This patch implements support for icons in user-defined menus into Openbox

Image loading is done using the Imlib2 library.
I chose Imlib2 because it's pretty fast, it's easy to use, supports many file
formats (tested xpm, gif, jpeg, png) and doesn't introduce too much bloat (it
depends :)).

I ported the patch to 3.4.7-pre3 and added some enhancements. Caching is much
better now, and icons can be disabled at compile time using --disable-imlib2
option.

What's new?
Syntax of configuration files (namely rc.xml and menu.xml) has been changed
slightly to allow users to associate icons to menu entries. This is done by
specifying path to icon file in the new "icon" attribute in "<item>" element,
e.g:
<item label="Vim" icon="/usr/share/pixmaps/vim-32.xpm">
  <action name="Execute"><execute>x-terminal-emulator -T Vim -e
vim</execute></action>
</item>

If user doesn't want to display any icons in his user-defined menus, he/she can
disable icons in rc.xml, inside "<menu>" section:
<menu>
 ...
  <showIcons>no</showIcons>
 ...
</menu>
Default value is "yes".
(New boolean variable "config_menu_user_show_icons" has been added to source
code.)

An icon is loaded (using menu_item_attach_icon()) when a new entry of menu is
created. Fortunately, I haven't notice any performance problems because of this
:).

1 files changed, 135 insertions, 0 deletions

diff --git a/openbox/imageload.c b/openbox/imageload.c
new file mode 100644
index 00000000..c80aa134
--- /dev/null
+++ b/openbox/imageload.c
@@ -0,0 +1,135 @@
+/* -*- indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*-
+   imageload.c for the Openbox window manager
+   by Libor Kadlcik (aka KadlSoft)
+*/
+
+/*
+    All loaded images are cached. There's no separate cache for the images,
+    instead they are simply stored in image cache (RrImageCache) as RrImages,
+    ready to be used.
+    Every RrImage loaded from file is associated with name of the file. This is
+    done by file name table (RrImageCache.file_name_table), which is a simple
+    hash table, where file names are keys to pointers to RrImage.
+    If you request to load file that is already in image cache, nothing will be
+    loaded and you just got the RrImage from cache.
+    When RrImage is destroyed (see RrImageDestroyNotify), the file name - pointer
+    to RrImage pair is removed from the file name table.
+*/
+
+#include "debug.h"
+#include "menu.h"
+#include "openbox.h"
+#include "gettext.h"
+#include "obrender/render.h"
+#include "obrender/image.h"
+#include "obrender/imagecache.h"
+#include "imageload.h"
+#include <Imlib2.h>
+
+
+static void CreateFileNameTable(RrImageCache *self)
+{
+    g_assert(self->file_name_table == NULL);
+    self->file_name_table = g_hash_table_new(&g_str_hash, &g_str_equal);
+}
+
+static void DestroyFileNameTable(RrImageCache *self)
+{
+    g_assert(g_hash_table_size(self->file_name_table) == 0);
+    g_hash_table_destroy(self->file_name_table);
+    self->file_name_table = NULL;
+}
+
+/*! Return file name from which this image has been loaded. */
+static gchar* GetFileName(RrImage *image)
+{
+    GHashTableIter iter;
+    void *key, *value;
+
+    g_hash_table_iter_init(&iter, image->cache->file_name_table);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        if (value == image)
+            return key;
+    }
+    return NULL;
+}
+
+/* RrImage is about to be deleted. So remove it from file name table. */
+static void RrImageDestroyNotify(RrImage *image)
+{
+    gchar *file_name = GetFileName(image);
+    g_assert(file_name != NULL);
+    ob_debug("Image \"%s\" no longer needed\n", file_name);
+    g_hash_table_remove(image->cache->file_name_table, file_name);
+    g_free(file_name);
+
+    if (g_hash_table_size(image->cache->file_name_table) == 0) {
+        ob_debug("No RrImage in file_name_table, destroying\n");
+        DestroyFileNameTable(image->cache);
+    }
+}
+
+#if (RrDefaultAlphaOffset != 24 || RrDefaultRedOffset != 16 \
+    || RrDefaultGreenOffset != 8 || RrDefaultBlueOffset != 0)
+#error RrImageFetchFromFile cannot handle current bit layout of RrPixel32.
+#endif
+
+/*! Load image from specified file and create RrImage for it (RrImage will be
+    linked into specified image cache). Reference count of the RrImage will
+    be set to 1.
+    If that image has already been loaded into the image cache, RrImage
+    from the cache will be returned and its reference count will be incremented.
+*/
+RrImage* RrImageFetchFromFile(RrImageCache *cache, const gchar *name)
+{
+    RrImage *rr_image, *found_rr_image;
+    gint w, h;
+    DATA32 *ro_data;
+
+    imlib_set_color_usage(128);
+
+    if (cache->file_name_table == NULL)
+        CreateFileNameTable(cache);
+
+    /* Find out if that image has already been loaded to this cache. */
+    rr_image = g_hash_table_lookup(cache->file_name_table, name);
+    if (rr_image && rr_image->cache == cache) {
+        ob_debug("\"%s\" already loaded in this image cache.\n", name);
+        RrImageRef(rr_image);
+        return rr_image;
+    }
+
+    Imlib_Image imlib_image = imlib_load_image(name);
+    if (imlib_image == NULL) {
+        g_message(_("Cannot load image from file \"%s\""), name);
+        return NULL;
+    }
+
+    /* Get data and dimensions of the image. */
+    imlib_context_set_image(imlib_image);
+    g_message("Alpha = %d\n", imlib_image_has_alpha());
+    ro_data = imlib_image_get_data_for_reading_only();
+    w = imlib_image_get_width();
+    h = imlib_image_get_height();
+    ob_debug("Loaded \"%s\", dimensions %dx%d\n", name, w, h);
+
+    /* There must not be any duplicated pictures in RrImageCache. */
+    found_rr_image = RrImageCacheFind(cache, ro_data, w, h);
+    if (found_rr_image) {
+        rr_image = found_rr_image;
+        RrImageRef(rr_image);
+        ob_debug("Image \"%s\" is duplicate\n", name);
+    }
+    else {
+        /* Create RrImage from the image and add it to file name table. */
+        rr_image = RrImageNew(cache);
+        RrImageSetDestroyFunc(rr_image, &RrImageDestroyNotify);
+        /* XXX: Is Imlib2's format of DATA32 always identical to RrPixel32? */
+        RrImageAddPicture(rr_image, ro_data, w, h);
+        g_hash_table_insert(cache->file_name_table, g_strdup(name), rr_image);
+    }
+
+    imlib_free_image();
+
+    return rr_image;
+}