Re: gtk_widget_draw()

[Federico Mena Quintero <federico ximian com>]

On Wed, 2010-08-18 at 09:37 +0200, Alexander Larsson wrote:

[Border around windows so you can "glow" around a widget]
> There are all sorts of ways you can hack it into GtkButton or any
> specific widget, I'm sure. However, its hard to do in a more generic way
> for a theme. I was thinking the theme could just set a style property to
> have the widget enlarge its border, and then the theme just draws a bit
> outside in its normal rendering operation. No hacks, no special code,
> works for all widgets.

Hmm.  I just think it's overkill to complicate the GdkWindow abstraction
just for themes' sake.

Correct me if I'm wrong, but I think you imagine the
glow-around-a-button to actually have allocated space around the button

   ************
   * +------+ * +------+
   * |button| * |button|
   * +------+ * +------+
   ************

while I'm imagining that the glow actually overlaps anything around the
widget

   **************
   *  +------+ +*-----+
   *  |button| |*utton|
   *  +------+ +*-----+
   **************

The latter is doable if the theme creates a temporary window as a child
of the toplevel, on top of all the other subwindows.

[Do we just lack the "don't clip" flag on windows]
> To fully take advantage of it we would also like to remove no-window
> widgets in Gtk and make getting a "standard" window easy via some
> default realize handler setup.

I guess InputOnly windows are trivial when we get the transparent
windows we've been talking about - you just never draw to them.  Old
apps could still use them to get events.

Getting rid of no-window widgets would be trivial in GTK+, but it would
break a lot of code that already uses that trick and does all the
coordinate-munging on its own... maybe we should make "no-window" mean
"you won't know it, but you really get a cairo_t with a transformation
relative to your parent widget"?  That way you still have to make the
changes to take a cairo_t instead of a GdkWindow (for the draw()
method), but you don't have to change your delicate code that deals with
coordinates.

  Federico