Re: Image resizing

[Andrew Potter <agpotter gmail com>]

On Sat, Jun 8, 2013 at 10:27 PM, Kip Warner <kip thevertigo com> wrote:

> The banner image should automatically resize as the window is resized.
> It should use the full width available in the parent page (GtkBox), but
> the image's height should be calculated as a function of the aspect
> ratio to keep it from being distorted.
> I don't want the scrollbars to ever appear and the full image to always
> be visible. Any help appreciated.

One approach is ditching the ScrolledWindow and overriding the
 get_preferred_width_for_height/width() vfuncs to return the full image
width, and then in size_allocate() set the image to a scaled pixbuf of the
allocated width.

This involves making a subclass which is a little bit of work if you've
never done it before (especially in straight C).

The only example I have on hand [1] is in Gtkmm and does quite a bit more
than you need (Animated image support, toggling between thumbnail and full
size). But overriding these functions  should be enough:
size_allocate()
get_preferred_height()
get_preferred_width_for_height()
get_preferred_width()
get_preferred_height_for_width()

[1] https://github.com/talisein/Horizon/blob/master/src/horizon_image.cpp