[totem] gst: Add helper to get the best available cover image

[Bastien Nocera <hadess src gnome org>]

commit 68c8664b16ad4c0acc102193c652d3af64cd5a5e
Author: Bastien Nocera <hadess hadess net>
Date:   Tue Apr 5 15:48:59 2011 +0100

    gst: Add helper to get the best available cover image
    
    Thus saving us the trouble of doing that.

 src/gst/totem-gst-helpers.c |   88 +++++++++++++++++++++++++++++++++++++++++++
 src/gst/totem-gst-helpers.h |    2 +
 2 files changed, 90 insertions(+), 0 deletions(-)
---
diff --git a/src/gst/totem-gst-helpers.c b/src/gst/totem-gst-helpers.c
index 16af82b..72db90a 100644
--- a/src/gst/totem-gst-helpers.c
+++ b/src/gst/totem-gst-helpers.c
@@ -30,6 +30,7 @@
  *
  */
 
+#include <gst/tag/tag.h>
 #include "totem-gst-helpers.h"
 
 void
@@ -147,6 +148,93 @@ totem_gst_playbin_get_frame (GstElement *play)
   return pixbuf;
 }
 
+static GdkPixbuf *
+totem_gst_buffer_to_pixbuf (GstBuffer *buffer)
+{
+  GdkPixbufLoader *loader;
+  GdkPixbuf *pixbuf = NULL;
+  GError *err = NULL;
+
+  loader = gdk_pixbuf_loader_new ();
+
+  if (gdk_pixbuf_loader_write (loader, buffer->data, buffer->size, &err) &&
+      gdk_pixbuf_loader_close (loader, &err)) {
+    pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
+    if (pixbuf)
+      g_object_ref (pixbuf);
+  } else {
+    GST_WARNING("could not convert tag image to pixbuf: %s", err->message);
+    g_error_free (err);
+  }
+
+  g_object_unref (loader);
+  return pixbuf;
+}
+
+static const GValue *
+totem_gst_tag_list_get_cover_real (GstTagList *tag_list)
+{
+  const GValue *cover_value = NULL;
+  guint i;
+
+  for (i = 0; ; i++) {
+    const GValue *value;
+    GstBuffer *buffer;
+    GstStructure *caps_struct;
+    int type;
+
+    value = gst_tag_list_get_value_index (tag_list,
+					  GST_TAG_IMAGE,
+					  i);
+    if (value == NULL)
+      break;
+
+    buffer = gst_value_get_buffer (value);
+
+    caps_struct = gst_caps_get_structure (buffer->caps, 0);
+    gst_structure_get_enum (caps_struct,
+			    "image-type",
+			    GST_TYPE_TAG_IMAGE_TYPE,
+			    &type);
+    if (type == GST_TAG_IMAGE_TYPE_UNDEFINED) {
+      if (cover_value == NULL)
+        cover_value = value;
+    } else if (type == GST_TAG_IMAGE_TYPE_FRONT_COVER) {
+      cover_value = value;
+      break;
+    }
+  }
+
+  return cover_value;
+}
+
+GdkPixbuf *
+totem_gst_tag_list_get_cover (GstTagList *tag_list)
+{
+  const GValue *cover_value;
+
+  g_return_val_if_fail (tag_list != NULL, FALSE);
+
+  cover_value = totem_gst_tag_list_get_cover_real (tag_list);
+  /* Fallback to preview */
+  if (!cover_value) {
+    cover_value = gst_tag_list_get_value_index (tag_list,
+						GST_TAG_PREVIEW_IMAGE,
+						0);
+  }
+
+  if (cover_value) {
+    GstBuffer *buffer;
+    GdkPixbuf *pixbuf;
+
+    buffer = gst_value_get_buffer (cover_value);
+    pixbuf = totem_gst_buffer_to_pixbuf (buffer);
+    return pixbuf;
+  }
+
+  return NULL;
+}
+
 /*
  * vim: sw=2 ts=8 cindent noai bs=2
  */
diff --git a/src/gst/totem-gst-helpers.h b/src/gst/totem-gst-helpers.h
index aa42a40..4fe7670 100644
--- a/src/gst/totem-gst-helpers.h
+++ b/src/gst/totem-gst-helpers.h
@@ -53,6 +53,8 @@ void totem_gst_message_print (GstMessage *msg,
 
 GdkPixbuf * totem_gst_playbin_get_frame (GstElement *play);
 
+GdkPixbuf * totem_gst_tag_list_get_cover (GstTagList *tag_list);
+
 G_END_DECLS
 
 #endif				/* HAVE_TOTEM_GST_HELPERS_H */