Changeset 58467 in webkit

Timestamp:

Apr 28, 2010, 8:11:37 PM (15 years ago)

Author:

mitz@apple.com

Message:

More of <rdar://problem/7855777> REGRESSION: Memory usage increase caused by storing glyph bounds in GlyphMetricsMap
​https://bugs.webkit.org/show_bug.cgi?id=37936

Reviewed by Adele Peterson.

Assigning zero width and empty bounds to the ZERO WIDTH SPACE glyph often allocates a width map
page and a bounds map page for the glyph, each of which pages contains 255 unused entries. Save
this space by not storing the zero width and empty bounds in the metrics maps.

• platform/graphics/SimpleFontData.cpp:

(WebCore::SimpleFontData::SimpleFontData): Initialize m_zeroWidthSpaceGlyph.
(WebCore::SimpleFontData::platformGlyphInit): Set m_zeroWidthSpaceGlyph. Don’t create entries
for the ZERO WIDTH SPACE glyph in the width map and in the bounds map.

• platform/graphics/SimpleFontData.h:

(WebCore::SimpleFontData::boundsForGlyph): Return empty bounds for the ZERO WIDTH SPACE glyph
without consulting the bounds map.
(WebCore::SimpleFontData::widthForGlyph): Return zero for the ZERO WIDTH SPACE glyph without
consulting the width map.

Location:

trunk/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/SimpleFontData.cpp (modified) (3 diffs)
• platform/graphics/SimpleFontData.h (modified) (3 diffs)

trunk/WebCore/ChangeLog

@@ +1 @@
+2010-04-28  Dan Bernstein  <mitz@apple.com>
+
+        Reviewed by Adele Peterson.
+
+        More of <rdar://problem/7855777> REGRESSION: Memory usage increase caused by storing glyph bounds in GlyphMetricsMap
+        https://bugs.webkit.org/show_bug.cgi?id=37936
+
+        Assigning zero width and empty bounds to the ZERO WIDTH SPACE glyph often allocates a width map
+        page and a bounds map page for the glyph, each of which pages contains 255 unused entries. Save
+        this space by not storing the zero width and empty bounds in the metrics maps.
+
+        * platform/graphics/SimpleFontData.cpp:
+        (WebCore::SimpleFontData::SimpleFontData): Initialize m_zeroWidthSpaceGlyph.
+        (WebCore::SimpleFontData::platformGlyphInit): Set m_zeroWidthSpaceGlyph. Don’t create entries
+        for the ZERO WIDTH SPACE glyph in the width map and in the bounds map.
+        * platform/graphics/SimpleFontData.h:
+        (WebCore::SimpleFontData::boundsForGlyph): Return empty bounds for the ZERO WIDTH SPACE glyph
+        without consulting the bounds map.
+        (WebCore::SimpleFontData::widthForGlyph): Return zero for the ZERO WIDTH SPACE glyph without
+        consulting the width map.
+
 2010-04-28  Mark Rowe  <mrowe@apple.com>
 

trunk/WebCore/platform/graphics/SimpleFontData.cpp

@@ -93 +93 @@
         // FIXME: is there a way we can get the space glyph from the SVGGlyphIdentifier above?
         m_spaceGlyph = 0;
+        m_zeroWidthSpaceGlyph = 0;
         determinePitch();
         m_adjustedSpaceWidth = roundf(m_spaceWidth);
@@ -137 +138 @@
         m_adjustedSpaceWidth = 0;
         determinePitch();
+        m_zeroWidthSpaceGlyph = 0;
         m_missingGlyphData.fontData = this;
         m_missingGlyphData.glyph = 0;
@@ -156 +158 @@
     // Ask for the glyph for 0 to avoid paging in ZERO WIDTH SPACE. Control characters, including 0,
     // are mapped to the ZERO WIDTH SPACE glyph.
-    Glyph zeroWidthSpaceGlyph = glyphPageZero->glyphDataForCharacter(0).glyph;
-    if (zeroWidthSpaceGlyph) {
-        if (zeroWidthSpaceGlyph != m_spaceGlyph) {
-            m_glyphToWidthMap.setMetricsForGlyph(zeroWidthSpaceGlyph, 0);
-            m_glyphToBoundsMap.setMetricsForGlyph(zeroWidthSpaceGlyph, FloatRect());
-        } else
-            LOG_ERROR("Font maps SPACE and ZERO WIDTH SPACE to the same glyph. Glyph width not overridden.");
+    m_zeroWidthSpaceGlyph = glyphPageZero->glyphDataForCharacter(0).glyph;
+    if (m_zeroWidthSpaceGlyph == m_spaceGlyph) {
+        m_zeroWidthSpaceGlyph = 0;
+        LOG_ERROR("Font maps SPACE and ZERO WIDTH SPACE to the same glyph. Glyph width will not be overridden.");
     }
 

trunk/WebCore/platform/graphics/SimpleFontData.h

@@ -201 +201 @@
     float m_adjustedSpaceWidth;
 
+    Glyph m_zeroWidthSpaceGlyph;
+
     GlyphData m_missingGlyphData;
 
@@ -244 +246 @@
 ALWAYS_INLINE FloatRect SimpleFontData::boundsForGlyph(Glyph glyph) const
 {
+    if (glyph == m_zeroWidthSpaceGlyph && glyph)
+        return FloatRect();
+
     FloatRect bounds = m_glyphToBoundsMap.metricsForGlyph(glyph);
     if (bounds.width() != cGlyphSizeUnknown)
         return bounds;
+
     bounds = platformBoundsForGlyph(glyph);
     m_glyphToBoundsMap.setMetricsForGlyph(glyph, bounds);
@@ -254 +260 @@
 ALWAYS_INLINE float SimpleFontData::widthForGlyph(Glyph glyph) const
 {
+    if (glyph == m_zeroWidthSpaceGlyph && glyph)
+        return 0;
+
     float width = m_glyphToWidthMap.metricsForGlyph(glyph);
     if (width != cGlyphSizeUnknown)