Re: Changing Text Color for GTK_ENTRY Widgets

[Emmanuel Rodriguez <emmanuel rodriguez gmail com>]

2009/2/26  <r richardparker comcast net>:
> I have several top-level windows which contain fill-in forms designed with
> GLADE 3 that contain GtkTextEntry Widgets for data to be stored in a
> PostgreSQL database. I'm validating the entries and when I find one that's
> invalid, I'd like to change its text color to "red" and then post a message
> box indicating that there were errors on the form. How do I change the text
> color in these GTK_ENTRY widgets? These are not labels, but single-line text
> entry fields. I'm guessing that Pango would be involved, but how? As it is,
> a section of my validation code is as follows:
>

Here's a derived GtkEntry (in Perl) that can use Pango markup:

http://cpansearch.perl.org/src/POTYL/Gtk2-Ex-Entry-Pango-0.04/lib/Gtk2/Ex/Entry/Pango.pm

If you download the bundle you will see some sample code how I use it.
The code should be straight easily portable to any language.

>
>
>
> All the code is in C, using Gtk+. The forms (windows) were designed with
> GLADE 3, but GLADE doesn't offer a way to "markup" GtkEntry widgets, so I
> don't think I can just store markup code into the erroneous entries.
>
If you are using glade you will need to either create the entry fields
that will use Pango as custom widgets or simply merge the code
yourself. I have an application where the GUI is made through Glade
and I found it easier to use a generic GtkEntry created by Glade and
to simply add the proper callbacks to the widget.

>
>
> Any suggestions?
Using Pango in a GtkEntry is tricky. This is because the GtkEntry uses
the MVC pattern. The text in the field is handled by Model but the
text displayed is handled by the view. GtkEntry makes a distinction
between both. If you change the data displayed through Pango it will
not be permanent. The next redraw will erase your changes because the
widget will simply perform the redraw based on the data stored. This
problem can be easily be addressed by adding our own callback that
will ensure that the widget is always drawn using Pango when needed.

-- 
Emmanuel Rodriguez