Add SVG renderer unit test - both inline and css styled octocat result in identical image (ref PR #4123)

test/data

@@ -1 +1 @@
-Subproject commit c3982b76602bcbfea6403793ac2f3fab44552270
+Subproject commit e83b7f7c6d2d646a638bba404a0d637609722a09

test/unit/svg/svg_renderer_test.cpp

@@ -0,0 +1,109 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2020 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
+ *
+ *****************************************************************************/
+
+#include "catch.hpp"
+
+#include <mapnik/debug.hpp>
+#include <mapnik/marker.hpp>
+#include <mapnik/marker_cache.hpp>
+#include <mapnik/image_util.hpp>
+#include <mapnik/svg/svg_parser.hpp>
+#include <mapnik/svg/svg_converter.hpp>
+#include <mapnik/svg/svg_path_adapter.hpp>
+#include <mapnik/svg/svg_renderer_agg.hpp>
+#include <mapnik/svg/svg_path_attributes.hpp>
+#include <boost/range/combine.hpp>
+
+#pragma GCC diagnostic push
+#include <mapnik/warning_ignore_agg.hpp>
+#include "agg_rasterizer_scanline_aa.h"
+#include "agg_basics.h"
+#include "agg_rendering_buffer.h"
+#include "agg_renderer_base.h"
+#include "agg_pixfmt_rgba.h"
+#include "agg_scanline_u.h"
+#pragma GCC diagnostic pop
+
+namespace
+{
+
+mapnik::image_rgba8 render_svg(std::string const& filename, double scale_factor)
+{
+     using pixfmt = agg::pixfmt_rgba32_pre;
+     using renderer_base = agg::renderer_base<pixfmt>;
+     using renderer_solid = agg::renderer_scanline_aa_solid<renderer_base>;
+
+     agg::rasterizer_scanline_aa<> ras_ptr;
+     agg::scanline_u8 sl;
+     std::shared_ptr<mapnik::marker const> marker = mapnik::marker_cache::instance().find(filename, false);
+     mapnik::marker_svg const& svg = mapnik::util::get<mapnik::marker_svg>(*marker);
+     double svg_width, svg_height ;
+     std::tie(svg_width, svg_height) = svg.dimensions();
+     int image_width = static_cast<int>(std::round(svg_width));
+     int image_height = static_cast<int>(std::round(svg_height));
+
+     mapnik::image_rgba8 im(image_width, image_height, true, true);
+     agg::rendering_buffer buf(im.bytes(), im.width(), im.height(), im.row_size());
+     pixfmt pixf(buf);
+     renderer_base renb(pixf);
+
+     agg::trans_affine mtx = agg::trans_affine_translation(-0.5 * svg_width, -0.5 * svg_height);
+     mtx.scale(scale_factor);
+     mtx.translate(0.5 * svg_width, 0.5 * svg_height);
+
+     mapnik::svg::vertex_stl_adapter<mapnik::svg::svg_path_storage> stl_storage(svg.get_data()->source());
+     mapnik::svg::svg_path_adapter svg_path(stl_storage);
+     mapnik::svg::renderer_agg<mapnik::svg_path_adapter,
+                               mapnik::svg_attribute_type,
+                               renderer_solid,
+                               agg::pixfmt_rgba32_pre > renderer(svg_path,
+                                                                 svg.get_data()->attributes());
+     double opacity = 1.0;
+     renderer.render(ras_ptr, sl, renb, mtx, opacity, {0, 0, svg_width, svg_height});
+     return im;
+}
+
+bool equal(mapnik::image_rgba8 const& im1, mapnik::image_rgba8 const& im2)
+{
+    if (im1.width() != im2.width() || im1.height() != im2.height())
+        return false;
+
+    for(auto tup : boost::combine(im1, im2))
+    {
+        if (boost::get<0>(tup) != boost::get<1>(tup)) return false;
+    }
+    return true;
+}
+}
+
+TEST_CASE("SVG renderer") {
+
+    SECTION("SVG octocat inline/css")
+    {
+        double scale_factor = 1.0;
+        std::string octocat_inline("./test/data/svg/octocat.svg");
+        std::string octocat_css("./test/data/svg/octocat-css.svg");
+        auto image1 = render_svg(octocat_inline, 1.0);
+        auto image2 = render_svg(octocat_css, 1.0);
+        REQUIRE(equal(image1, image2));
+    }
+}