playback/player: gtk-play: display cover art

We maintain two drawing widgets, image and video. Cover art is drawn in
image widget and video is rendered in video widget. Based on the following
conditions we show either image or video widget:

- if media info does not have active video stream then hide video widget
  and show image widget.
- if media info contains active video stream then show video widget and
  hide the image widget.

playback/player/gtk/gtk-play.c

@@ -22,7 +22,9 @@
 #include <string.h>
 
 #include <gst/gst.h>
+#include <gst/tag/tag.h>
 #include <gst/video/videooverlay.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
 
 #include <gdk/gdk.h>
 #if defined (GDK_WINDOWING_X11)
@@ -52,9 +54,11 @@ typedef struct
   GtkWidget *prev_button, *next_button;
   GtkWidget *seekbar;
   GtkWidget *video_area;
+  GtkWidget *image_area;
   GtkWidget *volume_button;
   GtkWidget *media_info_button;
   gulong seekbar_value_changed_signal_id;
+  GdkPixbuf *image_pixbuf;
   gboolean playing;
 } GtkPlay;
 
@@ -86,6 +90,8 @@ enum
   SUBTITLE_INFO_END,
 };
 
+static void display_cover_art (GtkPlay * play, GstPlayerMediaInfo * media_info);
+
 static void
 set_title (GtkPlay * play, const gchar * title)
 {
@@ -159,6 +165,9 @@ skip_prev_clicked_cb (GtkButton * button, GtkPlay * play)
   prev = g_list_previous (play->current_uri);
   g_return_if_fail (prev != NULL);
 
+  if (play->image_pixbuf)
+    g_object_unref (play->image_pixbuf);
+  play->image_pixbuf = NULL;
   gtk_widget_set_sensitive (play->next_button, TRUE);
   gtk_widget_set_sensitive (play->media_info_button, FALSE);
   gst_player_set_uri (play->player, prev->data);
@@ -177,6 +186,9 @@ skip_next_clicked_cb (GtkButton * button, GtkPlay * play)
   next = g_list_next (play->current_uri);
   g_return_if_fail (next != NULL);
 
+  if (play->image_pixbuf)
+    g_object_unref (play->image_pixbuf);
+  play->image_pixbuf = NULL;
   gtk_widget_set_sensitive (play->prev_button, TRUE);
   gtk_widget_set_sensitive (play->media_info_button, FALSE);
   gst_player_set_uri (play->player, next->data);
@@ -583,8 +595,10 @@ get_menu_label (GstPlayerStreamInfo * stream, GType type)
 static void
 disable_track (GtkPlay * play, GType type)
 {
-  if (type == GST_TYPE_PLAYER_VIDEO_INFO)
+  if (type == GST_TYPE_PLAYER_VIDEO_INFO) {
     gst_player_set_video_track_enabled (play->player, FALSE);
+    display_cover_art (play, NULL);  /* display cover art */
+  }
   else if (type == GST_TYPE_PLAYER_AUDIO_INFO)
     gst_player_set_audio_track_enabled (play->player, FALSE);
   else
@@ -597,6 +611,11 @@ change_track (GtkPlay * play, gint index, GType type)
   if (type == GST_TYPE_PLAYER_VIDEO_INFO) {
     gst_player_set_video_track (play->player, index);
     gst_player_set_video_track_enabled (play->player, TRUE);
+    /* if video area widget is not visible then make it visible */
+    if (!gtk_widget_is_visible (play->video_area)) {
+      gtk_widget_hide (play->image_area);
+      gtk_widget_show (play->video_area);
+    }
   } else if (type == GST_TYPE_PLAYER_AUDIO_INFO) {
     gst_player_set_audio_track (play->player, index);
     gst_player_set_audio_track_enabled (play->player, TRUE);
@@ -749,6 +768,50 @@ mouse_button_pressed_cb (GtkWidget * unused, GdkEventButton * event,
   gtk_player_popup_menu_create (play, event);
 }
 
+static gboolean
+image_area_draw_cb (GtkWidget * widget, cairo_t * cr, GtkPlay * play)
+{
+  if (play->image_pixbuf) {
+    gint width, height;
+    gint pix_width, pix_height;
+    gint x = 0, y = 0;
+    gdouble scalex = 0.0, scaley = 0.0;
+
+    width = gtk_widget_get_allocated_width (widget);
+    height = gtk_widget_get_allocated_height (widget);
+    pix_width = gdk_pixbuf_get_width (play->image_pixbuf);
+    pix_height = gdk_pixbuf_get_height (play->image_pixbuf);
+
+    /* if image is bigger than widget then scale down otherwise center it. */
+    if (width <= pix_width)
+      scalex = (gdouble)width / (gdouble)pix_width;
+    else
+      x = (width - pix_width) / 2;
+    if (height <= pix_height)
+      scaley = (gdouble)height / (gdouble)pix_height;
+    else
+      y = (height - pix_height) / 2;
+
+    /* fill background with black */
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_rectangle (cr, 0, 0, width, height);
+    cairo_fill (cr);
+
+    if (scalex > 0.0 && scaley > 0.0)
+       cairo_scale (cr, scalex, scaley);
+
+    gdk_cairo_set_source_pixbuf(cr, play->image_pixbuf, x, y);
+    cairo_paint (cr);
+  } else {
+    /* fill background with black */
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_paint (cr);
+  }
+
+  return FALSE;
+}
+
+
 static void
 create_ui (GtkPlay * play)
 {
@@ -769,6 +832,17 @@ create_ui (GtkPlay * play)
       | GDK_BUTTON_PRESS_MASK
       | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK);
 
+  play->image_area = gtk_drawing_area_new ();
+  g_signal_connect (play->image_area, "button-press-event",
+      G_CALLBACK (mouse_button_pressed_cb), play);
+  g_signal_connect (play->image_area, "draw",
+      G_CALLBACK (image_area_draw_cb), play);
+  gtk_widget_set_events (play->image_area, GDK_EXPOSURE_MASK
+        | GDK_LEAVE_NOTIFY_MASK
+        | GDK_BUTTON_PRESS_MASK
+        | GDK_POINTER_MOTION_MASK
+        | GDK_POINTER_MOTION_HINT_MASK);
+
   /* Unified play/pause button */
   play->play_pause_button =
       gtk_button_new_from_icon_name ("media-playback-pause",
@@ -825,6 +899,7 @@ create_ui (GtkPlay * play)
 
   main_hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 0);
   gtk_box_pack_start (GTK_BOX (main_hbox), play->video_area, TRUE, TRUE, 0);
+  gtk_box_pack_start (GTK_BOX (main_hbox), play->image_area, TRUE, TRUE, 0);
 
   main_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
   gtk_box_pack_start (GTK_BOX (main_vbox), main_hbox, TRUE, TRUE, 0);
@@ -832,6 +907,7 @@ create_ui (GtkPlay * play)
   gtk_container_add (GTK_CONTAINER (play->window), main_vbox);
 
   gtk_widget_realize (play->video_area);
+  gtk_widget_hide (play->video_area);
 
   gtk_widget_show_all (play->window);
 }
@@ -873,6 +949,9 @@ eos_cb (GstPlayer * unused, GtkPlay * play)
       if (!gtk_widget_is_sensitive (play->prev_button))
         gtk_widget_set_sensitive (play->prev_button, TRUE);
       gtk_widget_set_sensitive (play->next_button, g_list_next (next) != NULL);
+      if (play->image_pixbuf)
+        g_object_unref (play->image_pixbuf);
+      play->image_pixbuf = NULL;
 
       gtk_widget_set_sensitive (play->media_info_button, FALSE);
 
@@ -893,6 +972,116 @@ eos_cb (GstPlayer * unused, GtkPlay * play)
   }
 }
 
+static gboolean
+_has_active_stream (GtkPlay * play, void * (*func) (GstPlayer * player))
+{
+  void *obj;
+
+  obj = func (play->player);
+  if (obj) {
+    g_object_unref (obj);
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+static GdkPixbuf *
+gst_sample_to_pixbuf (GtkPlay * play, GstSample * sample)
+{
+  GdkPixbufLoader *loader;
+  GdkPixbuf *pixbuf = NULL;
+  GError *err = NULL;
+  GstMapInfo info;
+  GstBuffer *buffer;
+  const GstStructure *caps_struct;
+  GstTagImageType type = GST_TAG_IMAGE_TYPE_UNDEFINED;
+
+  buffer = gst_sample_get_buffer (sample);
+  caps_struct = gst_sample_get_info (sample);
+
+  /* if sample is retrieved from preview-image tag then caps struct
+   * will not be defined. */
+  if (caps_struct)
+    gst_structure_get_enum (caps_struct, "image-type",
+        GST_TYPE_TAG_IMAGE_TYPE, &type);
+
+  /* FIXME: Should we check more type ?? */
+  if ((type != GST_TAG_IMAGE_TYPE_FRONT_COVER) &&
+      (type != GST_TAG_IMAGE_TYPE_UNDEFINED) &&
+      (type != GST_TAG_IMAGE_TYPE_NONE)) {
+    g_print ("unsupport type ... %d \n", type);
+    return NULL;
+  }
+
+  if (!gst_buffer_map (buffer, &info, GST_MAP_READ)) {
+    g_print ("failed to map gst buffer \n");
+    return NULL;
+  }
+
+  loader = gdk_pixbuf_loader_new ();
+  if (gdk_pixbuf_loader_write (loader, info.data, info.size, &err) &&
+      gdk_pixbuf_loader_close (loader, &err)) {
+    pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
+    if (pixbuf) {
+      g_object_ref (pixbuf);
+    }
+    else {
+      g_print ("failed to convert gst buffer to pixbuf %s \n", err->message);
+      g_error_free (err);
+    }
+  }
+
+  g_object_unref (loader);
+  gst_buffer_unmap (buffer, &info);
+
+  return pixbuf;
+}
+
+static void
+display_cover_art (GtkPlay * play, GstPlayerMediaInfo * media_info)
+{
+  GstSample *sample;
+  GstPlayerMediaInfo *temp_media_info = NULL;
+
+  /* hide the video widget and show image widget */
+  gtk_widget_hide (play->video_area);
+  gtk_widget_show (play->image_area);
+
+  /* if media information is not passed then get it from player */
+  if (!media_info)
+    temp_media_info = media_info = gst_player_get_media_info (play->player);
+
+  sample = gst_player_media_info_get_image_sample (media_info);
+  if (!sample)
+    goto cleanup;
+
+  if (play->image_pixbuf)
+    g_object_unref (play->image_pixbuf);
+
+  play->image_pixbuf = gst_sample_to_pixbuf (play, sample);
+
+cleanup:
+  gtk_widget_queue_draw (play->image_area); /* send expose event to widget */
+
+  if (temp_media_info)
+    g_object_unref (temp_media_info);
+}
+
+static gboolean
+has_active_stream (GtkPlay * play, GType type)
+{
+  if (type == GST_TYPE_PLAYER_VIDEO_INFO)
+    return _has_active_stream (play,
+        (void *) gst_player_get_current_video_track);
+  else if (type == GST_TYPE_PLAYER_AUDIO_INFO)
+    return _has_active_stream (play,
+        (void *) gst_player_get_current_audio_track);
+  else
+    return _has_active_stream (play,
+        (void *) gst_player_get_current_subtitle_track);
+}
+
 static void
 media_info_updated_cb (GstPlayer * player, GstPlayerMediaInfo * media_info,
     GtkPlay * play)
@@ -905,6 +1094,16 @@ media_info_updated_cb (GstPlayer * player, GstPlayerMediaInfo * media_info,
       set_title (play, title);
 
     gtk_widget_set_sensitive (play->media_info_button, TRUE);
+
+    /* if we have active video stream then hide image widget
+     * and show video widget otherwise show the cover art.
+     */
+    if (has_active_stream (play, GST_TYPE_PLAYER_VIDEO_INFO)) {
+      gtk_widget_hide (play->image_area);
+      gtk_widget_show (play->video_area);
+    } else {
+      display_cover_art (play, media_info);
+    }
   }
 }