Always use original ascent/descent for FontMetrics::floatAscent|floatDescent

third_party/WebKit/Source/platform/fonts/SimpleFontData.cpp

 /*
  * Copyright (C) 2005, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 39 matching lines @@
 const float smallCapsFontSizeMultiplier = 0.7f;
 const float emphasisMarkFontSizeMultiplier = 0.5f;
 
 #if OS(LINUX) || OS(ANDROID)
 // This is the largest VDMX table which we'll try to load and parse.
 static const size_t maxVDMXTableSize = 1024 * 1024;  // 1 MB
 #endif
 
 SimpleFontData::SimpleFontData(const FontPlatformData& platformData,
                                PassRefPtr<CustomFontData> customData,
-                               bool isTextOrientationFallback,
-                               bool subpixelAscentDescent)
+                               bool isTextOrientationFallback)
     : m_maxCharWidth(-1),
       m_avgCharWidth(-1),
       m_platformData(platformData),
       m_isTextOrientationFallback(isTextOrientationFallback),
       m_verticalData(nullptr),
       m_hasVerticalGlyphs(false),
       m_customFontData(std::move(customData)) {
-  platformInit(subpixelAscentDescent);
+  platformInit();
   platformGlyphInit();
   if (platformData.isVerticalAnyUpright() && !isTextOrientationFallback) {
     m_verticalData = platformData.verticalData();
     m_hasVerticalGlyphs =
         m_verticalData.get() && m_verticalData->hasVerticalMetrics();
   }
 }
 
 SimpleFontData::SimpleFontData(const FontPlatformData& platformData,
                                PassRefPtr<OpenTypeVerticalData> verticalData)
     : m_platformData(platformData),
       m_isTextOrientationFallback(false),
       m_verticalData(verticalData),
       m_hasVerticalGlyphs(false) {}
 
-void SimpleFontData::platformInit(bool subpixelAscentDescent) {
+void SimpleFontData::platformInit() {
   if (!m_platformData.size()) {
     m_fontMetrics.reset();
     m_avgCharWidth = 0;
     m_maxCharWidth = 0;
     return;
   }
 
   SkPaint::FontMetrics metrics;
 
   m_platformData.setupPaint(&m_paint);
@@ skipping 30 matching lines @@
   float ascent;
   float descent;
 
   // Beware those who step here: This code is designed to match Win32 font
   // metrics *exactly* except:
   // - the adjustment of ascent/descent on Linux/Android
   // - metrics.fAscent and .fDesscent are not rounded to int for tiny fonts
   if (isVDMXValid) {
     ascent = vdmxAscent;
     descent = -vdmxDescent;
-  } else if (subpixelAscentDescent &&
-             (-metrics.fAscent < 3 ||
-              -metrics.fAscent + metrics.fDescent < 2)) {
-    // For tiny fonts, the rounding of fAscent and fDescent results in equal
-    // baseline for different types of text baselines (crbug.com/338908).
-    // Please see CanvasRenderingContext2D::getFontBaseline for the heuristic.
+  } else {
     ascent = -metrics.fAscent;
     descent = metrics.fDescent;
-  } else {
-    ascent = SkScalarRoundToScalar(-metrics.fAscent);
-    descent = SkScalarRoundToScalar(metrics.fDescent);
-
-    int overflowInflationForAscent = ascent < -metrics.fAscent ? 1 : 0;
-    int overflowInflationForDescent = descent < metrics.fDescent ? 1 : 0;
-    if (overflowInflationForDescent) {
-#if OS(LINUX) || OS(ANDROID)
-      // When subpixel positioning is enabled, if the descent is rounded down,
-      // the descent part of the glyph may be truncated when displayed in a
-      // 'overflow: hidden' container.  To avoid that, borrow 1 unit from the
-      // ascent when possible.
-      if (platformData().getFontRenderStyle().useSubpixelPositioning &&
-          ascent >= 1) {
-        ++descent;
-        --ascent;
-        // We should inflate overflow 1 more pixel for ascent instead.
-        overflowInflationForDescent = 0;
-        ++overflowInflationForAscent;
-      }
-#endif
-    }
-    m_fontMetrics.setVisualOverflowInflations(overflowInflationForAscent,
-                                              overflowInflationForDescent);
   }
 
 #if OS(MACOSX)
   // We are preserving this ascent hack to match Safari's ascent adjustment
   // in their SimpleFontDataMac.mm, for details see crbug.com/445830.
   // We need to adjust Times, Helvetica, and Courier to closely match the
   // vertical metrics of their Microsoft counterparts that are the de facto
   // web standard. The AppKit adjustment of 20% is too big and is
   // incorrectly added to line spacing, so we use a 15% adjustment instead
   // and add it to the ascent.
@@ skipping 211 matching lines @@
 float SimpleFontData::platformWidthForGlyph(Glyph glyph) const {
   if (!m_platformData.size())
     return 0;
 
   static_assert(sizeof(glyph) == 2, "Glyph id should not be truncated.");
 
   return SkiaTextMetrics(&m_paint).getSkiaWidthForGlyph(glyph);
 }
 
 }  // namespace blink