Title: [148750] trunk/Source/WebCore
- Revision
- 148750
- Author
- [email protected]
- Date
- 2013-04-19 09:17:42 -0700 (Fri, 19 Apr 2013)
Log Message
[Mac] ComplexTextController is slow with large numbers of text runs.
<http://webkit.org/b/114875>
<rdar://problem/13337036>
Reviewed by Dan Bernstein.
Instead of iterating over the text runs in indexOfCurrentRun() to figure out the leftmost glyph,
create a lookup table of [run# -> distance in glyphs] at ComplexTextController construction time.
This avoids O(n^2) behavior in indexOfCurrentRun().
* platform/graphics/mac/ComplexTextController.cpp:
(WebCore::ComplexTextController::ComplexTextController):
(WebCore::ComplexTextController::indexOfCurrentRun):
* platform/graphics/mac/ComplexTextController.h:
(ComplexTextController):
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (148749 => 148750)
--- trunk/Source/WebCore/ChangeLog 2013-04-19 16:03:46 UTC (rev 148749)
+++ trunk/Source/WebCore/ChangeLog 2013-04-19 16:17:42 UTC (rev 148750)
@@ -1,3 +1,22 @@
+2013-04-19 Andreas Kling <[email protected]>
+
+ [Mac] ComplexTextController is slow with large numbers of text runs.
+ <http://webkit.org/b/114875>
+ <rdar://problem/13337036>
+
+ Reviewed by Dan Bernstein.
+
+ Instead of iterating over the text runs in indexOfCurrentRun() to figure out the leftmost glyph,
+ create a lookup table of [run# -> distance in glyphs] at ComplexTextController construction time.
+
+ This avoids O(n^2) behavior in indexOfCurrentRun().
+
+ * platform/graphics/mac/ComplexTextController.cpp:
+ (WebCore::ComplexTextController::ComplexTextController):
+ (WebCore::ComplexTextController::indexOfCurrentRun):
+ * platform/graphics/mac/ComplexTextController.h:
+ (ComplexTextController):
+
2013-04-19 Mario Sanchez Prada <[email protected]>
[GTK] Minimize calls to GailTextUtil in AtkText implementation
Modified: trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.cpp (148749 => 148750)
--- trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.cpp 2013-04-19 16:03:46 UTC (rev 148749)
+++ trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.cpp 2013-04-19 16:17:42 UTC (rev 148750)
@@ -159,9 +159,17 @@
collectComplexTextRuns();
adjustGlyphsAndAdvances();
- if (!m_isLTROnly)
+ if (!m_isLTROnly) {
m_runIndices.reserveInitialCapacity(m_complexTextRuns.size());
+ m_glyphCountFromStartToIndex.reserveInitialCapacity(m_complexTextRuns.size());
+ unsigned glyphCountSoFar = 0;
+ for (unsigned i = 0; i < m_complexTextRuns.size(); ++i) {
+ m_glyphCountFromStartToIndex.uncheckedAppend(glyphCountSoFar);
+ glyphCountSoFar += m_complexTextRuns[i]->glyphCount();
+ }
+ }
+
m_runWidthSoFar = m_leadingExpansion;
}
@@ -448,8 +456,7 @@
}
unsigned currentRunIndex = m_runIndices[m_currentRun];
- for (unsigned i = 0; i < currentRunIndex; ++i)
- leftmostGlyph += m_complexTextRuns[i]->glyphCount();
+ leftmostGlyph = m_glyphCountFromStartToIndex[currentRunIndex];
return currentRunIndex;
}
Modified: trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.h (148749 => 148750)
--- trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.h 2013-04-19 16:03:46 UTC (rev 148749)
+++ trunk/Source/WebCore/platform/graphics/mac/ComplexTextController.h 2013-04-19 16:17:42 UTC (rev 148750)
@@ -132,9 +132,10 @@
unsigned indexOfCurrentRun(unsigned& leftmostGlyph);
unsigned incrementCurrentRun(unsigned& leftmostGlyph);
- // The default size of this vector was selected as being the smallest power of two greater than
+ // The initial capacity of these vectors was selected as being the smallest power of two greater than
// the average (3.5) plus one standard deviation (7.5) of nonzero sizes used on Arabic Wikipedia.
Vector<unsigned, 16> m_runIndices;
+ Vector<unsigned, 16> m_glyphCountFromStartToIndex;
const Font& m_font;
const TextRun& m_run;
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