Fixes blend + color filter (#55411)

fixes flutter/flutter#155456

Thanks @jason-simmons for identifying the fix.

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Author: gaaclarke

impeller/display_list/aiks_dl_blend_unittests.cc

@@ -194,6 +194,58 @@ TEST_P(AiksTest, PaintBlendModeIsRespected) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+// Compare results with https://api.flutter.dev/flutter/dart-ui/BlendMode.html
+TEST_P(AiksTest, ImageFilterBlend) {
+  bool has_color_filter = true;
+  auto callback = [&]() -> sk_sp<DisplayList> {
+    if (AiksTest::ImGuiBegin("Controls", nullptr,
+                             ImGuiWindowFlags_AlwaysAutoResize)) {
+      ImGui::Checkbox("has color filter", &has_color_filter);
+      ImGui::End();
+    }
+
+    DisplayListBuilder builder;
+    builder.Scale(GetContentScale().x, GetContentScale().y);
+
+    auto src_image =
+        DlImageImpeller::Make(CreateTextureForFixture("blend_mode_src.png"));
+    auto dst_image =
+        DlImageImpeller::Make(CreateTextureForFixture("blend_mode_dst.png"));
+
+    std::vector<DlBlendMode> blend_modes = {
+        DlBlendMode::kSrc,     DlBlendMode::kSrcATop, DlBlendMode::kSrcOver,
+        DlBlendMode::kSrcIn,   DlBlendMode::kSrcOut,  DlBlendMode::kDst,
+        DlBlendMode::kDstATop, DlBlendMode::kDstOver, DlBlendMode::kDstIn,
+        DlBlendMode::kDstOut,  DlBlendMode::kClear,   DlBlendMode::kXor};
+
+    for (uint32_t i = 0; i < blend_modes.size(); ++i) {
+      builder.Save();
+      builder.Translate((i % 5) * 200, (i / 5) * 200);
+      builder.Scale(0.4, 0.4);
+      {
+        DlPaint dstPaint;
+        builder.DrawImage(dst_image, {0, 0}, DlImageSampling::kMipmapLinear,
+                          &dstPaint);
+      }
+      {
+        DlPaint srcPaint;
+        srcPaint.setBlendMode(blend_modes[i]);
+        if (has_color_filter) {
+          std::shared_ptr<const DlColorFilter> color_filter =
+              DlBlendColorFilter::Make(DlColor::RGBA(0.9, 0.5, 0.0, 1.0),
+                                       DlBlendMode::kSrcIn);
+          srcPaint.setColorFilter(color_filter);
+        }
+        builder.DrawImage(src_image, {0, 0}, DlImageSampling::kMipmapLinear,
+                          &srcPaint);
+      }
+      builder.Restore();
+    }
+    return builder.Build();
+  };
+  ASSERT_TRUE(OpenPlaygroundHere(callback));
+}
+
 // Bug: https://github.com/flutter/flutter/issues/142549
 TEST_P(AiksTest, BlendModePlusAlphaWideGamut) {
   EXPECT_EQ(GetContext()->GetCapabilities()->GetDefaultColorFormat(),

impeller/entity/contents/filters/blend_filter_contents.cc

@@ -454,7 +454,7 @@ std::optional<Entity> BlendFilterContents::CreateForegroundPorterDuffBlend(
                                  BlendModeToString(blend_mode)));
 #endif  // IMPELLER_DEBUG
     pass.SetVertexBuffer(std::move(vtx_buffer));
-    auto options = OptionsFromPass(pass);
+    auto options = OptionsFromPassAndEntity(pass, entity);
     options.primitive_type = PrimitiveType::kTriangleStrip;
     pass.SetPipeline(renderer.GetPorterDuffBlendPipeline(options));
 
@@ -505,6 +505,7 @@ std::optional<Entity> BlendFilterContents::CreateForegroundPorterDuffBlend(
 
   Entity sub_entity;
   sub_entity.SetContents(std::move(contents));
+  sub_entity.SetBlendMode(entity.GetBlendMode());
 
   return sub_entity;
 }

testing/impeller_golden_tests_output.txt

@@ -711,6 +711,9 @@ impeller_Play_AiksTest_GradientStrokesRenderCorrectly_Vulkan.png
 impeller_Play_AiksTest_ImageColorSourceEffectTransform_Metal.png
 impeller_Play_AiksTest_ImageColorSourceEffectTransform_OpenGLES.png
 impeller_Play_AiksTest_ImageColorSourceEffectTransform_Vulkan.png
+impeller_Play_AiksTest_ImageFilterBlend_Metal.png
+impeller_Play_AiksTest_ImageFilterBlend_OpenGLES.png
+impeller_Play_AiksTest_ImageFilterBlend_Vulkan.png
 impeller_Play_AiksTest_ImageFilteredSaveLayerWithUnboundedContents_Metal.png
 impeller_Play_AiksTest_ImageFilteredSaveLayerWithUnboundedContents_OpenGLES.png
 impeller_Play_AiksTest_ImageFilteredSaveLayerWithUnboundedContents_Vulkan.png