viz: Fix GLRenderer TextureDrawQuad UV calculation

crrev.com/c/2069137 added support for visible_rect.
Unfortunately it incorrectly computed the UV translation.

It had two issues:
- It was using right() and bottom() instead of width() and height()
 when scaling the UV translation part.
- It was not scaling the translation part for the input UV.

This produced incorrect UVs when a rect was not in the
origin and/or the input UV were scaled.

This patch fixes the computation using
cc::MathUtil::ScaleRectProportional instead.

  in viz_unittests.

Bug: 1059408, 1057953
Test: TextureDrawQuadTranslatedAndVisibleRectInsetTopLeftAndCustomUV
Change-Id: Id852f3c43167364a001f33de07892905c7d3b768
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2149637
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#761038}

components/viz/service/display/gl_renderer.cc

@@ -88,21 +88,14 @@ namespace viz {
 namespace {
 
 Float4 UVTransform(const TextureDrawQuad* quad) {
-  gfx::PointF uv0 = quad->uv_top_left;
-  gfx::PointF uv1 = quad->uv_bottom_right;
-  gfx::PointF translation(
-      quad->visible_rect.origin().x() - quad->rect.origin().x(),
-      quad->visible_rect.origin().y() - quad->rect.origin().y());
-  DCHECK(quad->rect.right() && quad->rect.bottom());
-  translation.Scale(1.f / quad->rect.right(), 1.f / quad->rect.bottom());
-
-  gfx::PointF scale(
-      static_cast<float>(quad->visible_rect.width()) / quad->rect.width(),
-      static_cast<float>(quad->visible_rect.height()) / quad->rect.height());
-
-  Float4 xform = {{translation.x() + uv0.x(), translation.y() + uv0.y(),
-                   (uv1.x() - uv0.x()) * scale.x(),
-                   (uv1.y() - uv0.y()) * scale.y()}};
+  gfx::RectF uv_rect =
+      gfx::BoundingRect(quad->uv_top_left, quad->uv_bottom_right);
+  gfx::RectF visible_uv_rect = cc::MathUtil::ScaleRectProportional(
+      uv_rect, gfx::RectF(quad->rect), gfx::RectF(quad->visible_rect));
+
+  gfx::PointF uv0 = visible_uv_rect.origin();
+  gfx::PointF uv1 = visible_uv_rect.bottom_right();
+  Float4 xform = {{uv0.x(), uv0.y(), uv1.x() - uv0.x(), uv1.y() - uv0.y()}};
   if (quad->y_flipped) {
     xform.data[1] = 1.0f - xform.data[1];
     xform.data[3] = -xform.data[3];

components/viz/service/display/renderer_pixeltest.cc

@@ -1116,6 +1116,50 @@ TYPED_TEST(RendererPixelTest, TextureDrawQuadVisibleRectInsetTopLeft) {
       cc::FuzzyPixelOffByOneComparator(true)));
 }
 
+// This tests drawing a TextureDrawQuad with a visible_rect strictly included in
+// rect, custom UVs, and rect.origin() that is not in the origin.
+TYPED_TEST(RendererPixelTest,
+           TextureDrawQuadTranslatedAndVisibleRectInsetTopLeftAndCustomUV) {
+  gfx::Rect rect(this->device_viewport_size_);
+
+  int id = 1;
+  std::unique_ptr<RenderPass> pass = CreateTestRootRenderPass(id, rect);
+
+  SharedQuadState* texture_quad_state = CreateTestSharedQuadState(
+      gfx::Transform(), rect, pass.get(), gfx::RRectF());
+
+  CreateTestTwoColoredTextureDrawQuad(
+      this->use_gpu(), gfx::Rect(this->device_viewport_size_),
+      SkColorSetARGB(0, 120, 255, 255),  // Texel color 1.
+      SkColorSetARGB(204, 120, 0, 255),  // Texel color 2.
+      SK_ColorGREEN,                     // Background color.
+      true,                              // Premultiplied alpha.
+      false,                             // flipped_texture_quad.
+      false,                             // Half and half.
+      texture_quad_state, this->resource_provider_.get(),
+      this->child_resource_provider_.get(), this->shared_bitmap_manager_.get(),
+      this->child_context_provider_, pass.get());
+  auto* quad = static_cast<TextureDrawQuad*>(pass->quad_list.front());
+  quad->rect.Offset(10, 10);
+  quad->visible_rect.Offset(10, 10);
+  quad->visible_rect.Inset(30, 50, 12, 12);
+  quad->uv_top_left.SetPoint(.2, .3);
+  quad->uv_bottom_right.SetPoint(.4, .7);
+  quad->nearest_neighbor = true;  // To avoid bilinear filter differences.
+  SharedQuadState* color_quad_state = CreateTestSharedQuadState(
+      gfx::Transform(), rect, pass.get(), gfx::RRectF());
+  auto* color_quad = pass->CreateAndAppendDrawQuad<SolidColorDrawQuad>();
+  color_quad->SetNew(color_quad_state, rect, rect, SK_ColorWHITE, false);
+
+  RenderPassList pass_list;
+  pass_list.push_back(std::move(pass));
+
+  EXPECT_TRUE(this->RunPixelTest(
+      &pass_list,
+      base::FilePath(FILE_PATH_LITERAL("offset_inset_top_left.png")),
+      cc::FuzzyPixelOffByOneComparator(true)));
+}
+
 TYPED_TEST(RendererPixelTest, TextureDrawQuadVisibleRectInsetBottomRight) {
   gfx::Rect rect(this->device_viewport_size_);