[Impeller] Fix the transform and geometry criteria for an optimization in TiledTextureContents (flutter/engine#47341)

TiledTextureContents::RenderToSnapshot should only create a snapshot directly from the texture if the geometry is an axis-aligned rectangle.

Fixes https://github.com/flutter/flutter/issues/136504

engine/src/flutter/impeller/aiks/aiks_unittests.cc

@@ -3781,5 +3781,55 @@ TEST_P(AiksTest, EmptySaveLayerRendersWithClear) {
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 
+TEST_P(AiksTest, BlurredRectangleWithShader) {
+  Canvas canvas;
+  canvas.Scale(GetContentScale());
+
+  auto paint_lines = [&canvas](Scalar dx, Scalar dy, Paint paint) {
+    auto draw_line = [&canvas, &paint](Point a, Point b) {
+      canvas.DrawPath(PathBuilder{}.AddLine(a, b).TakePath(), paint);
+    };
+    paint.stroke_width = 5;
+    paint.style = Paint::Style::kStroke;
+    draw_line(Point(dx + 100, dy + 100), Point(dx + 200, dy + 200));
+    draw_line(Point(dx + 100, dy + 200), Point(dx + 200, dy + 100));
+    draw_line(Point(dx + 150, dy + 100), Point(dx + 200, dy + 150));
+    draw_line(Point(dx + 100, dy + 150), Point(dx + 150, dy + 200));
+  };
+
+  AiksContext renderer(GetContext(), nullptr);
+  Canvas recorder_canvas;
+  for (int x = 0; x < 5; ++x) {
+    for (int y = 0; y < 5; ++y) {
+      Rect rect = Rect::MakeXYWH(x * 20, y * 20, 20, 20);
+      Paint paint{.color =
+                      ((x + y) & 1) == 0 ? Color::Yellow() : Color::Blue()};
+      recorder_canvas.DrawRect(rect, paint);
+    }
+  }
+  Picture picture = recorder_canvas.EndRecordingAsPicture();
+  std::shared_ptr<Texture> texture =
+      picture.ToImage(renderer, ISize{100, 100})->GetTexture();
+
+  ColorSource image_source = ColorSource::MakeImage(
+      texture, Entity::TileMode::kRepeat, Entity::TileMode::kRepeat, {}, {});
+  std::shared_ptr<ImageFilter> blur_filter = ImageFilter::MakeBlur(
+      Sigma(5), Sigma(5), FilterContents::BlurStyle::kNormal,
+      Entity::TileMode::kDecal);
+  canvas.DrawRect(Rect::MakeLTRB(0, 0, 300, 600),
+                  Paint{.color = Color::DarkGreen()});
+  canvas.DrawRect(Rect::MakeLTRB(100, 100, 200, 200),
+                  Paint{.color_source = image_source});
+  canvas.DrawRect(Rect::MakeLTRB(300, 0, 600, 600),
+                  Paint{.color = Color::Red()});
+  canvas.DrawRect(
+      Rect::MakeLTRB(400, 100, 500, 200),
+      Paint{.color_source = image_source, .image_filter = blur_filter});
+  paint_lines(0, 300, Paint{.color_source = image_source});
+  paint_lines(300, 300,
+              Paint{.color_source = image_source, .image_filter = blur_filter});
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
 }  // namespace testing
 }  // namespace impeller

engine/src/flutter/impeller/entity/contents/tiled_texture_contents.cc

@@ -202,10 +202,18 @@ std::optional<Snapshot> TiledTextureContents::RenderToSnapshot(
     const std::optional<SamplerDescriptor>& sampler_descriptor,
     bool msaa_enabled,
     const std::string& label) const {
-  if (GetInverseEffectTransform().IsIdentity()) {
+  if (GetInverseEffectTransform().IsIdentity() &&
+      GetGeometry()->IsAxisAlignedRect()) {
+    auto coverage = GetCoverage(entity);
+    if (!coverage.has_value()) {
+      return std::nullopt;
+    }
+    auto scale = Vector2(coverage->size / Size(texture_->GetSize()));
+
     return Snapshot{
         .texture = texture_,
-        .transform = entity.GetTransformation(),
+        .transform = Matrix::MakeTranslation(coverage->origin) *
+                     Matrix::MakeScale(scale),
         .sampler_descriptor = sampler_descriptor.value_or(sampler_descriptor_),
         .opacity = GetOpacityFactor(),
     };

engine/src/flutter/impeller/entity/geometry/geometry.cc

@@ -147,4 +147,8 @@ bool Geometry::CoversArea(const Matrix& transform, const Rect& rect) const {
   return false;
 }
 
+bool Geometry::IsAxisAlignedRect() const {
+  return false;
+}
+
 }  // namespace impeller

engine/src/flutter/impeller/entity/geometry/geometry.h

@@ -101,6 +101,8 @@ class Geometry {
   ///           given `rect`. May return `false` in many undetected cases where
   ///           the transformed geometry does in fact cover the `rect`.
   virtual bool CoversArea(const Matrix& transform, const Rect& rect) const;
+
+  virtual bool IsAxisAlignedRect() const;
 };
 
 }  // namespace impeller

engine/src/flutter/impeller/entity/geometry/rect_geometry.cc

@@ -55,4 +55,8 @@ bool RectGeometry::CoversArea(const Matrix& transform, const Rect& rect) const {
   return coverage.Contains(rect);
 }
 
+bool RectGeometry::IsAxisAlignedRect() const {
+  return true;
+}
+
 }  // namespace impeller

engine/src/flutter/impeller/entity/geometry/rect_geometry.h

@@ -17,6 +17,9 @@ class RectGeometry : public Geometry {
   // |Geometry|
   bool CoversArea(const Matrix& transform, const Rect& rect) const override;
 
+  // |Geometry|
+  bool IsAxisAlignedRect() const override;
+
  private:
   // |Geometry|
   GeometryResult GetPositionBuffer(const ContentContext& renderer,