cip/WikiOnBoard — Issue #72: Article page scrolling performance on harmattan
Author: cip
Created: 2012-01-05 17:25:06+00:00
State: open

Scrolling of article page on harmattan is significantly slower than on symbian^3, i.p. if article contains (a lot of?) images.
See also releated thread http://www.developer.nokia.com/Community/Discussion/showthread.php?228740-QPainter-performance-in-Harmattan

Interestingly setting QApplication::setGraphicsSystem(QLatin1String("raster")); in main improves performance significantly.
Not clear whether this has side-effects. (Note that using "opengl" and "meego" (should be default) apperantly do not improve performance)
Note that setting any of "opengl" "meego" or "raster" has the sideeffect that if app started by qt creator the toolbar is not displayed.
If started on phone, works as expected. Wtihout setGraphicsSystem line works as expected also if started by Qt-Creator. (Strange, as actually meego should be default).

Note that according to https://bugreports.qt.nokia.com//browse/QTBUG-20734 there is a performance problem with large (>2000px) pixmaps. However this does not seem to be the cause here, as at least in test article (en-Wikipedia 0.8, "graz") images are smaller.

=> Use "raster" renderer. However, reconsider before relaease using default renderer. (i.p. check whether fw-update available for N950)