From 0e0c4aa82c653955b45d8a1e7295232f24b46047 Mon Sep 17 00:00:00 2001
From: Alberto Valverde <alberto@meteogrid.com>
Date: Thu, 12 May 2011 18:09:03 +0000
Subject: [PATCH] integrated test case from #759

---
 src/agg/process_raster_symbolizer.cpp        |   2 +
 tests/data/raster/white-alpha.png            | Bin 0 -> 150 bytes
 tests/python_tests/raster_symbolizer_test.py |  38 +++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100755 tests/data/raster/white-alpha.png

diff --git a/src/agg/process_raster_symbolizer.cpp b/src/agg/process_raster_symbolizer.cpp
index 84c6a1964..a7468abaf 100644
--- a/src/agg/process_raster_symbolizer.cpp
+++ b/src/agg/process_raster_symbolizer.cpp
@@ -63,6 +63,8 @@ void agg_renderer<T>::process(raster_symbolizer const& sym,
             
             if (sym.get_scaling() == "bilinear8"){
                 scale_image_bilinear8<image_data_32>(target,raster->data_, err_offs_x, err_offs_y);
+            } else if (sym.get_scaling() == "bilinear_old") {
+                scale_image_bilinear_old<image_data_32>(target,raster->data_, err_offs_x, err_offs_y);
             } else {
                 scaling_method_e scaling_method = get_scaling_method_by_name(sym.get_scaling());
                 scale_image_agg<image_data_32>(target,raster->data_, (scaling_method_e)scaling_method, scale_factor, err_offs_x, err_offs_y, sym.calculate_filter_factor());
diff --git a/tests/data/raster/white-alpha.png b/tests/data/raster/white-alpha.png
new file mode 100755
index 0000000000000000000000000000000000000000..40ed38154757475155501a01c44906c1c4b7de44
GIT binary patch
literal 150
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zL7P`q%YY)B1s;*b3=G`DAk4@xYmNj^kiEpy*OmP?D-SQXX?M#Hd!Ue*r;B3<$Mxht
m|NsB5VN*G9q=Aitn}Ok-AM+9^H9uCM3I<PCKbLh*2~7aX-X(1S

literal 0
HcmV?d00001

diff --git a/tests/python_tests/raster_symbolizer_test.py b/tests/python_tests/raster_symbolizer_test.py
index 3449ddda0..24c7cc456 100644
--- a/tests/python_tests/raster_symbolizer_test.py
+++ b/tests/python_tests/raster_symbolizer_test.py
@@ -94,3 +94,41 @@ def test_load_save_map():
     assert 'RasterSymbolizer' in out_map
     assert 'RasterColorizer' in out_map
     assert 'stop' in out_map
+
+def test_raster_with_alpha_blends_correctly_with_background():
+    WIDTH = 500
+    HEIGHT = 500
+
+    map = mapnik2.Map(WIDTH, HEIGHT)
+    WHITE = mapnik2.Color(255, 255, 255)
+    map.background = WHITE
+
+    style = mapnik2.Style()
+    rule = mapnik2.Rule()
+    symbolizer = mapnik2.RasterSymbolizer()
+    #XXX: This fixes it, see http://trac.mapnik.org/ticket/759#comment:3
+    #     (and remove comment when this test passes)
+    #symbolizer.scaling="bilinear_old"
+
+    rule.symbols.append(symbolizer)
+    style.rules.append(rule)
+
+    map.append_style('raster_style', style)
+
+    map_layer = mapnik2.Layer('test_layer')
+    filepath = '../data/raster/white-alpha.png'
+    map_layer.datasource = mapnik2.Gdal(file=filepath)
+    map_layer.styles.append('raster_style')
+    map.layers.append(map_layer)
+
+    map.zoom_all()
+
+    mim = mapnik2.Image(WIDTH, HEIGHT)
+
+    mapnik2.render(map, mim)
+    save_data('test_raster_with_alpha_blends_correctly_with_background.png',
+              mim.tostring('png'))
+    imdata = mim.tostring()
+    # All white is expected
+    assert contains_word('\xff\xff\xff\xff', imdata)
+