Re: Obscure timing issue

[Fred Kiefer]

Fred Kiefer wrote:
> The bigger issue is that the redraw takes so long. Here it could be that
> we draw too much, but it could also be that we just flush too much over
> to X. The first issue should be simple to detect, we just need to put a
> write statement before the call to drawRect: in NSView and see whether
> we try to do too much here. The second issue is a bit harder, here we
> need to start off in NSWindow flushWindow and try to understand that
> method as well as the draw rectangle handling in NSView and what the
> graphics context does when flushing.
> 

I looked into this drawing code tonight, but it will take more time to
come up with conclusions. From what I can say now it doesn't look like
we are drawing too much. (I had the impression there might be a problem
with image caching, but this is a separate issue.) This was rather easy
to test by just setting the argument "--GNU-Debug=NSView" when running
an application and inspecting the output.
On the flushing I am not that sure what is happening. Here the
interaction between the NSView and the NSWindow is rather complex and it
may help to introduce a few helper methods to make clearer what goes on.