Re: (1) How to implement Image Buttons without gaps? (2) Can GtkImage stretch an image automatically?

[Christian Dywan <christian imendio com>]

Am Wed, 20 Aug 2008 17:07:00 -0700
schrieb Daniel Yek <dyek real com>:

> [I sent this gtk-app-devel-list earlier, but I suppose this list
> might have an answer for me.
> I'm just trying to figure things out...]
> 
> Hi,
> 
> (1) I have been looking for a way to use GtkButton to create an Image
> Button that is exactly of the same size as the GtkImage that it
> contains, so that two Image Buttons next to each others would leave no
> gap in between.
> 
> I have some ideas in mind, but I wonder if I'm going to
> over-engineering them and if there is a well-known approach to solve
> this, supposedly, common problem.
> 
> For this first issue, this is the main idea that I am considering to
> investigate:
> (1a) Subclassing GtkButton and force it to allocate the size of the
> GtkImage it contains and overwrite all its drawing functionalities
> that cause non-image area to appear around GtkImage. If focus or
> default lines are to be drawn, draw them on the inside edge of
> GtkImage or suppress them entirely if necessary.
> 
> I haven't looked into GtkButton source code lately, but I think this
> approach can potentially boil down to reimplementing the entire button
> from scratch to derive from GtkWidget, if GtkButton turns out to not
> allow a subclass to override certain drawing function. Reimplementing
> a new button widget can cause deviation in functionalities in future
> GTK+ releases and I want to avoid if there is a better solution
> available.
> 
> I am hoping someone would point out to me an easier way to accomplish
> this.
> 
> If GtkButton simply is not able to function as Image Buttons without
> gap, I wonder if GTK+ developers considered the usage during the
> process of GtkButton implementation/development? I wonder if the
> usage model was intentionally excluded (for reasons that I am
> obviously not sure of -- maybe for memory efficiency reasons; or for
> theming reasons)? Or is it simply the case that it wasn't implemented
> yet? Or is this usage model really unusual?

Hey Daniel,

you are not the first person with such a question, I see people asking
that in the IRC about once a month.

Basically you should not try to use a button only to try to suppress
all its functionality, and that is what you are trying to do here. A
button that draws only an image but not any other features of a button
can just as well be that, an image.

So the solution is as simple as putting an image in an event box and
connecting your signals. Unless there's a special requirement you
didn't mention, that's all you need.

ciao,
    Christian