round out bounds for subpass render target

Author: flar

impeller/entity/entity_pass.cc

@@ -622,6 +622,8 @@ EntityPass::EntityResult EntityPass::GetEntityForElement(
       return EntityPass::EntityResult::Skip();
     }
 
+    subpass_coverage = RoundOut(subpass_coverage.value());
+
     auto subpass_size = ISize(subpass_coverage->size);
     if (subpass_size.IsEmpty()) {
       capture.CreateChild("Subpass Entity (Skipped: Empty subpass coverage B)");

impeller/geometry/geometry_unittests.cc

@@ -2114,6 +2114,17 @@ TEST(GeometryTest, RectProject) {
   }
 }
 
+TEST(GeometryTest, RectRoundOut) {
+  {
+    auto r = Rect::MakeLTRB(-100, -100, 100, 100);
+    ASSERT_EQ(RoundOut(r), r);
+  }
+  {
+    auto r = Rect::MakeLTRB(-100.1, -100.1, 100.1, 100.1);
+    ASSERT_EQ(RoundOut(r), Rect::MakeLTRB(-101, -101, 101, 101));
+  }
+}
+
 TEST(GeometryTest, CubicPathComponentPolylineDoesNotIncludePointOne) {
   CubicPathComponent component({10, 10}, {20, 35}, {35, 20}, {40, 40});
   auto polyline = component.CreatePolyline(1.0f);

impeller/geometry/rect.h

@@ -315,6 +315,11 @@ struct TRect {
 using Rect = TRect<Scalar>;
 using IRect = TRect<int64_t>;
 
+constexpr inline Rect RoundOut(const Rect& r) {
+  return Rect::MakeLTRB(floor(r.GetLeft()), floor(r.GetTop()),
+                        ceil(r.GetRight()), ceil(r.GetBottom()));
+}
+
 constexpr inline std::optional<Rect> Union(const Rect& a,
                                            const std::optional<Rect> b) {
   return b.has_value() ? a.Union(b.value()) : a;