Details
Description
Drawing a lot of lines (for example a triangular wave with short wave length) with stroke() on html 5 canvas takes really long time in Qt5 compared to Qt4.8.x. The problem can be reproduced with the attached html/javascript file (testijs.html) in Qt's Fancy Browser example. Just open the file and wait until it is rendered. In Qt 4.8.x it takes a couple of seconds and in Qt5 it takes around 30 seconds on Windows 7.
I also ran the javascript through the http://jsperf.com/ performance test and it gave the following results (on Windows 7):
FancyBrowser Qt5.1.0: 1.68 operations/sec
FancyBrowser Qt4.8.5: 8.08 operations/sec
Chrome(for reference): 12.60 operations/sec
This has been tested in Qt 5.0, 5.1.1, 5.2 with or without OpenGL support, in release and in debug builds, and on Windows, Linux and Mac.
Attachments
For Gerrit Dashboard: QTBUG-34855 | ||||||
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# | Subject | Branch | Project | Status | CR | V |
71695,2 | Fix performance regression in HTML5 canvas stroke() | release | qt/qtwebkit | Status: ABANDONED | 0 | 0 |
71697,1 | Fix performance regression in HTML5 canvas stroke() | stable | qt/qtwebkit | Status: MERGED | +2 | 0 |