Re: Forcing GtkScrolledWindow to sroll

[David NeÄas <yeti physics muni cz>]

On Mon, Jan 11, 2010 at 01:51:06PM -0500, Tim Corio wrote:
> I couldn't find this in the archives, but I assume it's a common thing.
>
> How do I force a GtkScrolledWindow to scroll?

You can either use gtk_range_set_value() on the scrollbar obtained with
gtk_scrolled_window_get_hscrollbar()/gtk_scrolled_window_get_vscrollbar()
or gtk_adjustment_set_value() on the adjustments obtained by similar
functions.

> Using the C API, I have a drawing area widget that I put into a scrolled
> window.  I can scroll the image as expected by dragging the scrollbars.
> Now, I want to first, force the viewport to be scrolled to the center of
> the image.  The I want to implement a "drag" scrolling.  The user will
> click and drag the image to make it scroll.

Generally, you don't want to do this because it is inefficient if the
image is large.  Do not allocate a larger drawing area than the visible
part, do not use a viewport and, instead, just draw the visible part of
the image according to the scrollbar positions in the expose event.

Yeti