From d405ac8a358919ce95c449924ddfe66a8cf68ecd Mon Sep 17 00:00:00 2001
From: Simon Steinbeiss <simon.steinbeiss@elfenbeinturm.at>
Date: Wed, 26 Jun 2019 00:17:47 +0200
Subject: [PATCH] tasklist: Add fallback for missing window icons (Bug #15511)

While libwnck provides icons, we can - as final fallback - also query
the name of the WM_CLASS property of the window and look for an icon of
that name in the icon theme.
---
 plugins/tasklist/tasklist-widget.c | 43 +++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/plugins/tasklist/tasklist-widget.c b/plugins/tasklist/tasklist-widget.c
index 296093ee..33f46d92 100644
--- a/plugins/tasklist/tasklist-widget.c
+++ b/plugins/tasklist/tasklist-widget.c
@@ -616,7 +616,39 @@ xfce_tasklist_init (XfceTasklist *tasklist)
   gtk_widget_show (tasklist->arrow_button);
 }
 
+static GdkPixbuf *
+xfce_tasklist_get_window_icon (WnckWindow *window,
+                               gboolean show_labels,
+                               int size,
+                               int type)
+{
+  GdkPixbuf *pixbuf;
 
+  if (show_labels || type == CHILD_TYPE_GROUP_MENU)
+    pixbuf = wnck_window_get_mini_icon (window);
+  else if (size <= 31)
+    pixbuf = wnck_window_get_mini_icon (window);
+  else
+    pixbuf = wnck_window_get_icon (window);
+
+  /* Fallback: Get the pixbuf from the icon theme, and also avoid
+   * overwriting `pixbuf' because if it holds a valid fallback
+   * icon then it can become `NULL' after this call leading
+   * to no icon at all to render */
+  if (!pixbuf || wnck_window_get_icon_is_fallback (window))
+    {
+      GdkPixbuf  *themed_icon;
+      const char *name;
+
+      name = wnck_window_get_class_instance_name (window);
+      themed_icon = gtk_icon_theme_load_icon (gtk_icon_theme_get_default (), name, size,
+                                              GTK_ICON_LOOKUP_FORCE_SIZE, NULL);
+      if (themed_icon)
+        pixbuf = gdk_pixbuf_copy (themed_icon);
+    }
+
+  return pixbuf;
+}
 
 static void
 xfce_tasklist_get_property (GObject    *object,
@@ -2553,14 +2585,7 @@ xfce_tasklist_button_icon_changed (WnckWindow        *window,
   context = gtk_widget_get_style_context (GTK_WIDGET (child->icon));
 
   /* get the window icon */
-  if (tasklist->show_labels ||
-      child->type == CHILD_TYPE_GROUP_MENU)
-    pixbuf = wnck_window_get_mini_icon (window);
-  else if (icon_size <= 31)
-    pixbuf = wnck_window_get_mini_icon (window);
-  else
-    pixbuf = wnck_window_get_icon (window);
-
+  pixbuf = xfce_tasklist_get_window_icon (child->window, tasklist->show_labels, icon_size, child->type);
   /* leave when there is no valid pixbuf */
   if (G_UNLIKELY (pixbuf == NULL))
     {
@@ -3264,7 +3289,7 @@ xfce_tasklist_button_drag_begin (GtkWidget         *button,
     }
 #endif
 
-  pixbuf = wnck_window_get_icon (child->window);
+  pixbuf = xfce_tasklist_get_window_icon (child->window, FALSE, 32, CHILD_TYPE_WINDOW);
   if (G_LIKELY (pixbuf != NULL))
     gtk_drag_set_icon_pixbuf (context, pixbuf, 0, 0);
 }
-- 
2.19.1