Webkit text rendering performance

I ran into a problem while using the QWebView to display text, which can be moved around in the view. After adding quite some text (some thousand characters) performance drops significantly. Movement become choppy, and the processor core is fully utilized. Some digging around using vtune, narrows down the problem to QWindowsFontEngine::getOutlineMetrics(...) in the windows call getGlyphOutline.

This has been tested on:

• Windows 8 Qt MSVC 2010 32bit - 5.0.1

• Windows 7 Qt MinGW 32bit - 5.0.1

• Windows 7 Qt MSVC 2012 64bit - 5.0.2 latest

• Linux GCC 64bit Qt 5.0.1

The problem persists on all windows versions, while it performs nicely on linux (no surprise since the problem seems to be in the QWindowsFontEngine).