From faa5bea1b96ddb3ca9eb69a7dc88edabb01884b4 Mon Sep 17 00:00:00 2001
From: Brandon DeRosier <bdero@google.com>
Date: Tue, 6 Sep 2022 23:57:31 -0700
Subject: [PATCH] [Impeller] Use ascent/descent rather than deprecated
 top/bottom for glyph bounds (flutter/engine#35960)

---
 .../impeller/entity/contents/text_contents.cc |  4 ++-
 .../backends/skia/text_frame_skia.cc          |  4 +--
 .../backends/skia/text_render_context_skia.cc | 25 +++++++++++--------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/engine/src/flutter/impeller/entity/contents/text_contents.cc b/engine/src/flutter/impeller/entity/contents/text_contents.cc
index c082aabb4a1..3768dc05efe 100644
--- a/engine/src/flutter/impeller/entity/contents/text_contents.cc
+++ b/engine/src/flutter/impeller/entity/contents/text_contents.cc
@@ -138,7 +138,9 @@ bool TextContents::Render(const ContentContext& renderer,
             Point{font.GetMetrics().min_extent.x, font.GetMetrics().ascent};
         vtx.glyph_size = Point{static_cast<Scalar>(glyph_size.width),
                                static_cast<Scalar>(glyph_size.height)};
-        vtx.atlas_position = atlas_glyph_pos->origin;
+        vtx.atlas_position =
+            atlas_glyph_pos->origin + Point{1 / atlas_glyph_pos->size.width,
+                                            1 / atlas_glyph_pos->size.height};
         vtx.atlas_glyph_size =
             Point{atlas_glyph_pos->size.width, atlas_glyph_pos->size.height};
         vertex_builder.AppendVertex(std::move(vtx));
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 fa3e7406844..287876de3a7 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
@@ -23,8 +23,8 @@ static Font ToFont(const SkFont& font, Scalar scale) {
   metrics.point_size = font.getSize();
   metrics.ascent = sk_metrics.fAscent;
   metrics.descent = sk_metrics.fDescent;
-  metrics.min_extent = {sk_metrics.fXMin, sk_metrics.fTop};
-  metrics.max_extent = {sk_metrics.fXMax, sk_metrics.fBottom};
+  metrics.min_extent = {sk_metrics.fXMin, sk_metrics.fAscent};
+  metrics.max_extent = {sk_metrics.fXMax, sk_metrics.fDescent};
 
   return Font{std::move(typeface), std::move(metrics)};
 }
diff --git a/engine/src/flutter/impeller/typographer/backends/skia/text_render_context_skia.cc b/engine/src/flutter/impeller/typographer/backends/skia/text_render_context_skia.cc
index cb6fbec001c..aab49ed2fec 100644
--- a/engine/src/flutter/impeller/typographer/backends/skia/text_render_context_skia.cc
+++ b/engine/src/flutter/impeller/typographer/backends/skia/text_render_context_skia.cc
@@ -122,13 +122,14 @@ static std::shared_ptr<SkBitmap> CreateAtlasBitmap(const GlyphAtlas& atlas,
 
   atlas.IterateGlyphs([canvas](const FontGlyphPair& font_glyph,
                                const Rect& location) -> bool {
-    const auto position = SkPoint::Make(location.origin.x, location.origin.y);
+    const auto position =
+        SkPoint::Make(location.origin.x / font_glyph.font.GetMetrics().scale,
+                      location.origin.y / font_glyph.font.GetMetrics().scale);
     SkGlyphID glyph_id = font_glyph.glyph.index;
 
     SkFont sk_font(
         TypefaceSkia::Cast(*font_glyph.font.GetTypeface()).GetSkiaTypeface(),
-        font_glyph.font.GetMetrics().point_size *
-            font_glyph.font.GetMetrics().scale);
+        font_glyph.font.GetMetrics().point_size);
 
     const auto& metrics = font_glyph.font.GetMetrics();
 
@@ -136,14 +137,16 @@ static std::shared_ptr<SkBitmap> CreateAtlasBitmap(const GlyphAtlas& atlas,
 
     SkPaint glyph_paint;
     glyph_paint.setColor(glyph_color);
-    canvas->drawGlyphs(
-        1u,         // count
-        &glyph_id,  // glyphs
-        &position,  // positions
-        SkPoint::Make(-metrics.min_extent.x * metrics.scale,
-                      -metrics.ascent * metrics.scale),  // origin
-        sk_font,                                         // font
-        glyph_paint                                      // paint
+    canvas->resetMatrix();
+    canvas->scale(font_glyph.font.GetMetrics().scale,
+                  font_glyph.font.GetMetrics().scale);
+    canvas->drawGlyphs(1u,         // count
+                       &glyph_id,  // glyphs
+                       &position,  // positions
+                       SkPoint::Make(-metrics.min_extent.x,
+                                     -metrics.ascent),  // origin
+                       sk_font,                         // font
+                       glyph_paint                      // paint
     );
     return true;
   });