[CSS Shapes] Improve the performance of image valued shapes with large shape-margins
https://bugs.webkit.org/show_bug.cgi?id=122613
Reviewed by Andreas Kling.
The cost of computing the shape-margin boundary of an image-valued shape-outside
is now proportional to (2 * shape-margin + image.height) rather than
(2 * shape-margin * image.height). The performance improvement comes from skipping
sequences of rounded-rectangle intervals that will not contribute to the final
result. Each non-empty row in the original image contributes one rounded-rectangle
whose corner radius is shape-margin, height is 2 * shape-margin, and width is
2 * shape-margin plus the width of the limits of the intervals on the row.
Renamed private method RasterShape::getIntervals() to intervalsAt() to be a little
more consistent with WebKit naming conventions.
There are no new tests since is just an internal refactoring.
* rendering/shapes/RasterShape.cpp:
(WebCore::MarginIntervalGenerator::set): Changed the x1,x2 parameters to an IntShapeInterval.
(WebCore::RasterShapeIntervals::contains): Refactor for the getIntervals() => intervalsAt() rename.
(WebCore::RasterShapeIntervals::getIntervalX1Values): Ditto.
(WebCore::RasterShapeIntervals::getIncludedIntervals): Ditto.
(WebCore::RasterShapeIntervals::getExcludedIntervals): Ditto.
(WebCore::RasterShapeIntervals::computeShapeMarginIntervals): Performance tuning.
* rendering/shapes/RasterShape.h:
(WebCore::RasterShapeIntervals::intervalsAt): Renamed getIntervals().
(WebCore::RasterShapeIntervals::limitIntervalAt): Return the min/max limits of the intervals at Y.
* rendering/shapes/ShapeInterval.h:
(WebCore::ShapeInterval::isEmpty): Added.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157574 268f45cc-cd09-0410-ab3c-d52691b4dbfc
4 files changed
