On May 11, 2009, at 11:58 AM, lkcl wrote:
Paul Pedriana-3 wrote:
The ScrollView::paint function seems wrong to me too.
The function source is shown below. I don't understand why it uses
context->clip(visibleContentRect()) without accounting for
documentDirtyRect. Shouldn't it make a union of visibleContentRect
and
documentDirtyRect? I am writing my own graphics back-end and this
lack
of clipping is messing up the view drawing.
Clipping to the dirty rect is done by WebKit right now. It would be
nice to eventually make that code a bit more cross-platform. You can
look at WebView.cpp in webkit/win to see the Windows version and
WebHTMLView.mm on Mac to see the Mac version. Basically there are
some heuristics for studying the dirty regions passed in as decomposed
rectangles and deciding whether to just do a single paint of the
region's bounding box rect or to do individual paints of the
decomposed region's rects. By the time you get into
ScrollView::paint, you're supposed to already be clipped to the single
rect that you happen to be drawing (either the union or a singleton
from the region's rect list).
dave
([email protected])
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