[gtkada] inserting a xpm image

[Bobby D. Bryant]

caleb baker wrote:

> hi
>
> i'm trying to load an xpm image into a gui and i'm using pixmap and i'm
> having trouble doing this.
>
> i'm using the code
>
>    colour := white(Gtk.Widget.Get_Default_Colormap);
>    Clear(Graphics_window);
>    Set_Background (Graphics_window, colour);
>    Gdk.Bitmap.Gdk_New (mask, Graphics_window, 250, 250);
>    Create_From_Xpm (pic, Graphics_window, mask, colour, Image_file);
>
> and it's complaining that graphics_window is null, i have looked the the
> Gdk-window.ads and i can't find anything which sets what the graphics window
> actually has in it.

It's a bit hard to tell without seeing your declarations.  I presume
Graphics_Window is a Gdk.Window.Gdk_Window?  If so, you can initialize it by
calling Gtk.Window.Get_Window and passing your main Gtk_Window as an argument.
(That call finds the Gdk_Window associated with a Gtk_Window.)

However, you will have a similar problem if the Gtk_Window is null when you
make that call, so you need to either "show" or "realize" your Gtk_Window
before you try to find its associated Gdk_Window.  Since your window is
apparently not ready for showing yet, I recommend calling Gtk.Window.Realize
and passing your main Gtk_Window as the argument, just before you try the call
above to find its Gdk_Window.  (The .Realize apparently generates some internal
data structures that you need before making the Get_Window call.)


> also i'm not sure how to show it

I may not be doing this the most elegant way, but here's an overview of what
works for me:

 o Create a Gdk_Pixmap for your "offscreen" pixmap, using Create_From_Xpm
similarly to above.

 o Create a Gtk_Pixmap for you "onscreen" pixmap and simultaneously bind it to
your "offscreen" pixmap with Gtk.Pixmap.Gtk_New.

 o Pack the Gtk_Pixmap into a Gtk_Window.

 o Show the Gtk_Window.

You can find all this in the testgtk program that ships with GtkAda.  Most of
the interesting stuff is in create_pixmap.adb, though the creation of the
top-level window is done elsewhere in the code.

Good luck,

Bobby Bryant
Austin, Texas