From: Joaquin Cuenca Abela (e98cuenc@yahoo.com)
Date: Wed Nov 13 2002 - 15:56:37 EST
--- "j.m.maurer" <j.m.maurer@student.utwente.nl>
wrote:
> > The problem about the status bar not working with
> > double buffering is there because xft calls (as
> any
> > non gdk primitives) don't get diverted to the
> double
> > buffer, so all the things that we draw in a double
> > buffered GdkWindow using non gdk calls are covered
> by
> > the double buffer when gdk copies it on the
> GdkWindow
> > at the end of the expose event (you can see it
> that's
> > the problem with the status bar if it flicker a
> very
> > little bit before it disappears).
>
>
> Please forgive my ignorance, but could this also be
> the problem that
> when the Font Preview is first shown, it is being
> grayed out only a few
> miliseconds later ?
Yes, maybe. The usual symptoms are a quick flicker
before disappearing. Also, if you don't honour the
clip rectangle in the expose event, then you will only
see the part that you draw outside the clip rectangle
(as the clip rectangle will be covered by the double
buffer), and the clip rectangle will be drawn with
1) the gdk_draw* calls that you use in the expose
event
2) the background color/pixmap for this GdkWindow for
these parts not covered by 1) (gray by default)
So that means:
* gray on first expose (as the clip rectangle is the
whole window)
* seems to work on scrolling (if the expose event
don't honours the clip rectangle at all), except for
the lower/upper part of the window if you're scrolling
up/down.
* seems to work if you pass another window over the
bogus window, and you uncover the bogus window slowly.
...
if these are the symptoms of the Font Preview, then I
guess that you're seeing this bug. If that's the
case, Martin's fixes should have fixed your problem,
also.
Hope that it helps,
Cheers,
=====
Joaquin Cuenca Abela
e98cuenc at yahoo dot com
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