#9064: An invalidated BView does not draw to a BBitmap
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Reporter: axeld | Owner: nobody
Type: bug | Status: assigned
Priority: high | Milestone: R1
Component: Servers/app_server | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Platform: All |
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Comment (by Jim906):
I think the problem relates to the fact that BBitmap::fWindow cannot
receive messages because it is an offscreen BWindow, which means Run is
never called.
BView::Invalidate sends an AS_VIEW_INVALIDATE_RECT message to the
OffscreenWindow that corresponds to fWindow. The OffscreenWindow, in
response, sends back an _UPDATE_ message. Since fWindow can't receive
messages, it does not make the expected reply (AS_BEGIN_UPDATE) to the
OffscreenWindow. This leaves the OffscreenWindow in a state where
fUpdateRequested is true and fInUpdate is false. In this state,
Window::GetEffectiveDrawingRegion will decide that the invalidated area
can't be drawn to.
This situation can be avoided if OffscreenWindow's base member
Window::fUpdatesEnabled is false, because then Window::_SendUpdateMessage
won't send the _UPDATE_ message and won't set fUpdateRequested to true.
Suggested patch: https://review.haiku-os.org/c/haiku/+/5967.
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Ticket URL: <https://dev.haiku-os.org/ticket/9064#comment:2>
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The Haiku operating system.
