mapnik/agg/include/agg_font_cache_manager.h

//----------------------------------------------------------------------------
// 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
//----------------------------------------------------------------------------

#ifndef AGG_FONT_CACHE_MANAGER_INCLUDED
#define AGG_FONT_CACHE_MANAGER_INCLUDED

#include <string.h>
#include "agg_array.h"

namespace agg
{

    //---------------------------------------------------------glyph_data_type
    enum glyph_data_type
    {
        glyph_data_invalid = 0,
        glyph_data_mono    = 1,
        glyph_data_gray8   = 2,
        glyph_data_outline = 3
    };


    //-------------------------------------------------------------glyph_cache
    struct glyph_cache
    {
        unsigned        glyph_index;
        int8u*          data;
        unsigned        data_size;
        glyph_data_type data_type;
        rect_i          bounds;
        double          advance_x;
        double          advance_y;
    };


    //--------------------------------------------------------------font_cache
    class font_cache
    {
    public:
        enum block_size_e { block_size = 16384-16 };

        //--------------------------------------------------------------------
        font_cache() : 
            m_allocator(block_size),
            m_font_signature(0)
        {}

        //--------------------------------------------------------------------
        void signature(const char* font_signature)
        {
            m_font_signature = (char*)m_allocator.allocate(strlen(font_signature) + 1);
            strcpy(m_font_signature, font_signature);
            memset(m_glyphs, 0, sizeof(m_glyphs));
        }

        //--------------------------------------------------------------------
        bool font_is(const char* font_signature) const
        {
            return strcmp(font_signature, m_font_signature) == 0;
        }

        //--------------------------------------------------------------------
        const glyph_cache* find_glyph(unsigned glyph_code) const
        {
            unsigned msb = (glyph_code >> 8) & 0xFF;
            if(m_glyphs[msb]) 
            {
                return m_glyphs[msb][glyph_code & 0xFF];
            }
            return 0;
        }

        //--------------------------------------------------------------------
        glyph_cache* cache_glyph(unsigned        glyph_code, 
                                 unsigned        glyph_index,
                                 unsigned        data_size,
                                 glyph_data_type data_type,
                                 const rect_i&   bounds,
                                 double          advance_x,
                                 double          advance_y)
        {
            unsigned msb = (glyph_code >> 8) & 0xFF;
            if(m_glyphs[msb] == 0)
            {
                m_glyphs[msb] = 
                    (glyph_cache**)m_allocator.allocate(sizeof(glyph_cache*) * 256, 
                                                        sizeof(glyph_cache*));
                memset(m_glyphs[msb], 0, sizeof(glyph_cache*) * 256);
            }

            unsigned lsb = glyph_code & 0xFF;
            if(m_glyphs[msb][lsb]) return 0; // Already exists, do not overwrite

            glyph_cache* glyph = 
                (glyph_cache*)m_allocator.allocate(sizeof(glyph_cache),
                                                   sizeof(double));

            glyph->glyph_index        = glyph_index;
            glyph->data               = m_allocator.allocate(data_size);
            glyph->data_size          = data_size;
            glyph->data_type          = data_type;
            glyph->bounds             = bounds;
            glyph->advance_x          = advance_x;
            glyph->advance_y          = advance_y;
            return m_glyphs[msb][lsb] = glyph;
        }

    private:
        block_allocator m_allocator;
        glyph_cache**   m_glyphs[256];
        char*           m_font_signature;
    };






    
    //---------------------------------------------------------font_cache_pool
    class font_cache_pool
    {
    public:
        //--------------------------------------------------------------------
        ~font_cache_pool()
        {
            unsigned i;
            for(i = 0; i < m_num_fonts; ++i)
            {
                obj_allocator<font_cache>::deallocate(m_fonts[i]);
            }
            pod_allocator<font_cache*>::deallocate(m_fonts, m_max_fonts);
        }

        //--------------------------------------------------------------------
        font_cache_pool(unsigned max_fonts=32) : 
            m_fonts(pod_allocator<font_cache*>::allocate(max_fonts)),
            m_max_fonts(max_fonts),
            m_num_fonts(0),
            m_cur_font(0)
        {}


        //--------------------------------------------------------------------
        void font(const char* font_signature, bool reset_cache = false)
        {
            int idx = find_font(font_signature);
            if(idx >= 0)
            {
                if(reset_cache)
                {
                    obj_allocator<font_cache>::deallocate(m_fonts[idx]);
                    m_fonts[idx] = obj_allocator<font_cache>::allocate();
                    m_fonts[idx]->signature(font_signature);
                }
                m_cur_font = m_fonts[idx];
            }
            else
            {
                if(m_num_fonts >= m_max_fonts)
                {
                    obj_allocator<font_cache>::deallocate(m_fonts[0]);
                    memcpy(m_fonts, 
                           m_fonts + 1, 
                           (m_max_fonts - 1) * sizeof(font_cache*));
                    m_num_fonts = m_max_fonts - 1;
                }
                m_fonts[m_num_fonts] = obj_allocator<font_cache>::allocate();
                m_fonts[m_num_fonts]->signature(font_signature);
                m_cur_font = m_fonts[m_num_fonts];
                ++m_num_fonts;
            }
        }

        //--------------------------------------------------------------------
        const font_cache* font() const
        {
            return m_cur_font;
        }

        //--------------------------------------------------------------------
        const glyph_cache* find_glyph(unsigned glyph_code) const
        {
            if(m_cur_font) return m_cur_font->find_glyph(glyph_code);
            return 0;
        }

        //--------------------------------------------------------------------
        glyph_cache* cache_glyph(unsigned        glyph_code, 
                                 unsigned        glyph_index,
                                 unsigned        data_size,
                                 glyph_data_type data_type,
                                 const rect_i&   bounds,
                                 double          advance_x,
                                 double          advance_y)
        {
            if(m_cur_font) 
            {
                return m_cur_font->cache_glyph(glyph_code,
                                               glyph_index,
                                               data_size,
                                               data_type,
                                               bounds,
                                               advance_x,
                                               advance_y);
            }
            return 0;
        }


        //--------------------------------------------------------------------
        int find_font(const char* font_signature)
        {
            unsigned i;
            for(i = 0; i < m_num_fonts; i++)
            {
                if(m_fonts[i]->font_is(font_signature)) return int(i);
            }
            return -1;
        }

    private:
        font_cache** m_fonts;
        unsigned     m_max_fonts;
        unsigned     m_num_fonts;
        font_cache*  m_cur_font;
    };




    //------------------------------------------------------------------------
    enum glyph_rendering
    {
        glyph_ren_native_mono,
        glyph_ren_native_gray8,
        glyph_ren_outline,
        glyph_ren_agg_mono,
        glyph_ren_agg_gray8
    };




    //------------------------------------------------------font_cache_manager
    template<class FontEngine> class font_cache_manager
    {
    public:
        typedef FontEngine font_engine_type;
        typedef font_cache_manager<FontEngine> self_type;
        typedef typename font_engine_type::path_adaptor_type   path_adaptor_type;
        typedef typename font_engine_type::gray8_adaptor_type  gray8_adaptor_type;
        typedef typename gray8_adaptor_type::embedded_scanline gray8_scanline_type;
        typedef typename font_engine_type::mono_adaptor_type   mono_adaptor_type;
        typedef typename mono_adaptor_type::embedded_scanline  mono_scanline_type;

        //--------------------------------------------------------------------
        font_cache_manager(font_engine_type& engine, unsigned max_fonts=32) :
            m_fonts(max_fonts),
            m_engine(engine),
            m_change_stamp(-1),
            m_prev_glyph(0),
            m_last_glyph(0)
        {}

        //--------------------------------------------------------------------
        void reset_last_glyph()
        {
            m_prev_glyph = m_last_glyph = 0;
        }

        //--------------------------------------------------------------------
        const glyph_cache* glyph(unsigned glyph_code)
        {
            synchronize();
            const glyph_cache* gl = m_fonts.find_glyph(glyph_code);
            if(gl) 
            {
                m_prev_glyph = m_last_glyph;
                return m_last_glyph = gl;
            }
            else
            {
                if(m_engine.prepare_glyph(glyph_code))
                {
                    m_prev_glyph = m_last_glyph;
                    m_last_glyph = m_fonts.cache_glyph(glyph_code, 
                                                       m_engine.glyph_index(),
                                                       m_engine.data_size(),
                                                       m_engine.data_type(),
                                                       m_engine.bounds(),
                                                       m_engine.advance_x(),
                                                       m_engine.advance_y());
                    m_engine.write_glyph_to(m_last_glyph->data);
                    return m_last_glyph;
                }
            }
            return 0;
        }

        //--------------------------------------------------------------------
        void init_embedded_adaptors(const glyph_cache* gl, 
                                    double x, double y, 
                                    double scale=1.0)
        {
            if(gl)
            {
                switch(gl->data_type)
                {
                default: return;
                case glyph_data_mono:
                    m_mono_adaptor.init(gl->data, gl->data_size, x, y);
                    break;

                case glyph_data_gray8:
                    m_gray8_adaptor.init(gl->data, gl->data_size, x, y);
                    break;

                case glyph_data_outline:
                    m_path_adaptor.init(gl->data, gl->data_size, x, y, scale);
                    break;
                }
            }
        }


        //--------------------------------------------------------------------
        path_adaptor_type&   path_adaptor()   { return m_path_adaptor;   }
        gray8_adaptor_type&  gray8_adaptor()  { return m_gray8_adaptor;  }
        gray8_scanline_type& gray8_scanline() { return m_gray8_scanline; }
        mono_adaptor_type&   mono_adaptor()   { return m_mono_adaptor;   }
        mono_scanline_type&  mono_scanline()  { return m_mono_scanline;  }

        //--------------------------------------------------------------------
        const glyph_cache* perv_glyph() const { return m_prev_glyph; }
        const glyph_cache* last_glyph() const { return m_last_glyph; }

        //--------------------------------------------------------------------
        bool add_kerning(double* x, double* y)
        {
            if(m_prev_glyph && m_last_glyph)
            {
                return m_engine.add_kerning(m_prev_glyph->glyph_index, 
                                            m_last_glyph->glyph_index,
                                            x, y);
            }
            return false;
        }

        //--------------------------------------------------------------------
        void precache(unsigned from, unsigned to)
        {
            for(; from <= to; ++from) glyph(from);
        }

        //--------------------------------------------------------------------
        void reset_cache()
        {
            m_fonts.font(m_engine.font_signature(), true);
            m_change_stamp = m_engine.change_stamp();
            m_prev_glyph = m_last_glyph = 0;
        }

    private:
        //--------------------------------------------------------------------
        font_cache_manager(const self_type&);
        const self_type& operator = (const self_type&);

        //--------------------------------------------------------------------
        void synchronize()
        {
            if(m_change_stamp != m_engine.change_stamp())
            {
                m_fonts.font(m_engine.font_signature());
                m_change_stamp = m_engine.change_stamp();
                m_prev_glyph = m_last_glyph = 0;
            }
        }

        font_cache_pool     m_fonts;
        font_engine_type&   m_engine;
        int                 m_change_stamp;
        double              m_dx;
        double              m_dy;
        const glyph_cache*  m_prev_glyph;
        const glyph_cache*  m_last_glyph;
        path_adaptor_type   m_path_adaptor;
        gray8_adaptor_type  m_gray8_adaptor;
        gray8_scanline_type m_gray8_scanline;
        mono_adaptor_type   m_mono_adaptor;
        mono_scanline_type  m_mono_scanline;
    };

}

#endif