);
                    }
                    while(--len);
                }
            }
        }
    }


    //--------------------------------------------------------------------
    void blend_solid_hspan(int x, int y,
                           unsigned len,
                           const color_type& c,
                           const int8u* covers)
    {
        if (c.a)
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
            do
            {
                calc_type alpha = (calc_type(c.a) * (calc_type(*covers) + 1)) >> 8;
                if(alpha == base_mask)
                {
                    p[order_type::R] = c.r;
                    p[order_type::G] = c.g;
                    p[order_type::B] = c.b;
                    p[order_type::A] = base_mask;
                }
                else
                {
                    blender_type::blend_pix(p, c.r, c.g, c.b, alpha, *covers);
                }
                p += 4;
                ++covers;
            }
            while(--len);
        }
    }


    //--------------------------------------------------------------------
    void blend_solid_vspan(int x, int y,
                           unsigned len,
                           const color_type& c,
                           const int8u* covers)
    {
        if (c.a)
        {
            do
            {
                value_type* p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                calc_type alpha = (calc_type(c.a) * (calc_type(*covers) + 1)) >> 8;
                if(alpha == base_mask)
                {
                    p[order_type::R] = c.r;
                    p[order_type::G] = c.g;
                    p[order_type::B] = c.b;
                    p[order_type::A] = base_mask;
                }
                else
                {
                    blender_type::blend_pix(p, c.r, c.g, c.b, alpha, *covers);
                }
                ++covers;
            }
            while(--len);
        }
    }


    //--------------------------------------------------------------------
    void copy_color_hspan(int x, int y,
                          unsigned len,
                          const color_type* colors)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            p[order_type::R] = colors->r;
            p[order_type::G] = colors->g;
            p[order_type::B] = colors->b;
            p[order_type::A] = colors->a;
            ++colors;
            p += 4;
        }
        while(--len);
    }


    //--------------------------------------------------------------------
    void copy_color_vspan(int x, int y,
                          unsigned len,
                          const color_type* colors)
    {
        do
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
            p[order_type::R] = colors->r;
            p[order_type::G] = colors->g;
            p[order_type::B] = colors->b;
            p[order_type::A] = colors->a;
            ++colors;
        }
        while(--len);
    }


    //--------------------------------------------------------------------
    void blend_color_hspan(int x, int y,
                           unsigned len,
                           const color_type* colors,
                           const int8u* covers,
                           int8u cover)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        if(covers)
        {
            do
            {
                cob_type::copy_or_blend_pix(p,
                                            colors->r,
                                            colors->g,
                                            colors->b,
                                            colors->a,
                                            *covers++);
                p += 4;
                ++colors;
            }
            while(--len);
        }
        else
        {
            if(cover == 255)
            {
                do
                {
                    cob_type::copy_or_blend_pix(p,
                                                colors->r,
                                                colors->g,
                                                colors->b,
                                                colors->a);
                    p += 4;
                    ++colors;
                }
                while(--len);
            }
            else
            {
                do
                {
                    cob_type::copy_or_blend_pix(p,
                                                colors->r,
                                                colors->g,
                                                colors->b,
                                                colors->a,
                                                cover);
                    p += 4;
                    ++colors;
                }
                while(--len);
            }
        }
    }



    //--------------------------------------------------------------------
    void blend_color_vspan(int x, int y,
                           unsigned len,
                           const color_type* colors,
                           const int8u* covers,
                           int8u cover)
    {
        value_type* p;
        if(covers)
        {
            do
            {
                p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                cob_type::copy_or_blend_pix(p,
                                            colors->r,
                                            colors->g,
                                            colors->b,
                                            colors->a,
                                            *covers++);
                ++colors;
            }
            while(--len);
        }
        else
        {
            if(cover == 255)
            {
                do
                {
                    p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                    cob_type::copy_or_blend_pix(p,
                                                colors->r,
                                                colors->g,
                                                colors->b,
                                                colors->a);
                    ++colors;
                }
                while(--len);
            }
            else
            {
                do
                {
                    p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
                    cob_type::copy_or_blend_pix(p,
                                                colors->r,
                                                colors->g,
                                                colors->b,
                                                colors->a,
                                                cover);
                    ++colors;
                }
                while(--len);
            }
        }
    }

    //--------------------------------------------------------------------
    template<class Function> void for_each_pixel(Function f)
    {
        unsigned y;
        for(y = 0; y < height(); ++y)
        {
            row_data r = m_rbuf->row(y);
            if(r.ptr)
            {
                unsigned len = r.x2 - r.x1 + 1;
                value_type* p =
                    (value_type*)m_rbuf->row_ptr(r.x1, y, len) + (r.x1 << 2);
                do
                {
                    f(p);
                    p += 4;
                }
                while(--len);
            }
        }
    }

    //--------------------------------------------------------------------
    void premultiply()
    {
        for_each_pixel(multiplier_rgba<color_type, order_type>::premultiply);
    }

    //--------------------------------------------------------------------
    void demultiply()
    {
        for_each_pixel(multiplier_rgba<color_type, order_type>::demultiply);
    }

    //--------------------------------------------------------------------
    template<class GammaLut> void apply_gamma_dir(const GammaLut& g)
    {
        for_each_pixel(apply_gamma_dir_rgba<color_type, order_type, GammaLut>(g));
    }

    //--------------------------------------------------------------------
    template<class GammaLut> void apply_gamma_inv(const GammaLut& g)
    {
        for_each_pixel(apply_gamma_inv_rgba<color_type, order_type, GammaLut>(g));
    }

    //--------------------------------------------------------------------
    template<class RenBuf2> void copy_from(const RenBuf2& from,
                                           int xdst, int ydst,
                                           int xsrc, int ysrc,
                                           unsigned len)
    {
        const int8u* p = from.row_ptr(ysrc);
        if(p)
        {
            memmove(m_rbuf->row_ptr(xdst, ydst, len) + xdst * pix_width,
                    p + xsrc * pix_width,
                    len * pix_width);
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from(const SrcPixelFormatRenderer& from,
                    int xdst, int ydst,
                    int xsrc, int ysrc,
                    unsigned len,
                    int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::order_type src_order;
        const value_type* psrc = (value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            psrc += xsrc << 2;
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);
            int incp = 4;
            if(xdst > xsrc)
            {
                psrc += (len-1) << 2;
                pdst += (len-1) << 2;
                incp = -4;
            }

            if(cover == 255)
            {
                do
                {
                    cob_type::copy_or_blend_pix(pdst,
                                                psrc[src_order::R],
                                                psrc[src_order::G],
                                                psrc[src_order::B],
                                                psrc[src_order::A]);
                    psrc += incp;
                    pdst += incp;
                }
                while(--len);
            }
            else
            {
                do
                {
                    cob_type::copy_or_blend_pix(pdst,
                                                psrc[src_order::R],
                                                psrc[src_order::G],
                                                psrc[src_order::B],
                                                psrc[src_order::A],
                                                cover);
                    psrc += incp;
                    pdst += incp;
                }
                while(--len);
            }
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from_color(const SrcPixelFormatRenderer& from,
                          const color_type& color,
                          int xdst, int ydst,
                          int /*xsrc*/, int ysrc,
                          unsigned len,
                          int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::value_type src_value_type;
        const src_value_type* psrc = (src_value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);
            do
            {
                cob_type::copy_or_blend_pix(pdst,
                                            color.r, color.g, color.b, color.a,
                                            (*psrc * cover + base_mask) >> base_shift);
                ++psrc;
                pdst += 4;
            }
            while(--len);
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from_lut(const SrcPixelFormatRenderer& from,
                        const color_type* color_lut,
                        int xdst, int ydst,
                        int /*xsrc*/, int ysrc,
                        unsigned len,
                        int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::value_type src_value_type;
        const src_value_type* psrc = (src_value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);

            if(cover == 255)
            {
                do
                {
                    const color_type& color = color_lut[*psrc];
                    cob_type::copy_or_blend_pix(pdst,
                                                color.r, color.g, color.b, color.a);
                    ++psrc;
                    pdst += 4;
                }
                while(--len);
            }
            else
            {
                do
                {
                    const color_type& color = color_lut[*psrc];
                    cob_type::copy_or_blend_pix(pdst,
                                                color.r, color.g, color.b, color.a,
                                                cover);
                    ++psrc;
                    pdst += 4;
                }
                while(--len);
            }
        }
    }

private:
    rbuf_type* m_rbuf;
};




//================================================pixfmt_custom_blend_rgba
template<class Blender, class RenBuf> class pixfmt_custom_blend_rgba
{
public:
    typedef RenBuf   rbuf_type;
    typedef typename rbuf_type::row_data row_data;
    typedef Blender  blender_type;
    typedef typename blender_type::color_type color_type;
    typedef typename blender_type::order_type order_type;
    typedef typename color_type::value_type value_type;
    typedef typename color_type::calc_type calc_type;
    enum base_scale_e
    {
        base_shift = color_type::base_shift,
        base_scale = color_type::base_scale,
        base_mask  = color_type::base_mask,
        pix_width  = sizeof(value_type) * 4
    };


    //--------------------------------------------------------------------
    pixfmt_custom_blend_rgba() : m_rbuf(0), m_comp_op(3) {}
    explicit pixfmt_custom_blend_rgba(rbuf_type& rb, unsigned comp_op=3) :
        m_rbuf(&rb),
        m_comp_op(comp_op)
    {}
    void attach(rbuf_type& rb) { m_rbuf = &rb; }

    //--------------------------------------------------------------------
    template<class PixFmt>
    bool attach(PixFmt& pixf, int x1, int y1, int x2, int y2)
    {
        rect_i r(x1, y1, x2, y2);
        if(r.clip(rect_i(0, 0, pixf.width()-1, pixf.height()-1)))
        {
            int stride = pixf.stride();
            m_rbuf->attach(pixf.pix_ptr(r.x1, stride < 0 ? r.y2 : r.y1),
                           (r.x2 - r.x1) + 1,
                           (r.y2 - r.y1) + 1,
                           stride);
            return true;
        }
        return false;
    }

    //--------------------------------------------------------------------
    AGG_INLINE unsigned width()  const { return m_rbuf->width();  }
    AGG_INLINE unsigned height() const { return m_rbuf->height(); }
    AGG_INLINE int      stride() const { return m_rbuf->stride(); }

    //--------------------------------------------------------------------
    AGG_INLINE       int8u* row_ptr(int y)       { return m_rbuf->row_ptr(y); }
    AGG_INLINE const int8u* row_ptr(int y) const { return m_rbuf->row_ptr(y); }
    AGG_INLINE row_data     row(int y)     const { return m_rbuf->row(y); }

    //--------------------------------------------------------------------
    AGG_INLINE int8u* pix_ptr(int x, int y)
    {
        return m_rbuf->row_ptr(y) + x * pix_width;
    }

    AGG_INLINE const int8u* pix_ptr(int x, int y) const
    {
        return m_rbuf->row_ptr(y) + x * pix_width;
    }

    //--------------------------------------------------------------------
    void comp_op(unsigned op) { m_comp_op = op; }
    unsigned comp_op() const  { return m_comp_op; }

    //--------------------------------------------------------------------
    AGG_INLINE static void make_pix(int8u* p, const color_type& c)
    {
        ((value_type*)p)[order_type::R] = c.r;
        ((value_type*)p)[order_type::G] = c.g;
        ((value_type*)p)[order_type::B] = c.b;
        ((value_type*)p)[order_type::A] = c.a;
    }

    //--------------------------------------------------------------------
    color_type pixel(int x, int y) const
    {
        const value_type* p = (value_type*)m_rbuf->row_ptr(y) + (x << 2);
        return color_type(p[order_type::R],
                          p[order_type::G],
                          p[order_type::B],
                          p[order_type::A]);
    }

    //--------------------------------------------------------------------
    void copy_pixel(int x, int y, const color_type& c)
    {
        blender_type::blend_pix(
            m_comp_op,
            (value_type*)m_rbuf->row_ptr(x, y, 1) + (x << 2),
            c.r, c.g, c.b, c.a, 255);
    }

    //--------------------------------------------------------------------
    void blend_pixel(int x, int y, const color_type& c, int8u cover)
    {
        blender_type::blend_pix(
            m_comp_op,
            (value_type*)m_rbuf->row_ptr(x, y, 1) + (x << 2),
            c.r, c.g, c.b, c.a,
            cover);
    }

    //--------------------------------------------------------------------
    void copy_hline(int x, int y, unsigned len, const color_type& c)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);;
        do
        {
            blender_type::blend_pix(m_comp_op, p, c.r, c.g, c.b, c.a, 255);
            p += 4;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void copy_vline(int x, int y, unsigned len, const color_type& c)
    {
        do
        {
            blender_type::blend_pix(
                m_comp_op,
                (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2),
                c.r, c.g, c.b, c.a, 255);
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_hline(int x, int y, unsigned len,
                     const color_type& c, int8u cover)
    {

        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            blender_type::blend_pix(m_comp_op, p, c.r, c.g, c.b, c.a, cover);
            p += 4;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_vline(int x, int y, unsigned len,
                     const color_type& c, int8u cover)
    {

        do
        {
            blender_type::blend_pix(
                m_comp_op,
                (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2),
                c.r, c.g, c.b, c.a,
                cover);
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_solid_hspan(int x, int y, unsigned len,
                           const color_type& c, const int8u* covers)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            blender_type::blend_pix(m_comp_op,
                                    p, c.r, c.g, c.b, c.a,
                                    *covers++);
            p += 4;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_solid_vspan(int x, int y, unsigned len,
                           const color_type& c, const int8u* covers)
    {
        do
        {
            blender_type::blend_pix(
                m_comp_op,
                (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2),
                c.r, c.g, c.b, c.a,
                *covers++);
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void copy_color_hspan(int x, int y,
                          unsigned len,
                          const color_type* colors)
    {

        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            p[order_type::R] = colors->r;
            p[order_type::G] = colors->g;
            p[order_type::B] = colors->b;
            p[order_type::A] = colors->a;
            ++colors;
            p += 4;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void copy_color_vspan(int x, int y,
                          unsigned len,
                          const color_type* colors)
    {
        do
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2);
            p[order_type::R] = colors->r;
            p[order_type::G] = colors->g;
            p[order_type::B] = colors->b;
            p[order_type::A] = colors->a;
            ++colors;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_color_hspan(int x, int y, unsigned len,
                           const color_type* colors,
                           const int8u* covers,
                           int8u cover)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            blender_type::blend_pix(m_comp_op,
                                    p,
                                    colors->r,
                                    colors->g,
                                    colors->b,
                                    colors->a,
                                    covers ? *covers++ : cover);
            p += 4;
            ++colors;
        }
        while(--len);
    }

    //--------------------------------------------------------------------
    void blend_color_hspan_alpha(int x, int y, unsigned len,
                                 const color_type* colors,
                                 value_type alpha,
                                 const int8u* covers,
                                 int8u cover)
    {
        value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + (x << 2);
        do
        {
            blender_type::blend_pix(m_comp_op,
                                    p,
                                    (colors->r * alpha + 255) >> 8,
                                    (colors->g * alpha + 255) >> 8,
                                    (colors->b * alpha + 255) >> 8,
                                    (colors->a * alpha + 255) >> 8,
                                    covers ? *covers++ : cover);
            p += 4;
            ++colors;
        }
        while(--len);
    }


    //--------------------------------------------------------------------
    void blend_color_vspan(int x, int y, unsigned len,
                           const color_type* colors,
                           const int8u* covers,
                           int8u cover)
    {
        do
        {
            blender_type::blend_pix(
                m_comp_op,
                (value_type*)m_rbuf->row_ptr(x, y++, 1) + (x << 2),
                colors->r,
                colors->g,
                colors->b,
                colors->a,
                covers ? *covers++ : cover);
            ++colors;
        }
        while(--len);

    }

    //--------------------------------------------------------------------
    template<class Function> void for_each_pixel(Function f)
    {
        unsigned y;
        for(y = 0; y < height(); ++y)
        {
            row_data r = m_rbuf->row(y);
            if(r.ptr)
            {
                unsigned len = r.x2 - r.x1 + 1;
                value_type* p =
                    (value_type*)m_rbuf->row_ptr(r.x1, y, len) + (r.x1 << 2);
                do
                {
                    f(p);
                    p += 4;
                }
                while(--len);
            }
        }
    }

    //--------------------------------------------------------------------
    void premultiply()
    {
        for_each_pixel(multiplier_rgba<color_type, order_type>::premultiply);
    }

    //--------------------------------------------------------------------
    void demultiply()
    {
        for_each_pixel(multiplier_rgba<color_type, order_type>::demultiply);
    }

    //--------------------------------------------------------------------
    template<class GammaLut> void apply_gamma_dir(const GammaLut& g)
    {
        for_each_pixel(apply_gamma_dir_rgba<color_type, order_type, GammaLut>(g));
    }

    //--------------------------------------------------------------------
    template<class GammaLut> void apply_gamma_inv(const GammaLut& g)
    {
        for_each_pixel(apply_gamma_inv_rgba<color_type, order_type, GammaLut>(g));
    }

    //--------------------------------------------------------------------
    template<class RenBuf2> void copy_from(const RenBuf2& from,
                                           int xdst, int ydst,
                                           int xsrc, int ysrc,
                                           unsigned len)
    {
        const int8u* p = from.row_ptr(ysrc);
        if(p)
        {
            memmove(m_rbuf->row_ptr(xdst, ydst, len) + xdst * pix_width,
                    p + xsrc * pix_width,
                    len * pix_width);
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from(const SrcPixelFormatRenderer& from,
                    int xdst, int ydst,
                    int xsrc, int ysrc,
                    unsigned len,
                    int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::order_type src_order;
        const value_type* psrc = (const value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            psrc += xsrc << 2;
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);

            int incp = 4;
            if(xdst > xsrc)
            {
                psrc += (len-1) << 2;
                pdst += (len-1) << 2;
                incp = -4;
            }

            do
            {
                blender_type::blend_pix(m_comp_op,
                                        pdst,
                                        psrc[src_order::R],
                                        psrc[src_order::G],
                                        psrc[src_order::B],
                                        psrc[src_order::A],
                                        cover);
                psrc += incp;
                pdst += incp;
            }
            while(--len);
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from_color(const SrcPixelFormatRenderer& from,
                          const color_type& color,
                          int xdst, int ydst,
                          int /*xsrc*/, int ysrc,
                          unsigned len,
                          int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::value_type src_value_type;
        const src_value_type* psrc = (src_value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);
            do
            {
                blender_type::blend_pix(m_comp_op,
                                        pdst,
                                        color.r, color.g, color.b, color.a,
                                        (*psrc * cover + base_mask) >> base_shift);
                ++psrc;
                pdst += 4;
            }
            while(--len);
        }
    }

    //--------------------------------------------------------------------
    template<class SrcPixelFormatRenderer>
    void blend_from_lut(const SrcPixelFormatRenderer& from,
                        const color_type* color_lut,
                        int xdst, int ydst,
                        int /*xsrc*/, int ysrc,
                        unsigned len,
                        int8u cover)
    {
        typedef typename SrcPixelFormatRenderer::value_type src_value_type;
        const src_value_type* psrc = (src_value_type*)from.row_ptr(ysrc);
        if(psrc)
        {
            value_type* pdst =
                (value_type*)m_rbuf->row_ptr(xdst, ydst, len) + (xdst << 2);
            do
            {
                const color_type& color = color_lut[*psrc];
                blender_type::blend_pix(m_comp_op,
                                        pdst,
                                        color.r, color.g, color.b, color.a,
                                        cover);
                ++psrc;
                pdst += 4;
            }
            while(--len);
        }
    }

private:
    rbuf_type* m_rbuf;
    unsigned m_comp_op;
};



extern template struct MAPNIK_DECL comp_op_rgba_hue<agg::rgba8, agg::order_rgba>;
extern template struct MAPNIK_DECL comp_op_rgba_saturation<agg::rgba8, agg::order_rgba>;
extern template struct MAPNIK_DECL comp_op_rgba_color<agg::rgba8, agg::order_rgba>;
extern template struct MAPNIK_DECL comp_op_rgba_value<agg::rgba8, agg::order_rgba>;

//-----------------------------------------------------------------------
typedef blender_rgba<rgba8, order_rgba> blender_rgba32; //----blender_rgba32
typedef blender_rgba<rgba8, order_argb> blender_argb32; //----blender_argb32
typedef blender_rgba<rgba8, order_abgr> blender_abgr32; //----blender_abgr32
typedef blender_rgba<rgba8, order_bgra> blender_bgra32; //----blender_bgra32

typedef blender_rgba_pre<rgba8, order_rgba> blender_rgba32_pre; //----blender_rgba32_pre
typedef blender_rgba_pre<rgba8, order_argb> blender_argb32_pre; //----blender_argb32_pre
typedef blender_rgba_pre<rgba8, order_abgr> blender_abgr32_pre; //----blender_abgr32_pre
typedef blender_rgba_pre<rgba8, order_bgra> blender_bgra32_pre; //----blender_bgra32_pre

typedef blender_rgba_plain<rgba8, order_rgba> blender_rgba32_plain; //----blender_rgba32_plain
typedef blender_rgba_plain<rgba8, order_argb> blender_argb32_plain; //----blender_argb32_plain
typedef blender_rgba_plain<rgba8, order_abgr> blender_abgr32_plain; //----blender_abgr32_plain
typedef blender_rgba_plain<rgba8, order_bgra> blender_bgra32_plain; //----blender_bgra32_plain

typedef blender_rgba<rgba16, order_rgba> blender_rgba64; //----blender_rgba64
typedef blender_rgba<rgba16, order_argb> blender_argb64; //----blender_argb64
typedef blender_rgba<rgba16, order_abgr> blender_abgr64; //----blender_abgr64
typedef blender_rgba<rgba16, order_bgra> blender_bgra64; //----blender_bgra64

typedef blender_rgba_pre<rgba16, order_rgba> blender_rgba64_pre; //----blender_rgba64_pre
typedef blender_rgba_pre<rgba16, order_argb> blender_argb64_pre; //----blender_argb64_pre
typedef blender_rgba_pre<rgba16, order_abgr> blender_abgr64_pre; //----blender_abgr64_pre
typedef blender_rgba_pre<rgba16, order_bgra> blender_bgra64_pre; //----blender_bgra64_pre


//-----------------------------------------------------------------------
typedef int32u pixel32_type;
typedef pixfmt_alpha_blend_rgba<blender_rgba32, rendering_buffer, pixel32_type> pixfmt_rgba32; //----pixfmt_rgba32
typedef pixfmt_alpha_blend_rgba<blender_argb32, rendering_buffer, pixel32_type> pixfmt_argb32; //----pixfmt_argb32
typedef pixfmt_alpha_blend_rgba<blender_abgr32, rendering_buffer, pixel32_type> pixfmt_abgr32; //----pixfmt_abgr32
typedef pixfmt_alpha_blend_rgba<blender_bgra32, rendering_buffer, pixel32_type> pixfmt_bgra32; //----pixfmt_bgra32

typedef pixfmt_alpha_blend_rgba<blender_rgba32_pre, rendering_buffer, pixel32_type> pixfmt_rgba32_pre; //----pixfmt_rgba32_pre
typedef pixfmt_alpha_blend_rgba<blender_argb32_pre, rendering_buffer, pixel32_type> pixfmt_argb32_pre; //----pixfmt_argb32_pre
typedef pixfmt_alpha_blend_rgba<blender_abgr32_pre, rendering_buffer, pixel32_type> pixfmt_abgr32_pre; //----pixfmt_abgr32_pre
typedef pixfmt_alpha_blend_rgba<blender_bgra32_pre, rendering_buffer, pixel32_type> pixfmt_bgra32_pre; //----pixfmt_bgra32_pre

typedef pixfmt_alpha_blend_rgba<blender_rgba32_plain, rendering_buffer, pixel32_type> pixfmt_rgba32_plain; //----pixfmt_rgba32_plain
typedef pixfmt_alpha_blend_rgba<blender_argb32_plain, rendering_buffer, pixel32_type> pixfmt_argb32_plain; //----pixfmt_argb32_plain
typedef pixfmt_alpha_blend_rgba<blender_abgr32_plain, rendering_buffer, pixel32_type> pixfmt_abgr32_plain; //----pixfmt_abgr32_plain
typedef pixfmt_alpha_blend_rgba<blender_bgra32_plain, rendering_buffer, pixel32_type> pixfmt_bgra32_plain; //----pixfmt_bgra32_plain

struct  pixel64_type { int16u c[4]; };
typedef pixfmt_alpha_blend_rgba<blender_rgba64, rendering_buffer, pixel64_type> pixfmt_rgba64; //----pixfmt_rgba64
typedef pixfmt_alpha_blend_rgba<blender_argb64, rendering_buffer, pixel64_type> pixfmt_argb64; //----pixfmt_argb64
typedef pixfmt_alpha_blend_rgba<blender_abgr64, rendering_buffer, pixel64_type> pixfmt_abgr64; //----pixfmt_abgr64
typedef pixfmt_alpha_blend_rgba<blender_bgra64, rendering_buffer, pixel64_type> pixfmt_bgra64; //----pixfmt_bgra64

typedef pixfmt_alpha_blend_rgba<blender_rgba64_pre, rendering_buffer, pixel64_type> pixfmt_rgba64_pre; //----pixfmt_rgba64_pre
typedef pixfmt_alpha_blend_rgba<blender_argb64_pre, rendering_buffer, pixel64_type> pixfmt_argb64_pre; //----pixfmt_argb64_pre
typedef pixfmt_alpha_blend_rgba<blender_abgr64_pre, rendering_buffer, pixel64_type> pixfmt_abgr64_pre; //----pixfmt_abgr64_pre
typedef pixfmt_alpha_blend_rgba<blender_bgra64_pre, rendering_buffer, pixel64_type> pixfmt_bgra64_pre; //----pixfmt_bgra64_pre
}

#endif