Creating themeable custom stock icons

[Andrew Conkling <andrew conkling gmail com>]

I've talked with Owen on IRC a few times about how to theme custom
stock icons from various GTK+ programs.  Basically, what he said came
down to using some specific code from iconfactory.c.  As this didn't
seem to be documented (and I don't know C), I got some help from
muntyan on IRC, who was able to figure out how to do this.  (Below is
his working code.)

My questions are thus: Is that code a good example of what to do so
that custom stock icons are themable?  If so, can this be documented
somewhere?  My goal is to patch said programs and email the devs, but
I want to know what will work. :)

Regards,
Andrew Conkling

/*
 *   @(#)$Id: moostock.c,v 1.3 2005/05/29 11:39:03 emuntyan Exp $
 *
 *   Copyright (C) 2004-2005 by Yevgen Muntyan <muntyan math tamu edu>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   See COPYING file that comes with this distribution.
 */

#include "mooutils/moostock.h"
#include "mooutils/moocompat.h"
#include "mooutils/stock-terminal-24.h"
#include <gtk/gtk.h>

#if !GTK_CHECK_VERSION(2,6,0)
#include "mooutils/stock-about-16.h"
#include "mooutils/stock-about-24.h"
#include "mooutils/stock-edit-16.h"
#include "mooutils/stock-edit-24.h"
#endif


#if GTK_CHECK_VERSION(2,4,0)

static void register_stock_icon     (GtkIconFactory *factory,
                                     const gchar    *stock_id)
{
    GtkIconSet *set = gtk_icon_set_new ();
    GtkIconSource *source = gtk_icon_source_new ();

    gtk_icon_source_set_icon_name (source, stock_id);
    gtk_icon_set_add_source (set, source);

    gtk_icon_factory_add (factory, stock_id, set);
    gtk_icon_set_unref (set);
    gtk_icon_source_free (source);
}


static void add_default_image (const gchar  *stock_id,
                               gint          size,
                               const guchar *inline_data)
{
    GdkPixbuf *pixbuf = gdk_pixbuf_new_from_inline (-1, inline_data,
FALSE, NULL);
    g_return_if_fail (pixbuf != NULL);

    gtk_icon_theme_add_builtin_icon (stock_id, size, pixbuf);

    g_object_unref (pixbuf);
}


static void add_icon    (GtkIconFactory *factory,
                         const gchar    *stock_id,
                         gint            size,
                         const guchar   *data)
{
    add_default_image (stock_id, size, data);
    register_stock_icon (factory, stock_id);
}

static void add_icon2   (GtkIconFactory *factory,
                         const gchar    *stock_id,
                         gint            size1,
                         const guchar   *data1,
                         gint            size2,
                         const guchar   *data2)
{
    add_default_image (stock_id, size1, data1);
    add_default_image (stock_id, size2, data2);
    register_stock_icon (factory, stock_id);
}


void moo_create_stock_items (void)
{
    static gboolean created = FALSE;
    GtkIconFactory *factory;

    if (created) return;
    else created = TRUE;

    factory = gtk_icon_factory_new ();

    gtk_icon_factory_add_default (factory);

    add_icon (factory, MOO_STOCK_TERMINAL,
              24, MOO_GNOME_TERMINAL_ICON);

#if !GTK_CHECK_VERSION(2,6,0)
    add_icon2 (factory, GTK_STOCK_ABOUT,
               24, STOCK_ABOUT_24,
               16, STOCK_ABOUT_16);
    add_icon2 (factory, GTK_STOCK_ABOUT,
               24, STOCK_EDIT_24,
               16, STOCK_EDIT_16);
#endif

    g_object_unref (G_OBJECT (factory));
}


#else /* !GTK_CHECK_VERSION(2,4,0) */

/* TODO: take code from gtk */

void moo_create_stock_items (void)
{
    static gboolean created = FALSE;
    GtkIconSet *set = NULL;
    GdkPixbuf *pixbuf = NULL;
    GtkIconFactory *factory;

    if (created) return;
    else created = TRUE;

    factory = gtk_icon_factory_new ();
    gtk_icon_factory_add_default (factory);

    pixbuf = gdk_pixbuf_new_from_inline (-1, MOO_GNOME_TERMINAL_ICON,
FALSE, NULL);
    if (pixbuf) {
        set = gtk_icon_set_new_from_pixbuf (pixbuf);
        gdk_pixbuf_unref (pixbuf);
    }
    else
        set = gtk_icon_set_new ();
    gtk_icon_factory_add (factory, MOO_STOCK_TERMINAL, set);
    gtk_icon_set_unref (set);

    pixbuf = gdk_pixbuf_new_from_inline (-1, STOCK_ABOUT_24, FALSE, NULL);
    if (pixbuf) {
        set = gtk_icon_set_new_from_pixbuf (pixbuf);
        gdk_pixbuf_unref (pixbuf);
    }
    else
        set = gtk_icon_set_new ();
    gtk_icon_factory_add (factory, GTK_STOCK_ABOUT, set);
    gtk_icon_set_unref (set);

    pixbuf = gdk_pixbuf_new_from_inline (-1, STOCK_EDIT_24, FALSE, NULL);
    if (pixbuf) {
        set = gtk_icon_set_new_from_pixbuf (pixbuf);
        gdk_pixbuf_unref (pixbuf);
    }
    else
        set = gtk_icon_set_new ();
    gtk_icon_factory_add (factory, GTK_STOCK_EDIT, set);
    gtk_icon_set_unref (set);

    g_object_unref (G_OBJECT (factory));
}

#endif /* !GTK_CHECK_VERSION(2,4,0) */