29438 2009-09-18 07:48:34 -0700 [Qt] NPAPI: HBITMAP to QPixmap conversion is slow 2014-01-28 20:30:06 -0800 1 1 1 Unclassified WebKit Plug-ins 528+ (Nightly build) Other Windows XP RESOLVED INVALID Performance, Qt, QtTriaged P2 Normal --- 35962 1 vestbo webkit-unassigned andersca davidtlwong kenneth tonikitoo oldest_to_newest 148144 0 vestbo 2009-09-18 07:48:34 -0700 banner uses more CPU time than normal browser. This bug report originated from issue QTBUG-4251 <http://bugreports.qt.nokia.com/browse/QTBUG-4251> --- Description --- Simple test application (source attached) shows webpage with flash banner. Unfortunately it uses much more CPU time than normal browser which shows same page (Internet Explorer, Mozilla Firefox, Safari). We analysed application using DevPartner profiler and it shows that problem is with QT and WebKit integration. Application spend lot of time in function QPixmap::fromWinHBITMAP() in GraphicsContext::releaseWindowsContext() (C:\Qt\4.5.2\src\3rdparty\webkit\WebCore\platform\graphics\GraphicsContext.cpp). We analysed releaseWindowsContext() function and think that translation from HDC to QPixmap is not optimal solution. Source code below: GraphicsContext::releaseWindowsContext() ... HBITMAP bitmap = static_cast<HBITMAP>(GetCurrentObject(hdc, OBJ_BITMAP)); BITMAP info; GetObject(bitmap, sizeof(info), &info); ASSERT(info.bmBitsPixel == 32); QPixmap pixmap = QPixmap::fromWinHBITMAP(bitmap, supportAlphaBlend ? QPixmap::PremultipliedAlpha : QPixmap::NoAlpha); m_data->p()->drawPixmap(dstRect, pixmap); We think that it will be better to draw HDC directly on the screen without translation to QPixmap. 155472 1 kenneth 2009-10-18 08:33:46 -0700 This seems Windows related, I'm changing platform to Windows from Mac OS X 182687 2 davidtlwong 2010-01-20 02:40:51 -0800 Is it similar problem of https://bugs.webkit.org/show_bug.cgi?id=24913#c1 ?