Re: Widget Peek functions

[Owen Taylor <otaylor redhat com>]

Tim Janik <timj@gtk.org> writes:

> On Tue, 29 Feb 2000, Karl Nelson wrote:
> 
> > 
> > The Gtk-- crew was trying to implement a quick and dirty image
> > loader so that we can load images prior to realization for 
> > some applications.  This involved loading the pixmap with the
> > colormap from the top of the gtk+ colormap stack.  
> > 
> > Unfortunately it appears like the colormap is so protected that
> > it is unaccessible.  You can view the default colormap but not
> > the colormap you are about to create with.  Was this intentional?  
> > It is possible that the gtk_widget_peek_* functions can be exposed 
> > to the user?  (if not in the header at least as a symbol that we can
> > link to.)  Considering there is no way to alter it through the peek
> > functions, I don't understand why they are so guarded.
> 
> they weren't really used outside of gtkwidget.c yet.
> you're probably right in wanting to be able to figure the last colormap
> set. however exposing gtk_widget_peek_* will leave us with:
> 
> void         gtk_widget_push_style           (GtkStyle   *style);
> void         gtk_widget_push_colormap        (GdkColormap *cmap);
> void         gtk_widget_push_visual          (GdkVisual  *visual);
> void         gtk_widget_push_composite_child (void);
> void         gtk_widget_pop_composite_child  (void);
> void         gtk_widget_pop_style            (void);
> void         gtk_widget_pop_colormap         (void);
> void         gtk_widget_pop_visual           (void);
> void         gtk_widget_set_default_style    (GtkStyle    *style);
> void         gtk_widget_set_default_colormap (GdkColormap *colormap);
> void         gtk_widget_set_default_visual   (GdkVisual   *visual);
> GtkStyle*    gtk_widget_get_default_style    (void);
> GdkColormap* gtk_widget_get_default_colormap (void);
> GdkVisual*   gtk_widget_get_default_visual   (void);
> /* newly added */
> GtkStyle*    gtk_widget_peek_style           (void);
> GdkColormap* gtk_widget_peek_colormap        (void);
> GdkVisual*   gtk_widget_peek_visual          (void);
> 
> i think a better choice would be to make
> 
> GtkStyle*    gtk_widget_get_default_style    (void);
> GdkColormap* gtk_widget_get_default_colormap (void);
> GdkVisual*   gtk_widget_get_default_visual   (void);
> 
> be effectively what the peek functions currently do
> to keep the API simple (read: less complex).
> 
> though that is a semantic change in some sense,
> gtk_widget_get_default_* aren't really used that much
> and applications usually use them as if they actually
> were the peek variants.
> the only thing i see that actually needs changing after
> this, is gtkentry.c and gtktext.c that need to compare their
> colormaps against gdk_colormap_get_system() for the
> GDK_IC_PREEDIT_COLORMAP attribute.
> 
> owen, you see problems with that change?

Yes. get_default_style() needs to be in a pair with set_default_style() - 
they shouldn't do different things.

I think Karl's need for the peek functions should be resolved in a different
way now - simply by removing the need to access the colormap for image
handling. If we do need the functionality, then I would want to simply
expose the peek() functions under their current names.

Regards,
                                                       Owen