214 lines
9 KiB
C++
214 lines
9 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2021 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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// mapnik
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#include <mapnik/image_compositing.hpp>
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#include <mapnik/image.hpp>
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#include <mapnik/image_any.hpp>
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#include <mapnik/safe_cast.hpp>
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#include <mapnik/util/const_rendering_buffer.hpp>
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#include <mapnik/warning.hpp>
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MAPNIK_DISABLE_WARNING_PUSH
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#include <mapnik/warning_ignore.hpp>
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#include <boost/assign/list_of.hpp>
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#include <boost/bimap.hpp>
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MAPNIK_DISABLE_WARNING_POP
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#include <mapnik/warning.hpp>
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MAPNIK_DISABLE_WARNING_PUSH
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#include <mapnik/warning_ignore_agg.hpp>
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#include "agg_rendering_buffer.h"
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#include "agg_rasterizer_scanline_aa.h"
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#include "agg_scanline_u.h"
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#include "agg_renderer_scanline.h"
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#include "agg_pixfmt_rgba.h"
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#include "agg_pixfmt_gray.h"
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#include "agg_color_rgba.h"
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MAPNIK_DISABLE_WARNING_POP
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namespace mapnik {
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using comp_op_lookup_type = boost::bimap<composite_mode_e, std::string>;
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static const comp_op_lookup_type comp_lookup =
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boost::assign::list_of<comp_op_lookup_type::relation>(clear, "clear")(src, "src")(dst, "dst")(src_over, "src-over")(
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dst_over,
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"dst-over")(src_in, "src-in")(dst_in, "dst-in")(src_out, "src-out")(dst_out, "dst-out")(src_atop, "src-atop")(
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dst_atop,
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"dst-atop")(_xor, "xor")(plus, "plus")(minus, "minus")(multiply, "multiply")(screen, "screen")(overlay, "overlay")(
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darken,
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"darken")(lighten, "lighten")(color_dodge, "color-dodge")(color_burn, "color-burn")(hard_light, "hard-light")(
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soft_light,
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"soft-light")(difference, "difference")(exclusion, "exclusion")(contrast, "contrast")(invert, "invert")(
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invert_rgb,
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"invert-rgb")(grain_merge, "grain-merge")(grain_extract, "grain-extract")(hue, "hue")(saturation, "saturation")(
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_color,
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"color")(_value, "value")(linear_dodge, "linear-dodge")(linear_burn, "linear-burn")(divide, "divide");
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std::optional<composite_mode_e> comp_op_from_string(std::string const& name)
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{
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std::optional<composite_mode_e> mode;
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comp_op_lookup_type::right_const_iterator right_iter = comp_lookup.right.find(name);
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if (right_iter != comp_lookup.right.end())
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{
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mode = right_iter->second;
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}
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return mode;
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}
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std::optional<std::string> comp_op_to_string(composite_mode_e comp_op)
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{
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std::optional<std::string> mode;
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comp_op_lookup_type::left_const_iterator left_iter = comp_lookup.left.find(comp_op);
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if (left_iter != comp_lookup.left.end())
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{
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mode = left_iter->second;
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}
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return mode;
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}
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/*
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Note: the difference between agg::pixfmt_rgba32 and agg:pixfmt_rgba32_pre is subtle.
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From http://www.antigrain.com/news/release_notes/v22.agdoc.html:
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Format agg::pixfmt_rgba32 is the main and the fastest pixel format and it's supposed to be used in most cases. But it
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always uses plain colors as input and produces pre-multiplied result on the canvas. It has even less number of
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calculations than agg::pixfmt_rgba32_pre. Format agg::pixfmt_rgba32_plain is slow because of division operations. APIs
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allowing for alpha-blending require premultiplied colors. Besides, if you display RGBA with RGB API (that is, without
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alpha, like WinAPI BitBlt), the colors still must be premultiplied. Note that the formulas in agg::pixfmt_rgba32 and
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agg::pixfmt_rgb24 are exactly the same! So, premultiplied colors are more natural and agg::pixfmt_rgba32_plain is rather
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useless.
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Format agg::pixfmt_rgba32_pre is a bit slower than agg::pixfmt_rgba32 because of additional "cover" values, i.e.
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secondary alphas, that are to be mixed with the source premultiplied color. That spoils the beauty of the premultiplied
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colors idea. But the "cover" values are important because there can be other color spaces and color types that don't
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have any "alpha" at all, or the alpha is incompatible with integral types. So, the "cover" is a secondary, uniform alpha
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in range of 0…255, used specifically for anti-aliasing purposes. One needs to consider this issue when transforming
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images. Actually, all RGBA images are supposed to be in the premultiplied color space and the result of filtering is
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also premultiplied. Since the resulting colors of the filtered images are the source for the renderers, one should use
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the premultiplied renderers, that is, agg::pixfmt_rgba32_pre, or the new one, agg::pixfmt_rgb24_pre. But it's important
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only if images are translucent, that is, have actual alpha channel.
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For example, if you generate some pattern with AGG (premultiplied) and would like to use it for filling, you'll need to
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use agg::pixfmt_rgba32_pre. If you use agg::span_image_filter_rgb24_gamma_bilinear (that is, RGB for input) and draw it
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on the RGBA canvas, you still need to use agg::pixfmt_rgba32_pre as the destination canvas. The only thing you need is
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to premultiply the background color used out of bounds.
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*/
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template<>
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MAPNIK_DECL void
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composite(image_rgba8& dst, image_rgba8 const& src, composite_mode_e mode, float opacity, int dx, int dy)
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{
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using color = agg::rgba8;
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using order = agg::order_rgba;
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using const_rendering_buffer = util::rendering_buffer<image_rgba8>;
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using blender_type = agg::comp_op_adaptor_rgba_pre<color, order>;
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using pixfmt_type = agg::pixfmt_custom_blend_rgba<blender_type, agg::rendering_buffer>;
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using renderer_type = agg::renderer_base<pixfmt_type>;
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agg::rendering_buffer dst_buffer(dst.bytes(),
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safe_cast<unsigned>(dst.width()),
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safe_cast<unsigned>(dst.height()),
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safe_cast<int>(dst.row_size()));
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const_rendering_buffer src_buffer(src);
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pixfmt_type pixf(dst_buffer);
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pixf.comp_op(static_cast<agg::comp_op_e>(mode));
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agg::pixfmt_alpha_blend_rgba<agg::blender_rgba32_pre, const_rendering_buffer, agg::pixel32_type> pixf_mask(
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src_buffer);
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#ifdef MAPNIK_DEBUG
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if (!src.get_premultiplied())
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{
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throw std::runtime_error("SOURCE MUST BE PREMULTIPLIED FOR COMPOSITING!");
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}
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if (!dst.get_premultiplied())
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{
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throw std::runtime_error("DESTINATION MUST BE PREMULTIPLIED FOR COMPOSITING!");
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}
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#endif
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renderer_type ren(pixf);
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ren.blend_from(pixf_mask, 0, dx, dy, safe_cast<agg::cover_type>(255 * opacity));
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}
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template<>
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MAPNIK_DECL void
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composite(image_gray32f& dst, image_gray32f const& src, composite_mode_e /*mode*/, float /*opacity*/, int dx, int dy)
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{
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using const_rendering_buffer = util::rendering_buffer<image_gray32f>;
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using src_pixfmt_type = agg::pixfmt_alpha_blend_gray<agg::blender_gray<agg::gray32>, const_rendering_buffer, 1, 0>;
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using dst_pixfmt_type = agg::pixfmt_alpha_blend_gray<agg::blender_gray<agg::gray32>, agg::rendering_buffer, 1, 0>;
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using renderer_type = agg::renderer_base<dst_pixfmt_type>;
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agg::rendering_buffer dst_buffer(dst.bytes(),
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safe_cast<unsigned>(dst.width()),
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safe_cast<unsigned>(dst.height()),
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safe_cast<int>(dst.width()));
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const_rendering_buffer src_buffer(src);
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dst_pixfmt_type pixf(dst_buffer);
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src_pixfmt_type pixf_mask(src_buffer);
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renderer_type ren(pixf);
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ren.copy_from(pixf_mask, 0, dx, dy);
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}
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namespace detail {
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struct composite_visitor
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{
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composite_visitor(image_any const& src, composite_mode_e mode, float opacity, int dx, int dy)
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: src_(src)
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, mode_(mode)
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, opacity_(opacity)
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, dx_(dx)
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, dy_(dy)
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{}
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template<typename T>
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void operator()(T& dst) const
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{
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throw std::runtime_error("Error: Composite with " + std::string(typeid(dst).name()) + " is not supported");
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}
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void operator()(image_rgba8& dst) const { composite(dst, util::get<image_rgba8>(src_), mode_, opacity_, dx_, dy_); }
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void operator()(image_gray32f& dst) const
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{
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composite(dst, util::get<image_gray32f>(src_), mode_, opacity_, dx_, dy_);
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}
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private:
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image_any const& src_;
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composite_mode_e mode_;
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float opacity_;
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int dx_;
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int dy_;
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};
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} // namespace detail
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template<>
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MAPNIK_DECL void composite(image_any& dst, image_any const& src, composite_mode_e mode, float opacity, int dx, int dy)
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{
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util::apply_visitor(detail::composite_visitor(src, mode, opacity, dx, dy), dst);
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}
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} // namespace mapnik
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