mapnik/src/cairo_renderer.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2008 Tom Hughes
 *
 * 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
 *
 *****************************************************************************/
//$Id$

#if defined(HAVE_CAIRO)

// mapnik
#include <mapnik/cairo_renderer.hpp>
#include <mapnik/image_util.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/path_expression_grammar.hpp>
#include <mapnik/image_cache.hpp>
// cairo
#include <cairomm/context.h>
#include <cairomm/surface.h>
#include <cairo-ft.h>

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

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

namespace mapnik
{
class cairo_pattern : private boost::noncopyable
{
public:
    cairo_pattern(image_data_32 const& data)
    {
	int pixels = data.width() * data.height();
	const unsigned int *in_ptr = data.getData();
	const unsigned int *in_end = in_ptr + pixels;
	unsigned int *out_ptr;

	out_ptr = data_ = new unsigned int[pixels];

	while (in_ptr < in_end)
	{
	    unsigned int in = *in_ptr++;
	    unsigned int r = (in >> 0) & 0xff;
	    unsigned int g = (in >> 8) & 0xff;
	    unsigned int b = (in >> 16) & 0xff;
	    unsigned int a = (in >> 24) & 0xff;

	    r = r * a / 255;
	    g = g * a / 255;
	    b = b * a / 255;

	    *out_ptr++ = (a << 24) | (r << 16) | (g << 8) | b;
	}

	surface_ = Cairo::ImageSurface::create(reinterpret_cast<unsigned char *>(data_), Cairo::FORMAT_ARGB32, data.width(), data.height(), data.width() * 4);
	pattern_ = Cairo::SurfacePattern::create(surface_);
    }

    ~cairo_pattern(void)
    {
	delete [] data_;
    }
         
    void set_matrix(Cairo::Matrix const& matrix)
    {
	pattern_->set_matrix(matrix);
    }

    void set_origin(double x, double y)
    {
	Cairo::Matrix matrix;
            
	pattern_->get_matrix(matrix);
     
	matrix.x0 = -x;
	matrix.y0 = -y;
            
	pattern_->set_matrix(matrix);
    }
         
    void set_extend(Cairo::Extend extend)
    {
	pattern_->set_extend(extend);
    }

    void set_filter(Cairo::Filter filter)
    {
	pattern_->set_filter(filter);
    }

    Cairo::RefPtr<Cairo::SurfacePattern> const& pattern(void) const
    {
	return pattern_;
    }

private:
    unsigned int *data_;
    Cairo::RefPtr<Cairo::ImageSurface> surface_;
    Cairo::RefPtr<Cairo::SurfacePattern> pattern_;
};

class cairo_face : private boost::noncopyable
{
public:
    cairo_face(boost::shared_ptr<freetype_engine> const& engine, face_ptr const& face)
	: face_(face)
    {
	static cairo_user_data_key_t key;
	cairo_font_face_t *c_face;

	c_face = cairo_ft_font_face_create_for_ft_face(face->get_face(), FT_LOAD_NO_HINTING);
	cairo_font_face_set_user_data(c_face, &key, new handle(engine, face), destroy);

	cairo_face_ = Cairo::RefPtr<Cairo::FontFace>(new Cairo::FontFace(c_face));
    }

    Cairo::RefPtr<Cairo::FontFace> const& face(void) const
    {
	return cairo_face_;
    }

private:
    class handle
    {
    public:
	handle(boost::shared_ptr<freetype_engine> const& engine, face_ptr const& face)
	    : engine_(engine), face_(face) {}

    private:
	boost::shared_ptr<freetype_engine> engine_;
	face_ptr face_;
    };

    static void destroy(void *data)
    {
	handle *h = static_cast<handle *>(data);

	delete h;
    }

private:
    face_ptr face_;
    Cairo::RefPtr<Cairo::FontFace> cairo_face_;
};

cairo_face_manager::cairo_face_manager(boost::shared_ptr<freetype_engine> engine,
				       face_manager<freetype_engine> & manager)
    : font_engine_(engine),
      font_manager_(manager)
{
}

cairo_face_ptr cairo_face_manager::get_face(face_ptr face)
{
    cairo_face_cache::iterator itr = cache_.find(face);
    cairo_face_ptr entry;

    if (itr != cache_.end())
    {
	entry = itr->second;
    }
    else
    {
	entry = cairo_face_ptr(new cairo_face(font_engine_, face));

	cache_.insert(std::make_pair(face, entry));
    }

    return entry;
}

class cairo_context : private boost::noncopyable
{
public:
    cairo_context(Cairo::RefPtr<Cairo::Context> const& context)
	: context_(context)
    {
	context_->save();
    }

    ~cairo_context(void)
    {
	context_->restore();
    }

    void set_color(color const &color, double opacity = 1.0)
    {
	set_color(color.red(), color.green(), color.blue(), color.alpha() * opacity / 255.0);
    }

    void set_color(int r, int g, int b, double opacity = 1.0)
    {
	context_->set_source_rgba(r / 255.0, g / 255.0, b / 255.0, opacity);
    }

    void set_line_join(line_join_e join)
    {
	if (join == MITER_JOIN)
	    context_->set_line_join(Cairo::LINE_JOIN_MITER);
	else if (join == MITER_REVERT_JOIN)
	    context_->set_line_join(Cairo::LINE_JOIN_MITER);
	else if (join == ROUND_JOIN)
	    context_->set_line_join(Cairo::LINE_JOIN_ROUND);
	else
	    context_->set_line_join(Cairo::LINE_JOIN_BEVEL);
    }

    void set_line_cap(line_cap_e cap)
    {
	if (cap == BUTT_CAP)
	    context_->set_line_cap(Cairo::LINE_CAP_BUTT);
	else if (cap == SQUARE_CAP)
	    context_->set_line_cap(Cairo::LINE_CAP_SQUARE);
	else
	    context_->set_line_cap(Cairo::LINE_CAP_ROUND);
    }

    void set_miter_limit(double limit)
    {
	context_->set_miter_limit(limit);
    }

    void set_line_width(double width)
    {
	context_->set_line_width(width);
    }

    void set_dash(dash_array const &dashes)
    {
	std::valarray<double> d(dashes.size() * 2);
	dash_array::const_iterator itr = dashes.begin();
	dash_array::const_iterator end = dashes.end();
	int index = 0;

	for (; itr != end; ++itr)
	{
	    d[index++] = itr->first;
	    d[index++] = itr->second;
	}

	context_->set_dash(d, 0.0);
    }

    void move_to(double x, double y)
    {
#if CAIRO_VERSION < CAIRO_VERSION_ENCODE(1, 6, 0)
	if (x < -32767.0) x = -32767.0;
	else if (x > 32767.0) x = 32767.0;
	if (y < -32767.0) y = -32767.0;
	else if (y > 32767.0) y = 32767.0;
#endif

	context_->move_to(x, y);
    }


    void line_to(double x, double y)
    {
#if CAIRO_VERSION < CAIRO_VERSION_ENCODE(1, 6, 0)
	if (x < -32767.0) x = -32767.0;
	else if (x > 32767.0) x = 32767.0;
	if (y < -32767.0) y = -32767.0;
	else if (y > 32767.0) y = 32767.0;
#endif

	context_->line_to(x, y);
    }

    template <typename T>
    void add_path(T path)
    {
	double x, y;

	path.rewind(0);

	for (unsigned cm = path.vertex(&x, &y); cm != SEG_END; cm = path.vertex(&x, &y))
	{
	    if (cm == SEG_MOVETO)
	    {
		move_to(x, y);
	    }
	    else if (cm == SEG_LINETO)
	    {
		line_to(x, y);
	    }
	}
    }

    void rectangle(double x, double y, double w, double h)
    {
	context_->rectangle(x, y, w, h);
    }

    void stroke(void)
    {
	context_->stroke();
    }

    void fill(void)
    {
	context_->fill();
    }

    void paint(void)
    {
	context_->paint();
    }

    void set_pattern(cairo_pattern const& pattern)
    {
	context_->set_source(pattern.pattern());
    }

    void add_image(double x, double y, image_data_32 & data, double opacity = 1.0)
    {
	cairo_pattern pattern(data);

	pattern.set_origin(x, y);

	context_->save();
	context_->set_source(pattern.pattern());
	context_->paint_with_alpha(opacity);
	context_->restore();
    }

    void set_font_face(cairo_face_manager & manager, face_ptr face)
    {
	context_->set_font_face(manager.get_face(face)->face());
    }

    void set_font_matrix(Cairo::Matrix const& matrix)
    {
	context_->set_font_matrix(matrix);
    }

    void show_glyph(unsigned long index, double x, double y)
    {
	Cairo::Glyph glyph;

	glyph.index = index;
	glyph.x = x;
	glyph.y = y;

	std::vector<Cairo::Glyph> glyphs;

	glyphs.push_back(glyph);

	context_->show_glyphs(glyphs);
    }

    void glyph_path(unsigned long index, double x, double y)
    {
	Cairo::Glyph glyph;

	glyph.index = index;
	glyph.x = x;
	glyph.y = y;

	std::vector<Cairo::Glyph> glyphs;

	glyphs.push_back(glyph);

	context_->glyph_path(glyphs);
    }

    void add_text(text_symbolizer const& sym, text_path & path,
		  cairo_face_manager & manager,
		  face_set_ptr const& faces)
    {
	unsigned text_size = sym.get_text_size();
	double sx = path.starting_x;
	double sy = path.starting_y;

	path.rewind();

	for (int iii = 0; iii < path.num_nodes(); iii++)
	{
	    int c;
	    double x, y, angle;

	    path.vertex(&c, &x, &y, &angle);

	    glyph_ptr glyph = faces->get_glyph(c);
 
	    if (glyph)
	    {
		Cairo::Matrix matrix;

		matrix.xx = text_size * cos(angle);
		matrix.xy = text_size * sin(angle);
		matrix.yx = text_size * -sin(angle);
		matrix.yy = text_size * cos(angle);
		matrix.x0 = 0;
		matrix.y0 = 0;

		set_font_matrix(matrix);

		set_font_face(manager, glyph->get_face());

		glyph_path(glyph->get_index(), sx + x, sy - y);
	    }
	}

	set_line_width(sym.get_halo_radius());
	set_line_join(ROUND_JOIN);
	set_color(sym.get_halo_fill());
	stroke();

	set_color(sym.get_fill());

	path.rewind();

	for (int iii = 0; iii < path.num_nodes(); iii++)
	{
	    int c;
	    double x, y, angle;

	    path.vertex(&c, &x, &y, &angle);

	    glyph_ptr glyph = faces->get_glyph(c);
 
	    if (glyph)
	    {
		Cairo::Matrix matrix;

		matrix.xx = text_size * cos(angle);
		matrix.xy = text_size * sin(angle);
		matrix.yx = text_size * -sin(angle);
		matrix.yy = text_size * cos(angle);
		matrix.x0 = 0;
		matrix.y0 = 0;

		set_font_matrix(matrix);

		set_font_face(manager, glyph->get_face());

		show_glyph(glyph->get_index(), sx + x, sy - y);
	    }
	}
    }


private:
    Cairo::RefPtr<Cairo::Context> context_;
};

cairo_renderer_base::cairo_renderer_base(Map const& m, Cairo::RefPtr<Cairo::Context> const& context, unsigned offset_x, unsigned offset_y)
    : m_(m),
      context_(context),
      t_(m.getWidth(),m.getHeight(),m.getCurrentExtent(),offset_x,offset_y),
      font_engine_(new freetype_engine()),
      font_manager_(*font_engine_),
      face_manager_(font_engine_,font_manager_),
      detector_(box2d<double>(-m.buffer_size() ,-m.buffer_size() , m.getWidth() + m.buffer_size() ,m.getHeight() + m.buffer_size()))
{
#ifdef MAPNIK_DEBUG
    std::clog << "scale=" << m.scale() << "\n";
#endif
}

template <>
cairo_renderer<Cairo::Context>::cairo_renderer(Map const& m, Cairo::RefPtr<Cairo::Context> const& context, unsigned offset_x, unsigned offset_y)
    : feature_style_processor<cairo_renderer>(m),
      cairo_renderer_base(m,context,offset_x,offset_y)
{
}

template <>
cairo_renderer<Cairo::Surface>::cairo_renderer(Map const& m, Cairo::RefPtr<Cairo::Surface> const& surface, unsigned offset_x, unsigned offset_y)
    : feature_style_processor<cairo_renderer>(m),
      cairo_renderer_base(m,Cairo::Context::create(surface),offset_x,offset_y)
{
}

cairo_renderer_base::~cairo_renderer_base() {}

void cairo_renderer_base::start_map_processing(Map const& map)
{
#ifdef MAPNIK_DEBUG
    std::clog << "start map processing bbox="
	      << map.getCurrentExtent() << "\n";
#endif

#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 6, 0)
    box2d<double> bounds = t_.forward(t_.extent());
    context_->rectangle(bounds.minx(), bounds.miny(), bounds.maxx(), bounds.maxy());
    context_->clip();
#endif

    boost::optional<color> bg = m_.background();
    if (bg)
    {
	cairo_context context(context_);
	context.set_color(*bg);
	context.paint();
    }
}

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

template <>
void cairo_renderer<Cairo::Surface>::end_map_processing(Map const& )
{
#ifdef MAPNIK_DEBUG
    std::clog << "end map processing\n";
#endif
    context_->show_page();
}

void cairo_renderer_base::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();
    }
}

void cairo_renderer_base::end_layer_processing(layer const&)
{
#ifdef MAPNIK_DEBUG
    std::clog << "end layer processing\n";
#endif
}

void cairo_renderer_base::process(polygon_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
    typedef coord_transform2<CoordTransform,geometry2d> path_type;

    cairo_context context(context_);

    context.set_color(sym.get_fill(), sym.get_opacity());

    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);

            context.add_path(path);
            context.fill();
	}
    }
}

typedef boost::tuple<double,double,double,double> segment_t;
bool cairo_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;
}

void cairo_renderer_base::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;

    cairo_context context(context_);

    color const& fill = sym.get_fill();
    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);
		}

		if (j != 0)
		{
		    face_segments.push_back(segment_t(x0, y0, x, y));
		}

		x0 = x;
		y0 = y;
            }

            std::sort(face_segments.begin(), face_segments.end(), cairo_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);
		context.set_color(int(fill.red() * 0.8), int(fill.green() * 0.8),
				  int(fill.blue() * 0.8), fill.alpha() * sym.get_opacity() / 255.0);
		context.add_path(faces_path);
		context.fill();

		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);
            context.set_color(128, 128, 128, sym.get_opacity());
            context.add_path(path);
            context.stroke();

            path_type roof_path(t_, *roof, prj_trans);
            context.set_color(sym.get_fill(), sym.get_opacity());
            context.add_path(roof_path);
            context.fill();
	}
    }
}

void cairo_renderer_base::process(line_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
    typedef coord_transform2<CoordTransform,geometry2d> path_type;

    cairo_context context(context_);
    mapnik::stroke const& stroke_ = sym.get_stroke();

    context.set_color(stroke_.get_color(), stroke_.get_opacity());

    for (unsigned i = 0; i < feature.num_geometries(); ++i)
    {
	geometry2d const& geom = feature.get_geometry(i);

	if (geom.num_points() > 1)
	{
            cairo_context context(context_);
            path_type path(t_, geom, prj_trans);

            if (stroke_.has_dash())
            {
		context.set_dash(stroke_.get_dash_array());
            }

            context.set_line_join(stroke_.get_line_join());
            context.set_line_cap(stroke_.get_line_cap());
            context.set_miter_limit(4.0);
            context.set_line_width(stroke_.get_width());
            context.add_path(path);
            context.stroke();
	}
    }
}

void cairo_renderer_base::process(point_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{   
    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> data;
    
    if ( filename.empty() )
    {
        // default OGC 4x4 black pixel
        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);
	    double x;
	    double y;
	    double z = 0;
	       
	    geom.label_position(&x, &y);
	    prj_trans.backward(x, y, z);
	    t_.forward(&x, &y);
	       
	    int w = (*data)->width();
	    int h = (*data)->height();
	       
	    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))
            {
		cairo_context context(context_);
		int px = int(floor(x - 0.5 * w));
		int py = int(floor(y - 0.5 * h));

		context.add_image(px, py, *(*data), sym.get_opacity());
		detector_.insert(label_ext);
            }
	}
    }
}

void cairo_renderer_base::process(shield_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();
    
    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)
	{
            cairo_context context(context_);
            string_info info(text);

            faces->set_pixel_sizes(sym.get_text_size());
            faces->get_string_info(info);

            placement_finder<label_collision_detector4> finder(detector_);

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

            for (unsigned i = 0; i < feature.num_geometries(); ++i)
            {
		geometry2d const& geom = feature.get_geometry(i);

		if (geom.num_points() > 0) // don't bother with empty geometries
		{
		    path_type path(t_, geom, prj_trans);

		    if (sym.get_label_placement() == POINT_PLACEMENT) 
		    {
			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();
			geom.label_position(&label_x, &label_y);
			prj_trans.backward(label_x, label_y, z);
			t_.forward(&label_x, &label_y);
			finder.find_point_placement(text_placement, label_x, label_y);

			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;
			    // remove displacement from image label
			    position pos = sym.get_displacement();
			    double lx = x - boost::get<0>(pos);
			    double ly = y - boost::get<1>(pos);
			    int px = int(lx - (0.5 * w)) ;
			    int py = int(ly - (0.5 * h)) ;
			    box2d<double> label_ext (floor(lx - 0.5 * w), floor(ly - 0.5 * h), ceil (lx + 0.5 * w), ceil (ly + 0.5 * h));

			    if (detector_.has_placement(label_ext))
			    {    
				context.add_image(px, py, *(*data));
				context.add_text(sym, text_placement.placements[ii], face_manager_, faces);

				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)
			{
			    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));

			    context.add_image(px, py, *(*data));
			    context.add_text(sym, text_placement.placements[ii], face_manager_, faces);
			}

			finder.update_detector(text_placement);
		    }
		}
            }
	}
    }
}

void cairo_renderer_base::process(line_pattern_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
    typedef coord_transform2<CoordTransform,geometry2d> path_type;
    
    std::string filename = path_processor_type::evaluate( *sym.get_filename(), feature);
    boost::optional<mapnik::image_ptr> image = mapnik::image_cache::instance()->find(filename,true);
    if (!image) return;
    
    unsigned width((*image)->width());
    unsigned height((*image)->height());

    cairo_context context(context_);
    cairo_pattern pattern(*(*image));

    pattern.set_extend(Cairo::EXTEND_REPEAT);
    pattern.set_filter(Cairo::FILTER_BILINEAR);
    context.set_line_width(height);

    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);
            double length(0);
            double x0(0), y0(0);
            double x, y;

            for (unsigned cm = path.vertex(&x, &y); cm != SEG_END; cm = path.vertex(&x, &y))
            {
		if (cm == SEG_MOVETO)
		{
		    length = 0.0;
		}
		else if (cm == SEG_LINETO)
		{
		    double dx = x - x0;
		    double dy = y - y0;
		    double angle = atan2(dy, dx);
		    double offset = fmod(length, width);
                  
		    Cairo::Matrix matrix;
		    cairo_matrix_init_identity(&matrix);
		    cairo_matrix_translate(&matrix,x0,y0);
		    cairo_matrix_rotate(&matrix,angle);
		    cairo_matrix_translate(&matrix,-offset,0.5*height);
		    cairo_matrix_invert(&matrix);

		    pattern.set_matrix(matrix);
     
		    context.set_pattern(pattern);
                  
		    context.move_to(x0, y0);
		    context.line_to(x, y);
		    context.stroke();

		    length = length + hypot(x - x0, y - y0);
		}

		x0 = x;
		y0 = y;
            }
	}
    }
}

void cairo_renderer_base::process(polygon_pattern_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
    typedef coord_transform2<CoordTransform,geometry2d> path_type;

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

    if (!image) return;

    cairo_pattern pattern(*(*image));

    pattern.set_extend(Cairo::EXTEND_REPEAT);

    context.set_pattern(pattern);

    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);

            context.add_path(path);
            context.fill();
	}
    }
}

void cairo_renderer_base::process(raster_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
    // TODO -- at the moment raster_symbolizer is an empty class
    // used for type dispatching, but we can have some fancy raster
    // processing in a future (filters??). Just copy raster into pixmap for now.
    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 = int(round(ext.minx()));
        int start_y = int(round(ext.miny()));
        int raster_width = int(round(ext.width()));
        int raster_height = int(round(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);
            //TODO -- use cairo matrix transformation for scaling
            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_);
            }
            cairo_context context(context_);
            //TODO -- support for advanced image merging
            context.add_image(start_x, start_y, target, sym.get_opacity());
        }
    }
}

void cairo_renderer_base::process(markers_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
}

void cairo_renderer_base::process(glyph_symbolizer const& sym,
				  Feature const& feature,
				  proj_transform const& prj_trans)
{
}

void cairo_renderer_base::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)
    {
	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)
	{
            cairo_context context(context_);
            string_info info(text);

            faces->set_pixel_sizes(sym.get_text_size());
            faces->get_string_info(info);

            placement_finder<label_collision_detector4> finder(detector_);

            for (unsigned i = 0; i < feature.num_geometries(); ++i)
            {
		geometry2d const& geom = feature.get_geometry(i);

		if (geom.num_points() > 0) // don't bother with empty geometries
		{
		    path_type path(t_, geom, prj_trans);
		    placement text_placement(info, sym);

		    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);
			finder.find_point_placement(text_placement, label_x, label_y);
			finder.update_detector(text_placement);
		    }
		    else //LINE_PLACEMENT
		    {
			finder.find_line_placements<path_type>(text_placement, path);
		    }

		    for (unsigned int ii = 0; ii < text_placement.placements.size(); ++ii)
		    {
			context.add_text(sym, text_placement.placements[ii], face_manager_, faces);
		    }
		}
            }
	}
	else
	{
            throw config_error("Unable to find specified font face '" + sym.get_face_name() + "'");
	}
    }
}

template class cairo_renderer<Cairo::Surface>;
template class cairo_renderer<Cairo::Context>;
}

#endif