Re: GdkPixmap bugs

[Ron Steinke <rsteinke w-link net>]

> From: Owen Taylor <otaylor redhat com>
>
> Ron Steinke <rsteinke w-link net> writes:
>
> > > From: Owen Taylor <otaylor redhat com>
> > >
> > > And the colormap handling in gdk_pixmap_new() needs special-casing 
> > > for the case where the depth of the window is not the
> > > same as the depth of the new pixmap. In the case where
> > > depth == 1, we may be able to supply a proper default colormap,
> > 
> > How would you go about creating a GdkVisual of depth 1?
>
> Thinking about it before ... my comment is really nonsensical.
>
> The right thing to do when creating a pixmap where the depth of the
> pixmap doesn't match the depth of the supplied window (or the root
> window, if window is passed in as NULL), is always to leave the
> colormap unset.
>
>
> You can't actual "create" a visual - the set of visuals is fixed.
>
> X's model is actually a little bizarre - you can create pixmaps of
> depths for which there is no corresponding visual and colormap. (The
> list of allowed depths for a screen can be retrieved with
> XListDepths(), something not exposed through GTK+)
>
> The uses of this are:
>
>  - For traditional X rendering, depth 1 bitmaps for masks,
>    XCopyPlane, etc.
>
>  - For the Xrender extensions, alpha masks, 24 bit images offscreen
>    images, etc.

So what is the correct Gdk way of doing things like:

reading the bitmap data, a la gdk_get_image()

setting the foreground color of the bitmap graphics context
so that you can use the drawing routines, e.g. gdk_draw_polygon()

Ron