[Impeller] Clip the DrawImageRect source rect to the bounds of the image

impeller/display_list/aiks_dl_basic_unittests.cc

@@ -233,6 +233,26 @@ TEST_P(AiksTest, CanRenderImageRect) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+TEST_P(AiksTest, DrawImageRectSrcOutsideBounds) {
+  DisplayListBuilder builder;
+  auto image = DlImageImpeller::Make(CreateTextureForFixture("kalimba.jpg"));
+
+  // Use a source rect that is partially outside the bounds of the image.
+  auto source_rect = SkRect::MakeXYWH(
+      image->dimensions().fWidth * 0.25f, image->dimensions().fHeight * 0.4f,
+      image->dimensions().fWidth, image->dimensions().fHeight);
+
+  auto dest_rect = SkRect::MakeXYWH(100, 100, 600, 600);
+
+  DlPaint paint;
+  paint.setColor(DlColor::kMidGrey());
+  builder.DrawRect(dest_rect, paint);
+
+  builder.DrawImageRect(image, source_rect, dest_rect,
+                        DlImageSampling::kNearestNeighbor);
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
 TEST_P(AiksTest, CanRenderSimpleClips) {
   DisplayListBuilder builder;
   builder.Scale(GetContentScale().x, GetContentScale().y);

impeller/display_list/canvas.cc

@@ -679,9 +679,28 @@ void Canvas::DrawImageRect(const std::shared_ptr<Texture>& image,
     return;
   }
 
+  std::optional<Rect> clipped_source =
+      source.Intersection(Rect::MakeSize(size));
+  if (!clipped_source) {
+    return;
+  }
+  if (*clipped_source != source) {
+    Scalar sx = dest.GetWidth() / source.GetWidth();
+    Scalar sy = dest.GetHeight() / source.GetHeight();
+    Scalar tx = dest.GetLeft() - source.GetLeft() * sx;
+    Scalar ty = dest.GetTop() - source.GetTop() * sy;
+    // clang-format off
+    Matrix src_to_dest(  sx, 0.0f, 0.0f, 0.0f,
+                       0.0f,   sy, 0.0f, 0.0f,
+                       0.0f, 0.0f, 1.0f, 0.0f,
+                         tx,   ty, 0.0f, 1.0f);
+    // clang-format on
+    dest = clipped_source->TransformBounds(src_to_dest);
+  }
+
   auto texture_contents = TextureContents::MakeRect(dest);
   texture_contents->SetTexture(image);
-  texture_contents->SetSourceRect(source);
+  texture_contents->SetSourceRect(*clipped_source);
   texture_contents->SetStrictSourceRect(src_rect_constraint ==
                                         SourceRectConstraint::kStrict);
   texture_contents->SetSamplerDescriptor(std::move(sampler));

testing/impeller_golden_tests_output.txt

@@ -588,6 +588,9 @@ impeller_Play_AiksTest_DrawAtlasWithColorSimple_Vulkan.png
 impeller_Play_AiksTest_DrawAtlasWithOpacity_Metal.png
 impeller_Play_AiksTest_DrawAtlasWithOpacity_OpenGLES.png
 impeller_Play_AiksTest_DrawAtlasWithOpacity_Vulkan.png
+impeller_Play_AiksTest_DrawImageRectSrcOutsideBounds_Metal.png
+impeller_Play_AiksTest_DrawImageRectSrcOutsideBounds_OpenGLES.png
+impeller_Play_AiksTest_DrawImageRectSrcOutsideBounds_Vulkan.png
 impeller_Play_AiksTest_DrawLinesRenderCorrectly_Metal.png
 impeller_Play_AiksTest_DrawLinesRenderCorrectly_OpenGLES.png
 impeller_Play_AiksTest_DrawLinesRenderCorrectly_Vulkan.png