From 818ca06d715a25417635610e6aaa93029f6cc078 Mon Sep 17 00:00:00 2001
From: Brandon DeRosier <bdero@google.com>
Date: Wed, 12 Apr 2023 10:55:16 -0700
Subject: [PATCH] [Impeller] Improve accuracy of glyph spacing
 (flutter/engine#41101)

---
 .../src/flutter/impeller/aiks/aiks_unittests.cc | 17 ++++++++++-------
 .../backends/skia/text_frame_skia.cc            |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/engine/src/flutter/impeller/aiks/aiks_unittests.cc b/engine/src/flutter/impeller/aiks/aiks_unittests.cc
index 0211b27797..f43021f6b9 100644
--- a/engine/src/flutter/impeller/aiks/aiks_unittests.cc
+++ b/engine/src/flutter/impeller/aiks/aiks_unittests.cc
@@ -1068,6 +1068,7 @@ bool RenderTextInCanvas(const std::shared_ptr<Context>& context,
 
 TEST_P(AiksTest, CanRenderTextFrame) {
   Canvas canvas;
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
   ASSERT_TRUE(RenderTextInCanvas(
       GetContext(), canvas, "the quick brown fox jumped over the lazy dog!.?",
       "Roboto-Regular.ttf"));
@@ -1119,6 +1120,8 @@ TEST_P(AiksTest, TextFrameSubpixelAlignment) {
 
 TEST_P(AiksTest, CanRenderItalicizedText) {
   Canvas canvas;
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
+
   ASSERT_TRUE(RenderTextInCanvas(
       GetContext(), canvas, "the quick brown fox jumped over the lazy dog!.?",
       "HomemadeApple.ttf"));
@@ -1127,6 +1130,8 @@ TEST_P(AiksTest, CanRenderItalicizedText) {
 
 TEST_P(AiksTest, CanRenderEmojiTextFrame) {
   Canvas canvas;
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
+
   ASSERT_TRUE(RenderTextInCanvas(GetContext(), canvas,
                                  "😀 😃 😄 😁 😆 😅 😂 🤣 🥲 😊",
 #if FML_OS_MACOSX
@@ -1139,6 +1144,8 @@ TEST_P(AiksTest, CanRenderEmojiTextFrame) {
 
 TEST_P(AiksTest, CanRenderEmojiTextFrameWithAlpha) {
   Canvas canvas;
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
+
   ASSERT_TRUE(RenderTextInCanvas(GetContext(), canvas,
                                  "😀 😃 😄 😁 😆 😅 😂 🤣 🥲 😊",
 #if FML_OS_MACOSX
@@ -1152,7 +1159,8 @@ TEST_P(AiksTest, CanRenderEmojiTextFrameWithAlpha) {
 
 TEST_P(AiksTest, CanRenderTextInSaveLayer) {
   Canvas canvas;
-  canvas.DrawPaint({.color = Color::White()});
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
+
   canvas.Translate({100, 100});
   canvas.Scale(Vector2{0.5, 0.5});
 
@@ -1211,12 +1219,7 @@ TEST_P(AiksTest, CanRenderTextOutsideBoundaries) {
 TEST_P(AiksTest, TextRotated) {
   Canvas canvas;
   canvas.Scale(GetContentScale());
-
-  Paint paint;
-  paint.color = Color(0.1, 0.1, 0.1, 1.0);
-  canvas.DrawRect(
-      Rect::MakeLTRB(0, 0, GetWindowSize().width, GetWindowSize().height),
-      paint);
+  canvas.DrawPaint({.color = Color(0.1, 0.1, 0.1, 1.0)});
 
   canvas.Transform(Matrix(0.25, -0.3, 0, -0.002,  //
                           0, 0.5, 0, 0,           //
diff --git a/engine/src/flutter/impeller/typographer/backends/skia/text_frame_skia.cc b/engine/src/flutter/impeller/typographer/backends/skia/text_frame_skia.cc
index 1e2957cd48..534bab00bd 100644
--- a/engine/src/flutter/impeller/typographer/backends/skia/text_frame_skia.cc
+++ b/engine/src/flutter/impeller/typographer/backends/skia/text_frame_skia.cc
@@ -76,7 +76,7 @@ TextFrame TextFrameFromTextBlob(const sk_sp<SkTextBlob>& blob, Scalar scale) {
                                  : Glyph::Type::kPath;
 
           text_run.AddGlyph(Glyph{glyphs[i], type, ToRect(glyph_bounds[i])},
-                            Point{point->x(), point->y()}.Floor());
+                            Point{point->x(), point->y()}.Round());
         }
         break;
       }