mapnik/src/agg_renderer.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/
//$Id$

// mapnik
#include <mapnik/agg_renderer.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/image_cache.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/placement_finder.hpp>
#include <mapnik/markers_converter.hpp>
#include <mapnik/arrow.hpp>
#include <mapnik/config_error.hpp>
#include <mapnik/font_set.hpp>
#include <mapnik/path_expression_grammar.hpp>
#include <mapnik/text_path.hpp>

// agg
#define AGG_RENDERING_BUFFER row_ptr_cache<int8u>
#include "agg_rendering_buffer.h"
#include "agg_pixfmt_rgba.h"
#include "agg_rasterizer_scanline_aa.h"
#include "agg_basics.h"
#include "agg_scanline_p.h"
#include "agg_scanline_u.h"
#include "agg_renderer_scanline.h"
#include "agg_path_storage.h"
#include "agg_span_allocator.h"
#include "agg_span_pattern_rgba.h"
#include "agg_image_accessors.h"
#include "agg_conv_stroke.h"
#include "agg_conv_dash.h"
#include "agg_conv_contour.h"
#include "agg_conv_clip_polyline.h"
#include "agg_vcgen_stroke.h"
#include "agg_conv_adaptor_vcgen.h"
#include "agg_conv_smooth_poly1.h"
#include "agg_conv_marker.h"
#include "agg_vcgen_markers_term.h"
#include "agg_renderer_outline_aa.h"
#include "agg_rasterizer_outline_aa.h"
#include "agg_rasterizer_outline.h"
#include "agg_renderer_outline_image.h"
#include "agg_span_allocator.h"
#include "agg_span_pattern_rgba.h"
#include "agg_renderer_scanline.h"
#include "agg_pattern_filters_rgba.h"
#include "agg_renderer_outline_image.h"
#include "agg_vpgen_clip_polyline.h"
#include "agg_arrowhead.h"

// boost
#include <boost/utility.hpp>
#include <boost/tuple/tuple.hpp>

// stl
#ifdef MAPNIK_DEBUG
#include <iostream>
#endif

#include <cmath>

namespace mapnik
{
class pattern_source : private boost::noncopyable
{
public:
    pattern_source(image_data_32 const& pattern)
	: pattern_(pattern) {}

    unsigned int width() const
    {
	return pattern_.width();
    }
    unsigned int height() const
    {
	return pattern_.height();
    }
    agg::rgba8 pixel(int x, int y) const
    {
	unsigned c = pattern_(x,y);
	return agg::rgba8(c & 0xff,
			  (c >> 8) & 0xff,
			  (c >> 16) & 0xff,
			  (c >> 24) & 0xff);
    }
private:
    image_data_32 const& pattern_;
};

struct rasterizer :  agg::rasterizer_scanline_aa<>, boost::noncopyable {};

template <typename T>
agg_renderer<T>::agg_renderer(Map const& m, T & pixmap, unsigned offset_x, unsigned offset_y)
    : feature_style_processor<agg_renderer>(m),
      pixmap_(pixmap),
      width_(pixmap_.width()),
      height_(pixmap_.height()),
      t_(m.getWidth(),m.getHeight(),m.getCurrentExtent(),offset_x,offset_y),
      font_engine_(),
      font_manager_(font_engine_),
      detector_(box2d<double>(-m.buffer_size(), -m.buffer_size(), m.getWidth() + m.buffer_size() ,m.getHeight() + m.buffer_size())),
      ras_ptr(new rasterizer)
{
    boost::optional<color> bg = m.background();
    if (bg) pixmap_.set_background(*bg);
#ifdef MAPNIK_DEBUG
    std::clog << "scale=" << m.scale() << "\n";
#endif
}

template <typename T>
agg_renderer<T>::~agg_renderer() {}

template <typename T>
void agg_renderer<T>::start_map_processing(Map const& map)
{
#ifdef MAPNIK_DEBUG
    std::clog << "start map processing bbox="
	      << map.getCurrentExtent() << "\n";
#endif
    ras_ptr->clip_box(0,0,width_,height_);
}

template <typename T>
void agg_renderer<T>::end_map_processing(Map const& )
{
#ifdef MAPNIK_DEBUG
    std::clog << "end map processing\n";
#endif
}

template <typename T>
void agg_renderer<T>::start_layer_processing(layer const& lay)
{
#ifdef MAPNIK_DEBUG
    std::clog << "start layer processing : " << lay.name()  << "\n";
    std::clog << "datasource = " << lay.datasource().get() << "\n";
#endif
    if (lay.clear_label_cache())
    {
	detector_.clear();
    }
}

template <typename T>
void agg_renderer<T>::end_layer_processing(layer const&)
{
#ifdef MAPNIK_DEBUG
    std::clog << "end layer processing\n";
#endif
}

template <typename T>
void agg_renderer<T>::process(polygon_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> ren_base;
    typedef agg::renderer_scanline_aa_solid<ren_base> renderer;

    color const& fill_ = sym.get_fill();
    agg::scanline_u8 sl;

    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);

    ren_base renb(pixf);
    unsigned r=fill_.red();
    unsigned g=fill_.green();
    unsigned b=fill_.blue();
    unsigned a=fill_.alpha();
    renderer ren(renb);

    ras_ptr->reset();
    ras_ptr->gamma(agg::gamma_linear(0.0, sym.get_gamma()));

    for (unsigned i=0;i<feature.num_geometries();++i)
    {
	geometry2d const& geom=feature.get_geometry(i);
	if (geom.num_points() > 2)
	{
            path_type path(t_,geom,prj_trans);
            ras_ptr->add_path(path);
	}
    }
    ren.color(agg::rgba8(r, g, b, int(a * sym.get_opacity())));
    agg::render_scanlines(*ras_ptr, sl, ren);
}

typedef boost::tuple<double,double,double,double> segment_t;
bool y_order(segment_t const& first,segment_t const& second)
{
    double miny0 = std::min(first.get<1>(),first.get<3>());
    double miny1 = std::min(second.get<1>(),second.get<3>());
    return  miny0 > miny1;
}

template <typename T>
void agg_renderer<T>::process(building_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;
    typedef  coord_transform3<CoordTransform,geometry2d> path_type_roof;
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> ren_base;
    typedef agg::renderer_scanline_aa_solid<ren_base> renderer;

    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);
    ren_base renb(pixf);

    color const& fill_  = sym.get_fill();
    unsigned r=fill_.red();
    unsigned g=fill_.green();
    unsigned b=fill_.blue();
    unsigned a=fill_.alpha();
    renderer ren(renb);
    agg::scanline_u8 sl;

    ras_ptr->reset();
    ras_ptr->gamma(agg::gamma_linear());
    
    double height = 0.7071 * sym.height(); // height in meters

    for (unsigned i=0;i<feature.num_geometries();++i)
    {
	geometry2d const& geom = feature.get_geometry(i);
	if (geom.num_points() > 2)
	{
            boost::scoped_ptr<geometry2d> frame(new line_string_impl);
            boost::scoped_ptr<geometry2d> roof(new polygon_impl);
            std::deque<segment_t> face_segments;
            double x0(0);
            double y0(0);
            unsigned cm = geom.vertex(&x0,&y0);
            for (unsigned j=1;j<geom.num_points();++j)
            {
		double x,y;
		cm = geom.vertex(&x,&y);
		if (cm == SEG_MOVETO)
		{
		    frame->move_to(x,y);
		}
		else if (cm == SEG_LINETO)
		{
		    frame->line_to(x,y);
		    face_segments.push_back(segment_t(x0,y0,x,y));
		}
		
		x0 = x;
		y0 = y;
            }
            std::sort(face_segments.begin(),face_segments.end(), y_order);
            std::deque<segment_t>::const_iterator itr=face_segments.begin();
            for (;itr!=face_segments.end();++itr)
            {
		boost::scoped_ptr<geometry2d> faces(new polygon_impl);
		faces->move_to(itr->get<0>(),itr->get<1>());
		faces->line_to(itr->get<2>(),itr->get<3>());
		faces->line_to(itr->get<2>(),itr->get<3>() + height);
		faces->line_to(itr->get<0>(),itr->get<1>() + height);

		path_type faces_path (t_,*faces,prj_trans);
		ras_ptr->add_path(faces_path);
		ren.color(agg::rgba8(int(r*0.8), int(g*0.8), int(b*0.8), int(a * sym.get_opacity())));
		agg::render_scanlines(*ras_ptr, sl, ren);
		ras_ptr->reset();

		frame->move_to(itr->get<0>(),itr->get<1>());
		frame->line_to(itr->get<0>(),itr->get<1>()+height);
            }

            geom.rewind(0);
            for (unsigned j=0;j<geom.num_points();++j)
            {
		double x,y;
		unsigned cm = geom.vertex(&x,&y);
		if (cm == SEG_MOVETO)
		{
		    frame->move_to(x,y+height);
		    roof->move_to(x,y+height);
		}
		else if (cm == SEG_LINETO)
		{
		    frame->line_to(x,y+height);
		    roof->line_to(x,y+height);
		}
            }
            path_type path(t_,*frame,prj_trans);
            agg::conv_stroke<path_type>  stroke(path);
            ras_ptr->add_path(stroke);
            ren.color(agg::rgba8(r * 0.8, g * 0.8 , b * 0.8, int(255 * sym.get_opacity())));
            agg::render_scanlines(*ras_ptr, sl, ren);
            ras_ptr->reset();

            path_type roof_path (t_,*roof,prj_trans);
            ras_ptr->add_path(roof_path);
            ren.color(agg::rgba8(r, g, b, int(a * sym.get_opacity())));
            agg::render_scanlines(*ras_ptr, sl, ren);
	}
    }
}

template <typename T>
void agg_renderer<T>::process(line_symbolizer const& sym,
                              Feature const& feature,
                              proj_transform const& prj_trans)
{
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> ren_base;
    typedef coord_transform2<CoordTransform,geometry2d> path_type;
    typedef agg::renderer_outline_aa<ren_base> renderer_oaa;
    typedef agg::rasterizer_outline_aa<renderer_oaa> rasterizer_outline_aa;
    typedef agg::renderer_scanline_aa_solid<ren_base> renderer;

    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);

    ren_base renb(pixf);
    mapnik::stroke const&  stroke_ = sym.get_stroke();
    color const& col = stroke_.get_color();
    unsigned r=col.red();
    unsigned g=col.green();
    unsigned b=col.blue();
    unsigned a=col.alpha();
    renderer ren(renb);
    ras_ptr->reset();
    ras_ptr->gamma(agg::gamma_linear());
    
    agg::scanline_p8 sl;

    for (unsigned i=0;i<feature.num_geometries();++i)
    {
	geometry2d const& geom = feature.get_geometry(i);
	if (geom.num_points() > 1)
	{
            path_type path(t_,geom,prj_trans);

            if (stroke_.has_dash())
            {
		agg::conv_dash<path_type> dash(path);
		dash_array const& d = stroke_.get_dash_array();
		dash_array::const_iterator itr = d.begin();
		dash_array::const_iterator end = d.end();
		for (;itr != end;++itr)
		{
		    dash.add_dash(itr->first, itr->second);
		}

		agg::conv_stroke<agg::conv_dash<path_type > > stroke(dash);

		line_join_e join=stroke_.get_line_join();
		if ( join == MITER_JOIN)
		    stroke.generator().line_join(agg::miter_join);
		else if( join == MITER_REVERT_JOIN)
		    stroke.generator().line_join(agg::miter_join);
		else if( join == ROUND_JOIN)
		    stroke.generator().line_join(agg::round_join);
		else
		    stroke.generator().line_join(agg::bevel_join);

		line_cap_e cap=stroke_.get_line_cap();
		if (cap == BUTT_CAP)
		    stroke.generator().line_cap(agg::butt_cap);
		else if (cap == SQUARE_CAP)
		    stroke.generator().line_cap(agg::square_cap);
		else
		    stroke.generator().line_cap(agg::round_cap);

		stroke.generator().miter_limit(4.0);
		stroke.generator().width(stroke_.get_width());
		
		ras_ptr->add_path(stroke);

            }
            else
            {
		agg::conv_stroke<path_type>  stroke(path);
		line_join_e join=stroke_.get_line_join();
		if ( join == MITER_JOIN)
		    stroke.generator().line_join(agg::miter_join);
		else if( join == MITER_REVERT_JOIN)
		    stroke.generator().line_join(agg::miter_join);
		else if( join == ROUND_JOIN)
		    stroke.generator().line_join(agg::round_join);
		else
		    stroke.generator().line_join(agg::bevel_join);

		line_cap_e cap=stroke_.get_line_cap();
		if (cap == BUTT_CAP)
		    stroke.generator().line_cap(agg::butt_cap);
		else if (cap == SQUARE_CAP)
		    stroke.generator().line_cap(agg::square_cap);
		else
		    stroke.generator().line_cap(agg::round_cap);

		stroke.generator().miter_limit(4.0);
		stroke.generator().width(stroke_.get_width());
		ras_ptr->add_path(stroke);
            }
	}
    }
    ren.color(agg::rgba8(r, g, b, int(a*stroke_.get_opacity())));
    agg::render_scanlines(*ras_ptr, sl, ren);
}

template <typename T>
void agg_renderer<T>::process(point_symbolizer const& sym,
                              Feature const& feature,
                              proj_transform const& prj_trans)
{
    double x;
    double y;
    double z=0;
    
    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> data;
    
    if ( filename.empty() )
    {
        // default OGC 4x4 black square
        data = boost::optional<mapnik::image_ptr>(new image_data_32(4,4));
        (*data)->set(0xff000000);
    }
    else
    {
        data = mapnik::image_cache::instance()->find(filename,true);
    }
    
    if ( data )
    {
	for (unsigned i=0;i<feature.num_geometries();++i)
	{
            geometry2d const& geom = feature.get_geometry(i);

            geom.label_position(&x,&y);
            prj_trans.backward(x,y,z);
            t_.forward(&x,&y);
            int w = (*data)->width();
            int h = (*data)->height();
            int px=int(floor(x - 0.5 * w));
            int py=int(floor(y - 0.5 * h));
            box2d<double> label_ext (floor(x - 0.5 * w),
				     floor(y - 0.5 * h),
				     ceil (x + 0.5 * w),
				     ceil (y + 0.5 * h));
            if (sym.get_allow_overlap() ||
                detector_.has_placement(label_ext))
            {
		pixmap_.set_rectangle_alpha2(*(*data),px,py,sym.get_opacity());
		detector_.insert(label_ext);
            }
	}
    }
}

template <typename T>
void  agg_renderer<T>::process(shield_symbolizer const& sym,
			       Feature const& feature,
			       proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;

    UnicodeString text;
    if( sym.get_no_text() )
	text = UnicodeString( " " );  // TODO: fix->use 'space' as the text to render
    else
    {
	expression_ptr name_expr = sym.get_name();
	if (!name_expr) return;
	value_type result = boost::apply_visitor(evaluate<Feature,value_type>(feature),*name_expr);
	text = result.to_unicode();
    }
    
    if ( sym.get_text_convert() == TOUPPER)
    {
	text = text.toUpper();
    }
    else if ( sym.get_text_convert() == TOLOWER)
    {
	text = text.toLower();
    }
    
    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> data = mapnik::image_cache::instance()->find(filename,true);
    
    if (text.length() > 0 && data)
    {
	face_set_ptr faces;

	if (sym.get_fontset().size() > 0)
	{
            faces = font_manager_.get_face_set(sym.get_fontset());
	}
	else
	{
            faces = font_manager_.get_face_set(sym.get_face_name());
	}

	if (faces->size() > 0)
	{
            text_renderer<T> ren(pixmap_, faces);

            ren.set_pixel_size(sym.get_text_size());
            ren.set_fill(sym.get_fill());
            ren.set_halo_fill(sym.get_halo_fill());
            ren.set_halo_radius(sym.get_halo_radius());

            placement_finder<label_collision_detector4> finder(detector_);

            string_info info(text);

            faces->get_string_info(info);


            int w = (*data)->width();
            int h = (*data)->height();

            unsigned num_geom = feature.num_geometries();
            for (unsigned i=0;i<num_geom;++i)
            {
		geometry2d const& geom = feature.get_geometry(i);
		if (geom.num_points() > 0 )
		{
		    path_type path(t_,geom,prj_trans);

		    label_placement_enum how_placed = sym.get_label_placement();
		    if (how_placed == POINT_PLACEMENT || how_placed == VERTEX_PLACEMENT)
		    {
			// for every vertex, try and place a shield/text
			geom.rewind(0);
			for( unsigned jj = 0; jj < geom.num_points(); jj++ )
			{
			    double label_x;
			    double label_y;
			    double z=0.0;
			    placement text_placement(info, sym, w, h, false);
			    text_placement.avoid_edges = sym.get_avoid_edges();
			    text_placement.allow_overlap = sym.get_allow_overlap();
			    if( how_placed == VERTEX_PLACEMENT )
				geom.vertex(&label_x,&label_y);  // by vertex
			    else
				geom.label_position(&label_x, &label_y);  // by middle of line or by point
			    prj_trans.backward(label_x,label_y, z);
			    t_.forward(&label_x,&label_y);

			    finder.find_point_placement( text_placement,label_x,label_y,0.0,sym.get_vertical_alignment(),sym.get_line_spacing(),
							 sym.get_character_spacing(),sym.get_horizontal_alignment(),sym.get_justify_alignment() );

			    // check to see if image overlaps anything too, there is only ever 1 placement found for points and verticies
			    if( text_placement.placements.size() > 0)
			    {
				double x = text_placement.placements[0].starting_x;
				double y = text_placement.placements[0].starting_y;
				int px;
				int py;
				box2d<double> label_ext;

				if( !sym.get_unlock_image() )
				{  // center image at text center position
				    // remove displacement from image label
				    position pos = sym.get_displacement();
				    double lx = x - boost::get<0>(pos);
				    double ly = y - boost::get<1>(pos);
				    px=int(floor(lx - (0.5 * w))) ;
				    py=int(floor(ly - (0.5 * h))) ;
				    label_ext.init( floor(lx - 0.5 * w), floor(ly - 0.5 * h), ceil (lx + 0.5 * w), ceil (ly + 0.5 * h) );
				}
				else
				{  // center image at reference location
				    px=int(floor(label_x - 0.5 * w));
				    py=int(floor(label_y - 0.5 * h));
				    label_ext.init( floor(label_x - 0.5 * w), floor(label_y - 0.5 * h), ceil (label_x + 0.5 * w), ceil (label_y + 0.5 * h));
				}

				if ( sym.get_allow_overlap() || detector_.has_placement(label_ext) )
				{
				    //pixmap_.set_rectangle_alpha(px,py,*data);
				    pixmap_.set_rectangle_alpha2(*(*data),px,py,float(sym.get_opacity()));
				    box2d<double> dim = ren.prepare_glyphs(&text_placement.placements[0]);
				    ren.render(x,y);
				    detector_.insert(label_ext);
				    finder.update_detector(text_placement);
				}
			    }
			}
		    }

		    else if (geom.num_points() > 1 && sym.get_label_placement() == LINE_PLACEMENT)
		    {
			placement text_placement(info, sym, w, h, true);
			text_placement.avoid_edges = sym.get_avoid_edges();
			finder.find_point_placements<path_type>(text_placement,path);

			for (unsigned int ii = 0; ii < text_placement.placements.size(); ++ ii)
			{
			    int w = (*data)->width();
			    int h = (*data)->height();
			    double x = text_placement.placements[ii].starting_x;
			    double y = text_placement.placements[ii].starting_y;
			 
			    int px=int(x - (w/2));
			    int py=int(y - (h/2));
			 
			    pixmap_.set_rectangle_alpha(px,py,*(*data));
			 
			    box2d<double> dim = ren.prepare_glyphs(&text_placement.placements[ii]);
			    ren.render(x,y);
			}
			finder.update_detector(text_placement);
		    }
		}
            }
	}
    }
}

template <typename T>
void  agg_renderer<T>::process(line_pattern_symbolizer const& sym,
                               Feature const& feature,
                               proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;
    typedef agg::line_image_pattern<agg::pattern_filter_bilinear_rgba8> pattern_type;
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> renderer_base;
    typedef agg::renderer_outline_image<renderer_base, pattern_type> renderer_type;
    typedef agg::rasterizer_outline_aa<renderer_type> rasterizer_type;

    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);
    
    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> pat = mapnik::image_cache::instance()->find(filename,true);

    if (!pat) return;
      
    renderer_base ren_base(pixf);
    agg::pattern_filter_bilinear_rgba8 filter;
    pattern_source source(*(*pat));
    pattern_type pattern (filter,source);
    renderer_type ren(ren_base, pattern);
    ren.clip_box(0,0,width_,height_);
    rasterizer_type ras(ren);

    for (unsigned i=0;i<feature.num_geometries();++i)
    {
	geometry2d const& geom = feature.get_geometry(i);
	if (geom.num_points() > 1)
	{
            path_type path(t_,geom,prj_trans);
            ras.add_path(path);
	}
    }
}

template <typename T>
void agg_renderer<T>::process(polygon_pattern_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    typedef coord_transform2<CoordTransform,geometry2d> path_type;
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> ren_base;
    typedef agg::wrap_mode_repeat wrap_x_type;
    typedef agg::wrap_mode_repeat wrap_y_type;
    typedef agg::pixfmt_alpha_blend_rgba<agg::blender_rgba32,
	agg::row_accessor<agg::int8u>, agg::pixel32_type> rendering_buffer;
    typedef agg::image_accessor_wrap<rendering_buffer,
	wrap_x_type,
	wrap_y_type> img_source_type;

    typedef agg::span_pattern_rgba<img_source_type> span_gen_type;

    typedef agg::renderer_scanline_aa<ren_base,
	agg::span_allocator<agg::rgba8>,
	span_gen_type> renderer_type;


    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);
    ren_base renb(pixf);
    
    agg::scanline_u8 sl;
    ras_ptr->reset();
    ras_ptr->gamma(agg::gamma_linear());

    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> pat = mapnik::image_cache::instance()->find(filename,true);

    if (!pat) return;
    
    unsigned w=(*pat)->width();
    unsigned h=(*pat)->height();
    agg::row_accessor<agg::int8u> pattern_rbuf((agg::int8u*)(*pat)->getBytes(),w,h,w*4);
    agg::span_allocator<agg::rgba8> sa;
    agg::pixfmt_alpha_blend_rgba<agg::blender_rgba32,
	agg::row_accessor<agg::int8u>, agg::pixel32_type> pixf_pattern(pattern_rbuf);
    img_source_type img_src(pixf_pattern);
    
    double x0=0,y0=0;
    unsigned num_geometries = feature.num_geometries();
    if (num_geometries>0)
    {
	path_type path(t_,feature.get_geometry(0),prj_trans);
	path.vertex(&x0,&y0);
    }
    unsigned offset_x = unsigned(width_-x0);
    unsigned offset_y = unsigned(height_-y0);
    span_gen_type sg(img_src, offset_x, offset_y);
    renderer_type rp(renb,sa, sg);
    for (unsigned i=0;i<num_geometries;++i)
    {
	geometry2d const& geom = feature.get_geometry(i);
	if (geom.num_points() > 2)
	{
	    path_type path(t_,geom,prj_trans);
	    ras_ptr->add_path(path);
	}
    }
    agg::render_scanlines(*ras_ptr, sl, rp);
}

template <typename T>
void agg_renderer<T>::process(raster_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    raster_ptr const& raster=feature.get_raster();
    if (raster)
    {
    // If there's a colorizer defined, use it to color the raster in-place
    raster_colorizer_ptr colorizer = sym.get_colorizer();
    if (colorizer)
        colorizer->colorize(raster);
	
	box2d<double> ext=t_.forward(raster->ext_);
	
	int start_x = rint(ext.minx());
	int start_y = rint(ext.miny());
	int raster_width = rint(ext.width());
	int raster_height = rint(ext.height());
	int end_x = start_x + raster_width;
	int end_y = start_y + raster_height;
	double err_offs_x = (ext.minx()-start_x + ext.maxx()-end_x)/2;
	double err_offs_y = (ext.miny()-start_y + ext.maxy()-end_y)/2;
	
	if ( raster_width > 0 && raster_height > 0)
	{
	    image_data_32 target(raster_width,raster_height);
	  
	    if (sym.get_scaling() == "fast") {
		scale_image<image_data_32>(target,raster->data_);
	    } else if (sym.get_scaling() == "bilinear"){
		scale_image_bilinear<image_data_32>(target,raster->data_, err_offs_x, err_offs_y);
	    } else if (sym.get_scaling() == "bilinear8"){
		scale_image_bilinear8<image_data_32>(target,raster->data_, err_offs_x, err_offs_y);
	    } else {
		scale_image<image_data_32>(target,raster->data_);
	    }
	    
	    if (sym.get_mode() == "normal"){
		if (sym.get_opacity() == 1.0) {
		    pixmap_.set_rectangle(start_x,start_y,target);
		} else {
		    pixmap_.set_rectangle_alpha2(target,start_x,start_y, sym.get_opacity());
		}
	    } else if (sym.get_mode() == "grain_merge"){
		pixmap_.template merge_rectangle<MergeGrain> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "grain_merge2"){
		pixmap_.template merge_rectangle<MergeGrain2> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "multiply"){
		pixmap_.template merge_rectangle<Multiply> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "multiply2"){
		pixmap_.template merge_rectangle<Multiply2> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "divide"){
		pixmap_.template merge_rectangle<Divide> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "divide2"){
		pixmap_.template merge_rectangle<Divide2> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "screen"){
		pixmap_.template merge_rectangle<Screen> (target,start_x,start_y, sym.get_opacity());
	    } else if (sym.get_mode() == "hard_light"){
		pixmap_.template merge_rectangle<HardLight> (target,start_x,start_y, sym.get_opacity());
	    } else {
		if (sym.get_opacity() == 1.0){
		    pixmap_.set_rectangle(start_x,start_y,target);
		} else {
		    pixmap_.set_rectangle_alpha2(target,start_x,start_y, sym.get_opacity());
		}
	    }
	    // TODO: other modes? (add,diff,sub,...)
	}
    }
}

template <typename T>
void agg_renderer<T>::process(markers_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;
    typedef agg::renderer_base<agg::pixfmt_rgba32_plain> ren_base;
    typedef agg::renderer_scanline_aa_solid<ren_base> renderer;
    arrow arrow_;
    ras_ptr->reset();
    ras_ptr->gamma(agg::gamma_linear());


    agg::scanline_u8 sl;
    agg::rendering_buffer buf(pixmap_.raw_data(),width_,height_, width_ * 4);
    agg::pixfmt_rgba32_plain pixf(buf);
    ren_base renb(pixf);

    unsigned r = 0;// fill_.red();
    unsigned g = 0; //fill_.green();
    unsigned b = 255; //fill_.blue();
    unsigned a = 255; //fill_.alpha();
    renderer ren(renb);
    for (unsigned i=0;i<feature.num_geometries();++i)
    {
	geometry2d const& geom=feature.get_geometry(i);
	if (geom.num_points() > 1)
	{
            path_type path(t_,geom,prj_trans);

            agg::conv_dash <path_type> dash(path);
            dash.add_dash(20.0,200.0);
            markers_converter<agg::conv_dash<path_type>,
		arrow,
		label_collision_detector4>
		marker(dash, arrow_, detector_);
            ras_ptr->add_path(marker);
	}
    }
    ren.color(agg::rgba8(r, g, b, a));
    agg::render_scanlines(*ras_ptr, sl, ren);
}

template <typename T>
void agg_renderer<T>::process(text_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    typedef  coord_transform2<CoordTransform,geometry2d> path_type;

    expression_ptr name_expr = sym.get_name();
    if (!name_expr) return;
    value_type result = boost::apply_visitor(evaluate<Feature,value_type>(feature),*name_expr);
    UnicodeString text = result.to_unicode();
      
    if ( sym.get_text_convert() == TOUPPER)
    {
	text = text.toUpper();
    }
    else if ( sym.get_text_convert() == TOLOWER)
    {
	text = text.toLower();
    }

    if ( text.length() > 0 )
    {
	color const& fill = sym.get_fill();

	face_set_ptr faces;

	if (sym.get_fontset().size() > 0)
	{
            faces = font_manager_.get_face_set(sym.get_fontset());
	}
	else
	{
            faces = font_manager_.get_face_set(sym.get_face_name());
	}

	if (faces->size() > 0)
	{
            text_renderer<T> ren(pixmap_, faces);
            ren.set_pixel_size(sym.get_text_size());
            ren.set_fill(fill);
            ren.set_halo_fill(sym.get_halo_fill());
            ren.set_halo_radius(sym.get_halo_radius());
            ren.set_opacity(sym.get_opacity());

            placement_finder<label_collision_detector4> finder(detector_);

            string_info info(text);

            faces->get_string_info(info);
            unsigned num_geom = feature.num_geometries();
            for (unsigned i=0;i<num_geom;++i)
            {
		geometry2d const& geom = feature.get_geometry(i);
		if (geom.num_points() > 0) // don't bother with empty geometries
		{	    
		    placement text_placement(info,sym);
		    text_placement.avoid_edges = sym.get_avoid_edges();
		    if (sym.get_label_placement() == POINT_PLACEMENT)
		    {
			double label_x, label_y, z=0.0;
			geom.label_position(&label_x, &label_y);
			prj_trans.backward(label_x,label_y, z);
			t_.forward(&label_x,&label_y);

			double angle = 0.0;
			expression_ptr angle_expr = sym.get_orientation();
			if (angle_expr)
			{
			    // apply rotation
			    value_type result = boost::apply_visitor(evaluate<Feature,value_type>(feature),*angle_expr);
			    angle = result.to_double();
			}
			
			finder.find_point_placement(text_placement,label_x,label_y, angle, sym.get_vertical_alignment(),sym.get_line_spacing(),
						    sym.get_character_spacing(),sym.get_horizontal_alignment(),sym.get_justify_alignment());
				
			finder.update_detector(text_placement);
		    }
		    else if ( geom.num_points() > 1 && sym.get_label_placement() == LINE_PLACEMENT)
		    {
			path_type path(t_,geom,prj_trans);
			finder.find_line_placements<path_type>(text_placement,path);
		    }
		    
		    for (unsigned int ii = 0; ii < text_placement.placements.size(); ++ii)
		    {
			double x = text_placement.placements[ii].starting_x;
			double y = text_placement.placements[ii].starting_y;
			box2d<double> dim = ren.prepare_glyphs(&text_placement.placements[ii]);
			ren.render(x,y);
		    }
		}
            }
	}
	else
	{
            throw config_error("Unable to find specified font face '" + sym.get_face_name() + "'");
	}
    }
}

template <typename T>
void agg_renderer<T>::process(glyph_symbolizer const& sym,
			      Feature const& feature,
			      proj_transform const& prj_trans)
{
    face_set_ptr faces = font_manager_.get_face_set(sym.get_face_name());
    if (faces->size() > 0)
    {
        // Get x and y from geometry and translate to pixmap coords.
        double x, y, z=0.0;
        feature.get_geometry(0).label_position(&x, &y);
        prj_trans.backward(x,y,z);
        t_.forward(&x, &y);

        text_renderer<T> ren(pixmap_, faces);

        // set fill and halo colors
        color fill = sym.eval_color(feature);
        ren.set_fill(fill);
        if (fill != color("transparent")) {
            ren.set_halo_fill(sym.get_halo_fill());
            ren.set_halo_radius(sym.get_halo_radius());
        }

        // set font size
        unsigned size = sym.eval_size(feature);
        ren.set_pixel_size(size);
        faces->set_pixel_sizes(size);

        // Get and render text path
        //
        text_path_ptr path = sym.get_text_path(faces, feature);
        // apply displacement
        position pos = sym.get_displacement();
        double dx = boost::get<0>(pos);
        double dy = boost::get<1>(pos);
        path->starting_x = x = x+dx;
        path->starting_y = y = y+dy;

        // Prepare glyphs to set internal state and calculate the marker's
        // final box so we can check for a valid placement
        box2d<double> dim = ren.prepare_glyphs(path.get());
        double bsize = (dim.width()>dim.height()?dim.width():dim.height())/2;
        box2d<double> ext(
            floor(x-bsize), floor(y-bsize), ceil(x+bsize), ceil(y+bsize)
            );
        if ((sym.get_allow_overlap() || detector_.has_placement(ext)) &&
            (!sym.get_avoid_edges() || detector_.extent().contains(ext)))
        {    
           // Placement is valid, render glyph and update detector.
           ren.render(x, y);
           detector_.insert(ext);
        }
    }
    else
    {
        throw config_error(
            "Unable to find specified font face in GlyphSymbolizer"
            );
    }
}

template class agg_renderer<image_32>;
}