Changeset 154674 in webkit

Timestamp:

Aug 27, 2013 3:22:20 AM (11 years ago)

Author:

allan.jensen@digia.com

Message:

Font's fast code path doesn't handle partial runs correctly when kerning or ligatures are enabled
​https://bugs.webkit.org/show_bug.cgi?id=100050

Reviewed by Darin Adler.

Renamed m_characterIndex to m_characterIndexOfGlyph and gave it an inline size of 10,
which covers around 66% of all cases. The rest of the cases are now preallocated to the
upper limit which is length of the original TextRun.

• platform/graphics/FontFastPath.cpp:

(WebCore::Font::getGlyphsAndAdvancesForSimpleText):
(WebCore::Font::selectionRectForSimpleText):
(WebCore::Font::offsetForPositionForSimpleText):

• platform/graphics/WidthIterator.cpp:

(WebCore::WidthIterator::WidthIterator):
(WebCore::WidthIterator::advanceInternal):

• platform/graphics/WidthIterator.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/FontFastPath.cpp (modified) (6 diffs)
• platform/graphics/WidthIterator.cpp (modified) (3 diffs)
• platform/graphics/WidthIterator.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-08-27  Allan Sandfeld Jensen  <allan.jensen@digia.com>
+
+        Font's fast code path doesn't handle partial runs correctly when kerning or ligatures are enabled
+        https://bugs.webkit.org/show_bug.cgi?id=100050
+
+        Reviewed by Darin Adler.
+
+        Renamed m_characterIndex to m_characterIndexOfGlyph and gave it an inline size of 10,
+        which covers around 66% of all cases. The rest of the cases are now preallocated to the
+        upper limit which is length of the original TextRun.
+
+        * platform/graphics/FontFastPath.cpp:
+        (WebCore::Font::getGlyphsAndAdvancesForSimpleText):
+        (WebCore::Font::selectionRectForSimpleText):
+        (WebCore::Font::offsetForPositionForSimpleText):
+        * platform/graphics/WidthIterator.cpp:
+        (WebCore::WidthIterator::WidthIterator):
+        (WebCore::WidthIterator::advanceInternal):
+        * platform/graphics/WidthIterator.h:
+
 2013-08-27  Christophe Dumez  <ch.dumez@sisa.samsung.com>
 

trunk/Source/WebCore/platform/graphics/FontFastPath.cpp

@@ -140 +140 @@
     float beforeWidth = 0;
     int glyphPos = 0;
-    for (; glyphPos < localGlyphBuffer.size() && it.m_characterIndex[glyphPos] < from; ++glyphPos)
+    for (; glyphPos < localGlyphBuffer.size() && it.m_characterIndexOfGlyph[glyphPos] < from; ++glyphPos)
         beforeWidth += localGlyphBuffer.advanceAt(glyphPos).width();
     int glyphFrom = glyphPos;
@@ -146 +146 @@
     float afterWidth = totalWidth;
     glyphPos = localGlyphBuffer.size() - 1;
-    for (; glyphPos >= glyphFrom && it.m_characterIndex[glyphPos] >= to; --glyphPos)
+    for (; glyphPos >= glyphFrom && it.m_characterIndexOfGlyph[glyphPos] >= to; --glyphPos)
         afterWidth -= localGlyphBuffer.advanceAt(glyphPos).width();
     int glyphTo = glyphPos + 1;
@@ -304 +304 @@
     float beforeWidth = 0;
     int glyphPos = 0;
-    for (; glyphPos < glyphBuffer.size() && it.m_characterIndex[glyphPos] < from; ++glyphPos)
+    for (; glyphPos < glyphBuffer.size() && it.m_characterIndexOfGlyph[glyphPos] < from; ++glyphPos)
         beforeWidth += glyphBuffer.advanceAt(glyphPos).width();
     int glyphFrom = glyphPos;
@@ -310 +310 @@
     float afterWidth = totalWidth;
     glyphPos = glyphBuffer.size() - 1;
-    for (; glyphPos >= glyphFrom && it.m_characterIndex[glyphPos] >= to; --glyphPos)
+    for (; glyphPos >= glyphFrom && it.m_characterIndexOfGlyph[glyphPos] >= to; --glyphPos)
         afterWidth -= glyphBuffer.advanceAt(glyphPos).width();
 
@@ -335 +335 @@
                 break;
             }
-            characterOffset = it.m_characterIndex[glyphPosition];
+            characterOffset = it.m_characterIndexOfGlyph[glyphPosition];
             float glyphWidth = glyphBuffer.advanceAt(glyphPosition).width();
             if (includePartialGlyphs) {
@@ -353 +353 @@
                 break;
             }
-            characterOffset = it.m_characterIndex[glyphPosition];
+            characterOffset = it.m_characterIndexOfGlyph[glyphPosition];
             float glyphWidth = glyphBuffer.advanceAt(glyphPosition).width();
             if (includePartialGlyphs) {

trunk/Source/WebCore/platform/graphics/WidthIterator.cpp

@@ -68 +68 @@
             m_expansionPerOpportunity = m_expansion / expansionOpportunityCount;
     }
+    // Character-index will end up the same or slightly shorter than m_run, so if we reserve that much it will never need to resize.
+    m_characterIndexOfGlyph.reserveInitialCapacity(m_run.length());
 }
 
@@ -232 +234 @@
                                 else
                                     glyphBuffer->add(fontData->spaceGlyph(), fontData, expansionAtThisOpportunity);
-                                m_characterIndex.append(currentCharacterIndex);
+                                m_characterIndexOfGlyph.append(currentCharacterIndex);
                             } else
                                 glyphBuffer->expandLastAdvance(expansionAtThisOpportunity);
@@ -301 +303 @@
         if (glyphBuffer) {
             glyphBuffer->add(glyph, fontData, (rtl ? oldWidth + lastRoundingWidth : width));
-            m_characterIndex.append(currentCharacterIndex);
+            m_characterIndexOfGlyph.append(currentCharacterIndex);
         }
 

trunk/Source/WebCore/platform/graphics/WidthIterator.h

@@ -83 +83 @@
     bool m_isAfterExpansion;
     float m_finalRoundingWidth;
-    Vector<int> m_characterIndex;
+    // An inline capacity of 10 catches around 2/3 of the cases. To catch 90% we would need 32.
+    Vector<int, 10> m_characterIndexOfGlyph;
 
 #if ENABLE(SVG_FONTS)