Re: Invisible GtkImage

[Kip Warner <kip thevertigo com>]

> Hi Kip,
> After setting the rescaled image, you should probably "Chain Up" to the
> default size_allocate method.
>
> I'm not a python expert, but I believe
>
> Gtk.Image.do_size_allocate(self, allocation)

Hey Andrew. You are right. I had no idea that that had to be done, but
based on my knowledge of other windowing toolkits and the underlying
native implementation, what you suggest makes sense.

> at the end of your override should work. Looking at the implementation, the
> allocation needs to be stored in GtkWidget's private structure. Without
> chaining up, the allocation is never stored, and thus when on_draw() is
> called it is likely making a 0x0 sized Cairo context.

That makes sense, but should the allocation passed to the base class's
do_size_allocate() be the original allocation parameter that was passed
into the override, or the one that I modified to contain the new image
dimensions adjusted to maintain the aspect ratio?

If I use the allocation passed into the override, the pixels in the
image appear to rescale appropriately, but the image as a whole does
not. It grows horizontally, but the height of the widget remains fixed.

Any suggestions? The image is being added to the GtkAssistant page as
such...

        page._bannerImage = BannerImage() #Gtk.Image()
        page.pack_start(page._bannerImage, False, False, 0)
        page.reorder_child(page._bannerImage, 0)

Thanks for your help.

-- 
Kip Warner -- Software Engineer
OpenPGP encrypted/signed mail preferred
http://www.thevertigo.com