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
 *
 *****************************************************************************/

#if defined(HAVE_CAIRO)

// mapnik
#include <mapnik/debug.hpp>
#include <mapnik/cairo_renderer.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/markers_placement.hpp>
#include <mapnik/arrow.hpp>
#include <mapnik/parse_path.hpp>
#include <mapnik/marker.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>
#include <mapnik/text_path.hpp>
#include <mapnik/vertex_converters.hpp>

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

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

// agg

#include "agg_conv_clip_polyline.h"
#include "agg_conv_clip_polygon.h"
#include "agg_conv_smooth_poly1.h"

// markers
#include "agg_path_storage.h"
#include "agg_ellipse.h"

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 = boost::make_shared<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_operator(composite_mode_e comp_op)
    {
        switch (comp_op)
        {
        case clear:
            context_->set_operator(Cairo::OPERATOR_CLEAR);
            break;
        case src:
            context_->set_operator(Cairo::OPERATOR_SOURCE);
            break;
        case dst:
            context_->set_operator(Cairo::OPERATOR_DEST);
            break;
        case src_over:
            context_->set_operator(Cairo::OPERATOR_OVER);
            break;
        case dst_over:
            context_->set_operator(Cairo::OPERATOR_DEST_OVER);
            break;
        case src_in:
            context_->set_operator(Cairo::OPERATOR_IN);
            break;
        case dst_in:
            context_->set_operator(Cairo::OPERATOR_DEST_IN);
            break;
        case src_out:
            context_->set_operator(Cairo::OPERATOR_OUT);
            break;
        case dst_out:
            context_->set_operator(Cairo::OPERATOR_DEST_OUT);
            break;
        case src_atop:
            context_->set_operator(Cairo::OPERATOR_ATOP);
            break;
        case dst_atop:
            context_->set_operator(Cairo::OPERATOR_DEST_ATOP);
            break;
        case _xor:
            context_->set_operator(Cairo::OPERATOR_XOR);
            break;
        case plus:
            context_->set_operator(Cairo::OPERATOR_ADD);
            break;
#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 10, 0)
        case multiply:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_MULTIPLY));
            break;
        case screen:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_SCREEN));
            break;
        case overlay:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_OVERLAY));
            break;
        case darken:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_DARKEN));
            break;
        case lighten:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_LIGHTEN));
            break;
        case color_dodge:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_COLOR_DODGE));
            break;
        case color_burn:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_COLOR_BURN));
            break;
        case hard_light:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_HARD_LIGHT));
            break;
        case soft_light:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_SOFT_LIGHT));
            break;
        case difference:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_DIFFERENCE));
            break;
        case exclusion:
            context_->set_operator(static_cast<Cairo::Operator>(CAIRO_OPERATOR_EXCLUSION));
            break;
#else
#warning building against cairo older that 1.10.0, some compositing options are disabled
        case multiply:
        case screen:
        case overlay:
        case darken:
        case lighten:
        case color_dodge:
        case color_burn:
        case hard_light:
        case soft_light:
        case difference:
        case exclusion:
            break;
#endif
        case contrast:
        case minus:
        case invert:
        case invert_rgb:
        case grain_merge:
        case grain_extract:
        case hue:
        case saturation:
        case _color:
        case _value:
        case color_spin:
            break;
        }
    }
    
    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;

                    MAPNIK_LOG_WARN(cairo_renderer) << "Curve 3 not implemented";

                    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
                {
                    MAPNIK_LOG_WARN(cairo_renderer) << "Unimplemented drawing command: " << cm;
                    move_to(x, y);
                }
            }
            else if (agg::is_close(cm))
            {
                close_path();
            }
            else
            {
                MAPNIK_LOG_WARN(cairo_renderer) << "Unimplemented path command: " << cm;
            }
        }
    }

    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.center.x;
        double sy = path.center.y;

        path.rewind();

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

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

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

            glyph_ptr glyph = faces->get_glyph(c->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(c->format->halo_radius);
                set_line_join(ROUND_JOIN);
                set_color(c->format->halo_fill);
                stroke();
                set_color(c->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_(boost::make_shared<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()))
{
    MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: Scale=" << m.scale();
}

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)
{
    MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: Start map processing bbox=" << map.get_current_extent();

#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();
#else
#warning building against cairo older that 1.6.0, map clipping is disabled
#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& )
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: End map processing";
    }

    template <>
        void cairo_renderer<Cairo::Surface>::end_map_processing(Map const& )
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: End map processing";

        context_->show_page();
    }

    void cairo_renderer_base::start_layer_processing(layer const& lay, box2d<double> const& query_extent)
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: Start processing layer=" << lay.name() ;
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: -- datasource=" << lay.datasource().get();
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: -- query_extent=" << query_extent;

        if (lay.clear_label_cache())
        {
            detector_.clear();
        }
        query_extent_ = query_extent;
    }

    void cairo_renderer_base::end_layer_processing(layer const&)
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: End layer processing";
    }

    void cairo_renderer_base::start_style_processing(feature_type_style const& st)
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer:start style processing";
    }

    void cairo_renderer_base::end_style_processing(feature_type_style const& st)
    {
        MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer:end style processing";
    }

    void cairo_renderer_base::process(polygon_symbolizer const& sym,
                                      mapnik::feature_impl & feature,
                                      proj_transform const& prj_trans)
    {
        cairo_context context(context_);
        context.set_operator(sym.comp_op());
        context.set_color(sym.get_fill(), sym.get_opacity());

        agg::trans_affine tr;
        evaluate_transform(tr, feature, sym.get_transform());

        typedef boost::mpl::vector<clip_poly_tag,transform_tag,affine_transform_tag,smooth_tag> conv_types;
        vertex_converter<box2d<double>, cairo_context, polygon_symbolizer,
                         CoordTransform, proj_transform, agg::trans_affine, conv_types>
            converter(query_extent_,context,sym,t_,prj_trans,tr,1.0);

        if (sym.clip()) converter.set<clip_poly_tag>(); //optional clip (default: true)
        converter.set<transform_tag>(); //always transform
        converter.set<affine_transform_tag>();
        if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter

        BOOST_FOREACH( geometry_type & geom, feature.paths())
        {
            if (geom.num_points() > 2)
            {
                converter.apply(geom);
            }
        }
        // fill polygon
        context.fill();
    }

    void cairo_renderer_base::process(building_symbolizer const& sym,
                                      mapnik::feature_impl & feature,
                                      proj_transform const& prj_trans)
    {
        typedef coord_transform<CoordTransform,geometry_type> path_type;

        cairo_context context(context_);
        context.set_operator(sym.comp_op());
        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 = result.to_double(); //scale_factor is always 1.0 atm
        }

        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_impl & feature,
                                      proj_transform const& prj_trans)
    {
        cairo_context context(context_);
        mapnik::stroke const& stroke_ = sym.get_stroke();
        context.set_operator(sym.comp_op());

        context.set_color(stroke_.get_color(), stroke_.get_opacity());
        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());
        if (stroke_.has_dash())
        {
            context.set_dash(stroke_.get_dash_array());
        }

        agg::trans_affine tr;
        evaluate_transform(tr, feature, sym.get_transform());

        typedef boost::mpl::vector<clip_line_tag,transform_tag, offset_transform_tag, affine_transform_tag, smooth_tag> conv_types;
        vertex_converter<box2d<double>, cairo_context, line_symbolizer,
                         CoordTransform, proj_transform, agg::trans_affine, conv_types>
            converter(query_extent_,context,sym,t_,prj_trans,tr,1.0);

        if (sym.clip()) converter.set<clip_line_tag>(); // optional clip (default: true)
        converter.set<transform_tag>(); // always transform

        if (fabs(sym.offset()) > 0.0) converter.set<offset_transform_tag>(); // parallel offset
        converter.set<affine_transform_tag>(); // optional affine transform
        if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter

        BOOST_FOREACH( geometry_type & geom, feature.paths())
        {
            if (geom.num_points() > 1)
            {
                converter.apply(geom);
            }
        }
        // stroke
        context.stroke();
    }

    void cairo_renderer_base::render_marker(pixel_position const& pos, marker const& marker, const agg::trans_affine & tr, double opacity, bool recenter)

    {
        cairo_context context(context_);

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

            agg::trans_affine mtx = tr;

            if (recenter)
            {
                coord<double,2> c = bbox.center();
                // center the svg marker on '0,0'
                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(pos.x+0.5 * marker.width(), pos.y+0.5 * marker.height());
            }

            typedef coord_transform<CoordTransform,geometry_type> path_type;
            agg::trans_affine transform;
            mapnik::path_ptr vmarker = *marker.get_vector_data();
            using namespace mapnik::svg;
            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();

                transform = attr.transform;
                transform *= mtx;

                // TODO - this 'is_valid' check is not used in the AGG renderer and also
                // appears to lead to bogus results with
                // tests/data/good_maps/markers_symbolizer_lines_file.xml
                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)
                    {
                        double fill_opacity = attr.opacity * opacity * attr.fill_color.opacity();
                        context.set_color(attr.fill_color.r,attr.fill_color.g,attr.fill_color.b, fill_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)
                    {
                        double stroke_opacity = attr.opacity * opacity * attr.stroke_color.opacity();
                        context.set_color(attr.stroke_color.r,attr.stroke_color.g,attr.stroke_color.b, stroke_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(pos.x, pos.y, **marker.get_bitmap_data(), opacity);
        }
    }

    void cairo_renderer_base::process(point_symbolizer const& sym,
                                      mapnik::feature_impl & 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>());
        }

        agg::trans_affine mtx;
        evaluate_transform(mtx, feature, sym.get_image_transform());

        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))
                {
                    render_marker(pixel_position(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_impl & 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_, query_extent_);
        cairo_context context(context_);
        context.set_operator(sym.comp_op());

        while (helper.next())
        {
            placements_type &placements = helper.placements();
            for (unsigned int ii = 0; ii < placements.size(); ++ii)
            {
                pixel_position marker_pos = helper.get_marker_position(placements[ii]);
                render_marker(marker_pos,
                              helper.get_marker(), helper.get_image_transform(),
                              sym.get_opacity());
                context.add_text(placements[ii], face_manager_, font_manager_);
            }
        }
    }

    void cairo_renderer_base::process(line_pattern_symbolizer const& sym,
                                      mapnik::feature_impl & feature,
                                      proj_transform const& prj_trans)
    {
        typedef agg::conv_clip_polyline<geometry_type> clipped_geometry_type;
        typedef coord_transform<CoordTransform,clipped_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_);
        context.set_operator(sym.comp_op());
        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 & geom = feature.get_geometry(i);

            if (geom.num_points() > 1)
            {
                clipped_geometry_type clipped(geom);
                clipped.clip_box(query_extent_.minx(),query_extent_.miny(),query_extent_.maxx(),query_extent_.maxy());
                path_type path(t_,clipped,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_impl & feature,
                                      proj_transform const& prj_trans)
    {
        cairo_context context(context_);
        context.set_operator(sym.comp_op());

        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);

        agg::trans_affine tr;
        evaluate_transform(tr, feature, sym.get_transform());

        typedef boost::mpl::vector<clip_poly_tag,transform_tag,affine_transform_tag,smooth_tag> conv_types;
        vertex_converter<box2d<double>, cairo_context, polygon_pattern_symbolizer,
                         CoordTransform, proj_transform, agg::trans_affine, conv_types>
            converter(query_extent_,context,sym,t_,prj_trans,tr,1.0);

        if (sym.clip()) converter.set<clip_poly_tag>(); //optional clip (default: true)
        converter.set<transform_tag>(); //always transform
        converter.set<affine_transform_tag>();
        if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter

        BOOST_FOREACH( geometry_type & geom, feature.paths())
        {
            if (geom.num_points() > 2)
            {
                converter.apply(geom);
            }
        }

        // fill polygon
        context.fill();
    }

    void cairo_renderer_base::process(raster_symbolizer const& sym,
                                      mapnik::feature_impl & 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_);
                context.set_operator(sym.comp_op());
                //TODO -- support for advanced image merging
                context.add_image(start_x, start_y, target.data_, sym.get_opacity());
            }
        }
    }

    void cairo_renderer_base::process(markers_symbolizer const& sym,
                                      mapnik::feature_impl & feature,
                                      proj_transform const& prj_trans)
    {
        cairo_context context(context_);
        context.set_operator(sym.comp_op());
        double scale_factor_ = 1;

        typedef agg::conv_clip_polyline<geometry_type> clipped_geometry_type;
        typedef coord_transform<CoordTransform,clipped_geometry_type> path_type;

        agg::trans_affine tr;
        evaluate_transform(tr, feature, sym.get_image_transform());

        // TODO - use this?
        //tr = agg::trans_affine_scaling(scale_factor_) * tr;
        std::string filename = path_processor_type::evaluate(*sym.get_filename(), feature);
        marker_placement_e placement_method = sym.get_marker_placement();
        marker_type_e marker_type = sym.get_marker_type();
        metawriter_with_properties writer = sym.get_metawriter();

        if (!filename.empty())
        {
            boost::optional<marker_ptr> mark = mapnik::marker_cache::instance()->find(filename, true);
            if (mark && *mark)
            {
                if (!(*mark)->is_vector())
                {
                    MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer_base: markers_symbolizer does not yet support non-SVG markers";

                    return;
                }
                boost::optional<path_ptr> marker = (*mark)->get_vector_data();
                box2d<double> const& bbox = (*marker)->bounding_box();
                double x1 = bbox.minx();
                double y1 = bbox.miny();
                double x2 = bbox.maxx();
                double y2 = bbox.maxy();
                double w = (*mark)->width();
                double h = (*mark)->height();

                agg::trans_affine recenter = agg::trans_affine_translation(-0.5*(x1+x2),-0.5*(y1+y2));
                tr.transform(&x1,&y1);
                tr.transform(&x2,&y2);
                box2d<double> extent(x1,y1,x2,y2);
                using namespace mapnik::svg;

                for (unsigned i=0; i<feature.num_geometries(); ++i)
                {
                    geometry_type & geom = feature.get_geometry(i);
                    // TODO - merge this code with point_symbolizer rendering
                    if (placement_method == MARKER_POINT_PLACEMENT || geom.num_points() <= 1)
                    {
                        double x;
                        double y;
                        double z=0;
                        geom.label_interior_position(&x, &y);
                        prj_trans.backward(x,y,z);
                        t_.forward(&x,&y);
                        extent.re_center(x,y);

                        if (sym.get_allow_overlap() ||
                            detector_.has_placement(extent))
                        {
                            render_marker(pixel_position(x - 0.5 * w, y - 0.5 * h) ,**mark, tr, sym.get_opacity());

                            // TODO - impl this for markers?
                            //if (!sym.get_ignore_placement())
                            //    detector_.insert(label_ext);
                            metawriter_with_properties writer = sym.get_metawriter();
                            if (writer.first) writer.first->add_box(extent, feature, t_, writer.second);
                        }
                    }
                    else
                    {
                        clipped_geometry_type clipped(geom);
                        clipped.clip_box(query_extent_.minx(),query_extent_.miny(),query_extent_.maxx(),query_extent_.maxy());
                        path_type path(t_,clipped,prj_trans);
                        markers_placement<path_type, label_collision_detector4> placement(path, extent, detector_,
                                                                                          sym.get_spacing() * scale_factor_,
                                                                                          sym.get_max_error(),
                                                                                          sym.get_allow_overlap());
                        double x, y, angle;

                        while (placement.get_point(&x, &y, &angle))
                        {
                            agg::trans_affine matrix = recenter * tr * agg::trans_affine_rotation(angle) * agg::trans_affine_translation(x, y);
                            render_marker(pixel_position(x - 0.5 * w, y - 0.5 * h), **mark, matrix, sym.get_opacity(),false);

                            if (writer.first)
                            {
                                //writer.first->add_box(label_ext, feature, t_, writer.second);
                                MAPNIK_LOG_WARN(cairo_renderer) << "metawriter not yet supported for LINE placement";
                            }
                        }
                    }
                    context.fill();
                }
            }
        }
        else
        {
            color const& fill_ = sym.get_fill();
            stroke const& stroke_ = sym.get_stroke();
            color const& col = stroke_.get_color();
            double strk_width = stroke_.get_width();
            double w = sym.get_width();
            double h = sym.get_height();
            double rx = w/2.0;
            double ry = h/2.0;

            arrow arrow_;
            box2d<double> extent;

            double dx = w + (2*strk_width);
            double dy = h + (2*strk_width);

            if (marker_type == MARKER_ARROW)
            {
                extent = arrow_.extent();
                double x1 = extent.minx();
                double y1 = extent.miny();
                double x2 = extent.maxx();
                double y2 = extent.maxy();
                tr.transform(&x1,&y1);
                tr.transform(&x2,&y2);
                extent.init(x1,y1,x2,y2);
            }
            else
            {
                double x1 = -1 *(dx);
                double y1 = -1 *(dy);
                double x2 = dx;
                double y2 = dy;
                tr.transform(&x1,&y1);
                tr.transform(&x2,&y2);
                extent.init(x1,y1,x2,y2);
            }

            double x;
            double y;
            double z=0;

            agg::path_storage marker;

            for (unsigned i=0; i<feature.num_geometries(); ++i)
            {
                geometry_type & geom = feature.get_geometry(i);
                if (placement_method == MARKER_POINT_PLACEMENT || geom.num_points() <= 1)
                {
                    geom.label_position(&x,&y);
                    prj_trans.backward(x,y,z);
                    t_.forward(&x,&y);
                    int px = int(floor(x - 0.5 * dx));
                    int py = int(floor(y - 0.5 * dy));
                    box2d<double> label_ext (px, py, px + dx +1, py + dy +1);
                    if (sym.get_allow_overlap() ||
                        detector_.has_placement(label_ext))
                    {
                        agg::ellipse c(x, y, rx, ry);
                        marker.concat_path(c);
                        context.set_color(fill_,sym.get_opacity());
                        context.add_agg_path(marker);
                        context.fill();

                        if (strk_width)
                        {
                            //context.restore();
                            context.set_color(col,stroke_.get_opacity());
                            context.set_line_width(stroke_.get_width());
                            if (stroke_.has_dash())
                            {
                                context.set_dash(stroke_.get_dash_array());
                            }
                            context.add_agg_path(marker);
                            context.stroke();
                        }
                        if (!sym.get_ignore_placement())
                            detector_.insert(label_ext);
                        if (writer.first) writer.first->add_box(label_ext, feature, t_, writer.second);
                    }
                }
                else
                {
                    if (marker_type == MARKER_ARROW)
                        marker.concat_path(arrow_);

                    clipped_geometry_type clipped(geom);
                    clipped.clip_box(query_extent_.minx(),query_extent_.miny(),query_extent_.maxx(),query_extent_.maxy());
                    path_type path(t_,clipped,prj_trans);
                    markers_placement<path_type, label_collision_detector4> placement(path, extent, detector_,
                                                                                      sym.get_spacing() * scale_factor_,
                                                                                      sym.get_max_error(),
                                                                                      sym.get_allow_overlap());
                    double x_t, y_t, angle;

                    while (placement.get_point(&x_t, &y_t, &angle))
                    {
                        agg::trans_affine matrix;

                        if (marker_type == MARKER_ELLIPSE)
                        {
                            agg::ellipse c(x_t, y_t, rx, ry);
                            marker.concat_path(c);
                            agg::trans_affine matrix;
                            matrix *= agg::trans_affine_translation(-x_t,-y_t);
                            matrix *= agg::trans_affine_rotation(angle);
                            matrix *= agg::trans_affine_translation(x_t,y_t);
                            marker.transform(matrix);
                        }
                        else
                        {
                            matrix = tr * agg::trans_affine_rotation(angle) * agg::trans_affine_translation(x_t, y_t);
                        }

                        // TODO
                        if (writer.first)
                        {
                            //writer.first->add_box(label_ext, feature, t_, writer.second);
                            MAPNIK_LOG_WARN(cairo_renderer) << "metawriter not yet supported for LINE placement";
                        }

                        agg::conv_transform<agg::path_storage, agg::trans_affine> trans(marker, matrix);
                        context.set_color(fill_,sym.get_opacity());
                        context.add_agg_path(trans);
                        context.fill();

                        if (strk_width)
                        {
                            context.set_color(col,stroke_.get_opacity());
                            context.set_line_width(stroke_.get_width());
                            if (stroke_.has_dash())
                            {
                                context.set_dash(stroke_.get_dash_array());
                            }
                            context.add_agg_path(trans);
                            context.stroke();
                        }
                    }
                }
            }
        }
    }

    void cairo_renderer_base::process(text_symbolizer const& sym,
                                      mapnik::feature_impl & 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_, query_extent_);

        cairo_context context(context_);
        context.set_operator(sym.comp_op());

        while (helper.next()) {
            placements_type &placements = helper.placements();
            for (unsigned int ii = 0; ii < placements.size(); ++ii)
            {
                context.add_text(placements[ii], face_manager_, font_manager_);
            }
        }
    }

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

#endif