[Impeller] make sure to render TiledTextureContents if the geometry doesn't fit in the texture's bounds. (#51393)

fixes flutter/flutter#144836

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: gaaclarke

impeller/aiks/aiks_blur_unittests.cc

@@ -1146,5 +1146,40 @@ TEST_P(AiksTest, GaussianBlurMipMapSolidColor) {
 #endif
 }
 
+TEST_P(AiksTest, MaskBlurDoesntStretchContents) {
+  Scalar sigma = 70;
+  auto callback = [&](AiksContext& renderer) -> std::optional<Picture> {
+    if (AiksTest::ImGuiBegin("Controls", nullptr,
+                             ImGuiWindowFlags_AlwaysAutoResize)) {
+      ImGui::SliderFloat("Sigma", &sigma, 0, 500);
+      ImGui::End();
+    }
+    Canvas canvas;
+    canvas.Scale(GetContentScale());
+    canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
+
+    std::shared_ptr<Texture> boston = CreateTextureForFixture("boston.jpg");
+    ColorSource image_source = ColorSource::MakeImage(
+        boston, Entity::TileMode::kRepeat, Entity::TileMode::kRepeat, {}, {});
+
+    canvas.Transform(Matrix::MakeTranslation({100, 100, 0}) *
+                     Matrix::MakeScale({0.5, 0.5, 1.0}));
+    Paint paint = {
+        .color_source = image_source,
+        .mask_blur_descriptor =
+            Paint::MaskBlurDescriptor{
+                .style = FilterContents::BlurStyle::kNormal,
+                .sigma = Sigma(sigma),
+            },
+    };
+    canvas.DrawRect(
+        Rect::MakeXYWH(0, 0, boston->GetSize().width, boston->GetSize().height),
+        paint);
+
+    return canvas.EndRecordingAsPicture();
+  };
+  ASSERT_TRUE(OpenPlaygroundHere(callback));
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/aiks/paint.cc

@@ -183,7 +183,6 @@ std::shared_ptr<FilterContents> Paint::MaskBlurDescriptor::CreateMaskBlur(
   }
   color_source_contents->SetGeometry(
       Geometry::MakeRect(*expanded_local_bounds));
-
   std::shared_ptr<Contents> color_contents = color_source_contents;
 
   /// 4. Apply the user set color filter on the GPU, if applicable.

impeller/entity/contents/tiled_texture_contents.cc

@@ -228,8 +228,12 @@ std::optional<Snapshot> TiledTextureContents::RenderToSnapshot(
     bool msaa_enabled,
     int32_t mip_count,
     const std::string& label) const {
+  std::optional<Rect> geometry_coverage = GetGeometry()->GetCoverage({});
   if (GetInverseEffectTransform().IsIdentity() &&
-      GetGeometry()->IsAxisAlignedRect()) {
+      GetGeometry()->IsAxisAlignedRect() &&
+      (!geometry_coverage.has_value() ||
+       Rect::MakeSize(texture_->GetSize())
+           .Contains(geometry_coverage.value()))) {
     auto coverage = GetCoverage(entity);
     if (!coverage.has_value()) {
       return std::nullopt;

testing/impeller_golden_tests_output.txt

@@ -528,6 +528,9 @@ impeller_Play_AiksTest_ImageFilteredUnboundedSaveLayerWithUnboundedContents_Vulk
 impeller_Play_AiksTest_LinearToSrgbFilterSubpassCollapseOptimization_Metal.png
 impeller_Play_AiksTest_LinearToSrgbFilterSubpassCollapseOptimization_OpenGLES.png
 impeller_Play_AiksTest_LinearToSrgbFilterSubpassCollapseOptimization_Vulkan.png
+impeller_Play_AiksTest_MaskBlurDoesntStretchContents_Metal.png
+impeller_Play_AiksTest_MaskBlurDoesntStretchContents_OpenGLES.png
+impeller_Play_AiksTest_MaskBlurDoesntStretchContents_Vulkan.png
 impeller_Play_AiksTest_MaskBlurTexture_Metal.png
 impeller_Play_AiksTest_MaskBlurTexture_OpenGLES.png
 impeller_Play_AiksTest_MaskBlurTexture_Vulkan.png