I used a GtkScrolledWindow with a GtkDrawingArea inside it for OpenGL drawing 
in my program. I found that yes, I did have to set_size_request when zooming in 
and out.

Be warned: Due to the way resizing works in GTK+, it's impossible to do "smooth 
zooming" where your scrolled window remains focused on the same part of the 
image as you zoom. You can approximate it, but the zoom itself will be jerky. I 
haven't found any way around this.
I have been reading about the gtk layout widget and that it has native 
scrolling. If I were to use the gtk layout instead, would that scroll without 
having to resize it?

________________________________

From: Diego Rivera [mailto:[EMAIL PROTECTED]
Sent: Sat 5/10/2008 4:35 PM
To: Ariel Martinez
Cc: gtk-list@gnome.org
Subject: Re: Scrolling a drawing area


The GtkDrawingArea isn't a common container, unlike a GtkWindow or something. 
Drawing a pixmap bigger than the GtkDrawingArea itself, won't change the size 
of the GtkDrawingArea, pixels out of range from the size of the drawing_area 
are just clipped away (they aren't in the visible portion of the 
GtkDrawingArea, so they are ignored).

>From my point of view, the gtk_set_size_request() call is required if you want 
>your GtkDrawingArea to be the size of the pixmap you are drawing into it.

Regards,
Diego


2008/5/10 Ariel Martinez <[EMAIL PROTECTED]>:


        I am using gtk_scrolled_window_add_with_viewport() to get scrolling 
capabilities for a drawing area. In my program, I am drawing to a backing 
pixmap which I in turn draw onto the drawing area with an expose event handler. 
The problem  I am having is that even though the pixmap is larger than the 
drawing area, the drawing area does not scroll.  If however, I use 
gtk_set_size_request() on the drawing area to increase its dimensions, the 
drawing area scrolls. Any suggestions on what I could be doing wrong? Thanks.

         


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