mapnik/src/cairo_renderer.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2011 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
 *
 *****************************************************************************/
//$Id$

#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_placement.hpp>
#include <mapnik/arrow.hpp>
#include <mapnik/config_error.hpp>
#include <mapnik/parse_path.hpp>
#include <mapnik/marker_cache.hpp>
#include <mapnik/svg/svg_path_adapter.hpp>
#include <mapnik/svg/svg_path_attributes.hpp>
#include <mapnik/segment.hpp>
#include <mapnik/symbolizer_helpers.hpp>
#include <mapnik/expression_evaluator.hpp>
#include <mapnik/warp.hpp>
#include <mapnik/config.hpp>

// cairo
#include <cairomm/context.h>
#include <cairomm/surface.h>
#include <cairo-ft.h>

// boost
#include <boost/utility.hpp>
#include <boost/make_shared.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;

        surface_ = Cairo::ImageSurface::create(Cairo::FORMAT_ARGB32, data.width(), data.height());

        out_ptr = reinterpret_cast<unsigned int *>(surface_->get_data());

        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;
        }
        // mark the surface as dirty as we've modified it behind cairo's back
        surface_->mark_dirty();
        pattern_ = Cairo::SurfacePattern::create(surface_);
    }

    ~cairo_pattern(void)
    {
    }

    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:
    Cairo::RefPtr<Cairo::ImageSurface> surface_;
    Cairo::RefPtr<Cairo::SurfacePattern> pattern_;
};

class cairo_gradient : private boost::noncopyable
{
public:
    cairo_gradient(const mapnik::gradient &grad, double opacity=1.0)
    {
        double x1,x2,y1,y2,r;
        grad.get_control_points(x1,y1,x2,y2,r);
        if (grad.get_gradient_type() == LINEAR)
        {
            pattern_ = Cairo::LinearGradient::create(x1, y1, x2, y2);
        }
        else if (grad.get_gradient_type() == RADIAL)
        {
            pattern_ = Cairo::RadialGradient::create(x1, y1, 0, x2, y2, r);
        }

        units_ = grad.get_units();

        BOOST_FOREACH ( mapnik::stop_pair const& st, grad.get_stop_array() )
        {
            mapnik::color const& stop_color = st.second;
            double r= static_cast<double> (stop_color.red())/255.0;
            double g= static_cast<double> (stop_color.green())/255.0;
            double b= static_cast<double> (stop_color.blue())/255.0;
            double a= static_cast<double> (stop_color.alpha())/255.0;
            pattern_->add_color_stop_rgba(st.first, r, g, b, a*opacity);
        }

        double m[6];
        agg::trans_affine tr = grad.get_transform();
        tr.invert();
        tr.store_to(m);
        pattern_->set_matrix(Cairo::Matrix(m[0],m[1],m[2],m[3],m[4],m[5]));
    }

    ~cairo_gradient(void)
    {
    }


    Cairo::RefPtr<Cairo::Gradient> const& gradient(void) const
    {
        return pattern_;
    }

    gradient_unit_e units() const
    {
        return units_;
    }

private:
    Cairo::RefPtr<Cairo::Gradient> pattern_;
    gradient_unit_e units_;

};

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 set_fill_rule(Cairo::FillRule fill_rule)
    {
        context_->set_fill_rule(fill_rule);
    }

    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 curve_to(double ct1_x, double ct1_y, double ct2_x, double ct2_y, double end_x, double end_y)
    {
        context_->curve_to(ct1_x,ct1_y,ct2_x,ct2_y,end_x,end_y);
    }

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

    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, unsigned start_index = 0)
    {
        double x, y;

        path.rewind(start_index);

        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);
            }
        }
    }

    template <typename T>
    void add_agg_path(T& path, unsigned start_index = 0)
    {
        double x=0;
        double y=0;

        path.rewind(start_index);

        for (unsigned cm = path.vertex(&x, &y); !agg::is_stop(cm); cm = path.vertex(&x, &y))
        {
            if (agg::is_move_to(cm))
            {
                move_to(x, y);
            }
            else if (agg::is_drawing(cm))
            {
                if (agg::is_curve3(cm))
                {
                    double end_x=0;
                    double end_y=0;
                    std::cerr << "Curve 3 not implemented" << std::endl;
                    path.vertex(&end_x, &end_y);

                    curve_to(x,y,x,y,end_x,end_y);
                }
                else if (agg::is_curve4(cm))
                {
                    double ct2_x=0;
                    double ct2_y=0;
                    double end_x=0;
                    double end_y=0;

                    path.vertex(&ct2_x, &ct2_y);
                    path.vertex(&end_x, &end_y);

                    curve_to(x,y,ct2_x,ct2_y,end_x,end_y);
                }
                else if (agg::is_line_to(cm))
                {
                    line_to(x, y);
                }
                else
                {
                    std::cerr << "Unimplemented drawing command: " << cm << std::endl;
                    move_to(x, y);
                }
            }
            else if (agg::is_close(cm))
            {
                close_path();
            }
            else
            {
                std::cerr << "Unimplemented path command: " << cm << std::endl;
            }
        }
    }

    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 set_gradient(cairo_gradient const& pattern, const box2d<double> &bbox)
    {
        Cairo::RefPtr<Cairo::Gradient> p = pattern.gradient();

        double bx1=bbox.minx();
        double by1=bbox.miny();
        double bx2=bbox.maxx();
        double by2=bbox.maxy();
        if (pattern.units() != USER_SPACE_ON_USE)
        {
            if (pattern.units() == OBJECT_BOUNDING_BOX)
            {
                context_->get_path_extents (bx1, by1, bx2, by2);
            }
            Cairo::Matrix m = p->get_matrix();
            m.scale(1.0/(bx2-bx1),1.0/(by2-by1));
            m.translate(-bx1,-by1);
            p->set_matrix(m);
        }

        context_->set_source(p);
    }

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

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

    void translate(double x, double y)
    {
        context_->translate(x,y);
    }

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

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

    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_path & path,
                  cairo_face_manager & manager,
                  face_manager<freetype_engine> &font_manager)
    {
        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;
            char_properties *format;

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

            face_set_ptr faces = font_manager.get_face_set(format->face_name, format->fontset);
            float text_size = format->text_size;
            faces->set_character_sizes(text_size);

            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(format->halo_radius);
                set_line_join(ROUND_JOIN);
                set_color(format->halo_fill);
                stroke();
                set_color(format->fill);
                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.width(),m.height(),m.get_current_extent(),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.width() + m.buffer_size() ,m.height() + 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() {}

#ifdef MAPNIK_DEBUG
void cairo_renderer_base::start_map_processing(Map const& map)
{
    std::clog << "start map processing bbox="
              << map.get_current_extent() << "\n";
#else
    void cairo_renderer_base::start_map_processing(Map const& /*map*/)
    {
#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,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> path_type;

        cairo_context context(context_);

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

        for (unsigned i = 0; i < feature->num_geometries(); ++i)
        {
            geometry_type 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(building_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> path_type;

        cairo_context context(context_);

        color const& fill = sym.get_fill();
        double height = 0.0;
        expression_ptr height_expr = sym.height();
        if (height_expr)
        {
            value_type result = boost::apply_visitor(evaluate<Feature,value_type>(*feature), *height_expr);
            height = 0.7071 * result.to_double();
        }

        for (unsigned i = 0; i < feature->num_geometries(); ++i)
        {
            geometry_type const& geom = feature->get_geometry(i);

            if (geom.num_points() > 2)
            {
                boost::scoped_ptr<geometry_type> frame(new geometry_type(LineString));
                boost::scoped_ptr<geometry_type> roof(new geometry_type(Polygon));
                std::deque<segment_t> face_segments;
                double x0(0);
                double y0(0);

                geom.rewind(0);
                unsigned cm = geom.vertex(&x0, &y0);

                for (unsigned j = 1; j < geom.num_points(); ++j)
                {
                    double x=0;
                    double y=0;

                    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(), y_order);
                std::deque<segment_t>::const_iterator itr = face_segments.begin();
                for (; itr != face_segments.end(); ++itr)
                {
                    boost::scoped_ptr<geometry_type> faces(new geometry_type(Polygon));

                    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,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> 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)
        {
            geometry_type 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::render_marker(const int x, const int y, marker &marker, const agg::trans_affine & tr, double opacity)

    {
        cairo_context context(context_);
        if (marker.is_vector())
        {
            box2d<double> bbox;
            bbox = (*marker.get_vector_data())->bounding_box();

            coord<double,2> c = bbox.center();
            // center the svg marker on '0,0'
            agg::trans_affine mtx = agg::trans_affine_translation(-c.x,-c.y);
            // apply symbol transformation to get to map space
            mtx *= tr;
            // render the marker at the center of the marker box
            mtx.translate(x+0.5 * marker.width(), y+0.5 * marker.height());

            typedef coord_transform2<CoordTransform,geometry_type> path_type;
            mapnik::path_ptr vmarker = *marker.get_vector_data();

            agg::pod_bvector<path_attributes> const & attributes_ = vmarker->attributes();
            for(unsigned i = 0; i < attributes_.size(); ++i)
            {
                mapnik::svg::path_attributes const& attr = attributes_[i];
                if (!attr.visibility_flag)
                    continue;

                context.save();

                agg::trans_affine transform = attr.transform;
                transform *= mtx;

                if (transform.is_valid() && !transform.is_identity())
                {
                    double m[6];
                    transform.store_to(m);
                    context.transform(Cairo::Matrix(m[0],m[1],m[2],m[3],m[4],m[5]));
                }

                vertex_stl_adapter<svg_path_storage> stl_storage(vmarker->source());
                svg_path_adapter svg_path(stl_storage);

                if (attr.fill_flag || attr.fill_gradient.get_gradient_type() != NO_GRADIENT)
                {
                    context.add_agg_path(svg_path,attr.index);
                    if (attr.even_odd_flag)
                    {
                        context.set_fill_rule(Cairo::FILL_RULE_EVEN_ODD);
                    }
                    else
                    {
                        context.set_fill_rule(Cairo::FILL_RULE_WINDING);
                    }
                    if(attr.fill_gradient.get_gradient_type() != NO_GRADIENT)
                    {
                        cairo_gradient g(attr.fill_gradient,attr.opacity*opacity);

                        context.set_gradient(g,bbox);
                        context.fill();
                    }
                    else if(attr.fill_flag)
                    {
                        context.set_color(attr.fill_color.r,attr.fill_color.g,attr.fill_color.b,attr.opacity*opacity);
                        context.fill();
                    }
                }


                if(attr.stroke_gradient.get_gradient_type() != NO_GRADIENT || attr.stroke_flag)
                {
                    context.add_agg_path(svg_path,attr.index);
                    if(attr.stroke_gradient.get_gradient_type() != NO_GRADIENT)
                    {
                        context.set_line_width(attr.stroke_width);
                        context.set_line_cap(line_cap_enum(attr.line_cap));
                        context.set_line_join(line_join_enum(attr.line_join));
                        context.set_miter_limit(attr.miter_limit);
                        cairo_gradient g(attr.stroke_gradient,attr.opacity*opacity);
                        context.set_gradient(g,bbox);
                        context.stroke();
                    }
                    else if(attr.stroke_flag)
                    {
                        context.set_color(attr.stroke_color.r,attr.stroke_color.g,attr.stroke_color.b,attr.opacity*opacity);
                        context.set_line_width(attr.stroke_width);
                        context.set_line_cap(line_cap_enum(attr.line_cap));
                        context.set_line_join(line_join_enum(attr.line_join));
                        context.set_miter_limit(attr.miter_limit);
                        context.stroke();
                    }
                }

                context.restore();
            }
        }
        else if (marker.is_bitmap())
        {
            context.add_image(x, y, **marker.get_bitmap_data(), opacity);
        }
    }

    void cairo_renderer_base::process(point_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        std::string filename = path_processor_type::evaluate( *sym.get_filename(), *feature);

        boost::optional<marker_ptr> marker;
        if ( !filename.empty() )
        {
            marker = marker_cache::instance()->find(filename, true);
        }
        else
        {
            marker.reset(boost::make_shared<mapnik::marker>());
        }

        if (marker)
        {
            for (unsigned i = 0; i < feature->num_geometries(); ++i)
            {
                geometry_type const& geom = feature->get_geometry(i);
                double x;
                double y;
                double z = 0;

                if (sym.get_point_placement() == CENTROID_POINT_PLACEMENT)
                    geom.label_position(&x, &y);
                else
                    geom.label_interior_position(&x, &y);

                prj_trans.backward(x, y, z);
                t_.forward(&x, &y);

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

                int px = int(floor(x - 0.5 * w));
                int py = int(floor(y - 0.5 * h));
                box2d<double> label_ext (px, py, px + w, py + h);
                if (sym.get_allow_overlap() ||
                    detector_.has_placement(label_ext))
                {
                    agg::trans_affine mtx;
                    boost::array<double,6> const& m = sym.get_transform();
                    mtx.load_from(&m[0]);

                    render_marker(px,py,**marker, mtx, sym.get_opacity());

                    if (!sym.get_ignore_placement())
                        detector_.insert(label_ext);
                    metawriter_with_properties writer = sym.get_metawriter();
                    if (writer.first)
                    {
                        writer.first->add_box(label_ext, *feature, t_, writer.second);
                    }
                }
            }
        }
    }

    void cairo_renderer_base::process(shield_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        shield_symbolizer_helper<face_manager<freetype_engine>,
            label_collision_detector4> helper(
                sym, *feature, prj_trans,
                detector_.extent().width(), detector_.extent().height(),
                1.0 /*scale_factor*/,
                t_, font_manager_, detector_);

        cairo_context context(context_);

        text_placement_info_ptr placement;
        while ((placement = helper.get_placement())) {
            for (unsigned int ii = 0; ii < placement->placements.size(); ++ii)
            {
                std::pair<int, int> marker_pos = helper.get_marker_position(placement->placements[ii]);
                render_marker(marker_pos.first, marker_pos.second,
                              helper.get_marker(), helper.get_transform(),
                              sym.get_opacity());
                context.add_text(placement->placements[ii], face_manager_, font_manager_);
            }
        }
    }

    void cairo_renderer_base::process(line_pattern_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> path_type;

        std::string filename = path_processor_type::evaluate( *sym.get_filename(), *feature);
        boost::optional<mapnik::marker_ptr> marker = mapnik::marker_cache::instance()->find(filename,true);
        if (!marker && !(*marker)->is_bitmap()) return;

        unsigned width((*marker)->width());
        unsigned height((*marker)->height());

        cairo_context context(context_);
        cairo_pattern pattern(**((*marker)->get_bitmap_data()));

        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)
        {
            geometry_type 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,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> path_type;

        cairo_context context(context_);
        std::string filename = path_processor_type::evaluate( *sym.get_filename(), *feature);
        boost::optional<mapnik::marker_ptr> marker = mapnik::marker_cache::instance()->find(filename,true);
        if (!marker && !(*marker)->is_bitmap()) return;

        cairo_pattern pattern(**((*marker)->get_bitmap_data()));

        pattern.set_extend(Cairo::EXTEND_REPEAT);

        context.set_pattern(pattern);

        for (unsigned i = 0; i < feature->num_geometries(); ++i)
        {
            geometry_type 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,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        raster_ptr const& source = feature->get_raster();
        if (source)
        {
            // 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(source,*feature);

            box2d<double> target_ext = box2d<double>(source->ext_);
            prj_trans.backward(target_ext, PROJ_ENVELOPE_POINTS);

            box2d<double> ext=t_.forward(target_ext);
            int start_x = (int)ext.minx();
            int start_y = (int)ext.miny();
            int end_x = (int)ceil(ext.maxx());
            int end_y = (int)ceil(ext.maxy());
            int raster_width = end_x - start_x;
            int raster_height = end_y - start_y;
            double err_offs_x = ext.minx() - start_x;
            double err_offs_y = ext.miny() - start_y;

            if (raster_width > 0 && raster_height > 0)
            {
                double scale_factor = ext.width() / source->data_.width();
                image_data_32 target_data(raster_width,raster_height);
                raster target(target_ext, target_data);

                reproject_raster(target, *source, prj_trans, err_offs_x, err_offs_y,
                                 sym.get_mesh_size(),
                                 sym.calculate_filter_factor(),
                                 scale_factor,
                                 sym.get_scaling());

                cairo_context context(context_);
                //TODO -- support for advanced image merging
                context.add_image(start_x, start_y, target.data_, sym.get_opacity());
            }
        }
    }

// TODO - this is woefully behind the AGG version.
    void cairo_renderer_base::process(markers_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform2<CoordTransform,geometry_type> path_type;
        arrow arrow_;
        cairo_context context(context_);

        color const& fill_ = sym.get_fill();
        context.set_color(fill_.red(), fill_.green(), fill_.blue(), fill_.alpha());

        for (unsigned i = 0; i < feature->num_geometries(); ++i)
        {
            geometry_type const& geom = feature->get_geometry(i);

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

                markers_placement<path_type, label_collision_detector4> placement(path, arrow_.extent(), detector_, sym.get_spacing(), sym.get_max_error(), sym.get_allow_overlap());

                double x, y, angle;
                while (placement.get_point(&x, &y, &angle)) {
                    Cairo::Matrix matrix = Cairo::rotation_matrix(angle) * Cairo::translation_matrix(x,y) ;
                    context.set_matrix(matrix);
                    context.add_path(arrow_);
                }
            }
            context.fill();
        }
    }

    void cairo_renderer_base::process(text_symbolizer const& sym,
                                      mapnik::feature_ptr const& feature,
                                      proj_transform const& prj_trans)
    {
        text_symbolizer_helper<face_manager<freetype_engine>, label_collision_detector4> helper(sym, *feature, prj_trans, detector_.extent().width(), detector_.extent().height(), 1.0 /*scale_factor*/, t_, font_manager_, detector_);

        cairo_context context(context_);
        text_placement_info_ptr placement;
        while ((placement = helper.get_placement())) {
            for (unsigned int ii = 0; ii < placement->placements.size(); ++ii)
            {
                context.add_text(placement->placements[ii], face_manager_, font_manager_);
            }
        }
    }

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

#endif