Re: GtkLabel, GtkMisc, alignment and containers; an idea

[Behdad Esfahbod <behdad behdad org>]

On 07/07/2009 09:53 AM, Davyd Madeley wrote:
> So, I was looking at why a GtkLabel with a RTL control code didn't seem
> to right-align the text in a GtkLabel. The answer being that the width
> of the PangoLayout is set to -1, rather than the width of the
> allocation.
>
> So I was wondering how you'd fix this. My immediate thought was to set
> the PangoLayout to always have the width of the allocation. This would
> allow for RTL control codes to function + make the justify modes in
> GtkLabel work how people think they should (rather than how they do).
>
> Unfortunately it breaks gtk_misc_set_alignment(), you can no longer
> align a smaller PangoLayout inside a bigger allocation.
>
> Thus I was thinking about how this might be fixed properly, and I came
> up with the following idea. It breaks API and assumptions in GTK+, and I
> don't yet have an idea for a migration path; but I'll share it anyway.
>
> My idea:
>
> (1) Make alignment a child-property of the GtkContainer. This would
> allow any widget that wasn't EXPAND|FILL to be aligned within it's
> available space. It would remove the requirement for GtkAlignment in a
> lot of cases. This could be added to GTK+ without breaking API.
>
> (2) Remove the GtkMisc class. Alignment is now a child-property.
>
> (3) Make the PangoLayout of labels always fill their allocation. This
> would make features like the RTL control code and PangoJustify work as
> developers expect. If developers want a left-justified, right-aligned
> text block, they can set the widget to not be EXPAND|FILL, and set the
> align-x child-property to 1.0. This will likely require extended layout
> for wrapped labels.
>
> (4) Profit.
>
> Thoughts?

Generally agreed.  Makes the code so much simpler...

behdad