app: handle visbility/excludes-backdrop changes in floating sel.

When attaching a layer as a floating selection to a drawable,
unbind its visiblility from its activeness, as per the previous
commit, and use its visibility to control the activeness of the
drawable's floating selection filter.

Properly update the drawable when the floating selection's
visibility and excludes-backdrop properties change.

app/core/gimpdrawable-floating-selection.c

@@ -41,23 +41,27 @@
 
 /*  local function prototypes  */
 
-static void    gimp_drawable_remove_fs_filter   (GimpDrawable      *drawable);
-static void    gimp_drawable_sync_fs_filter     (GimpDrawable      *drawable);
-
-static void    gimp_drawable_fs_notify          (GimpLayer         *fs,
-                                                 const GParamSpec  *pspec,
-                                                 GimpDrawable      *drawable);
-static void    gimp_drawable_fs_affect_changed  (GimpImage         *image,
-                                                 GimpChannelType    channel,
-                                                 GimpDrawable      *drawable);
-static void    gimp_drawable_fs_mask_changed    (GimpImage         *image,
-                                                 GimpDrawable      *drawable);
-static void    gimp_drawable_fs_update          (GimpLayer         *fs,
-                                                 gint               x,
-                                                 gint               y,
-                                                 gint               width,
-                                                 gint               height,
-                                                 GimpDrawable      *drawable);
+static void    gimp_drawable_remove_fs_filter             (GimpDrawable      *drawable);
+static void    gimp_drawable_sync_fs_filter               (GimpDrawable      *drawable);
+
+static void    gimp_drawable_fs_notify                    (GimpLayer         *fs,
+                                                           const GParamSpec  *pspec,
+                                                           GimpDrawable      *drawable);
+static void    gimp_drawable_fs_affect_changed            (GimpImage         *image,
+                                                           GimpChannelType    channel,
+                                                           GimpDrawable      *drawable);
+static void    gimp_drawable_fs_mask_changed              (GimpImage         *image,
+                                                           GimpDrawable      *drawable);
+static void    gimp_drawable_fs_visibility_changed        (GimpLayer         *fs,
+                                                           GimpDrawable      *drawable);
+static void    gimp_drawable_fs_excludes_backdrop_changed (GimpLayer         *fs,
+                                                           GimpDrawable      *drawable);
+static void    gimp_drawable_fs_update                    (GimpLayer         *fs,
+                                                           gint               x,
+                                                           gint               y,
+                                                           gint               width,
+                                                           gint               height,
+                                                           GimpDrawable      *drawable);
 
 
 /*  public functions  */
@@ -91,8 +95,17 @@ gimp_drawable_attach_floating_sel (GimpDrawable *drawable,
   /*  clear the selection  */
   gimp_drawable_invalidate_boundary (GIMP_DRAWABLE (fs));
 
+  gimp_item_bind_visible_to_active (GIMP_ITEM (fs), FALSE);
+  gimp_filter_set_active (GIMP_FILTER (fs), FALSE);
+
   _gimp_drawable_add_floating_sel_filter (drawable);
 
+  g_signal_connect (fs, "visibility-changed",
+                    G_CALLBACK (gimp_drawable_fs_visibility_changed),
+                    drawable);
+  g_signal_connect (fs, "excludes-backdrop-changed",
+                    G_CALLBACK (gimp_drawable_fs_excludes_backdrop_changed),
+                    drawable);
   g_signal_connect (fs, "update",
                     G_CALLBACK (gimp_drawable_fs_update),
                     drawable);
@@ -120,6 +133,12 @@ gimp_drawable_detach_floating_sel (GimpDrawable *drawable)
 
   gimp_drawable_remove_fs_filter (drawable);
 
+  g_signal_handlers_disconnect_by_func (fs,
+                                        gimp_drawable_fs_visibility_changed,
+                                        drawable);
+  g_signal_handlers_disconnect_by_func (fs,
+                                        gimp_drawable_fs_excludes_backdrop_changed,
+                                        drawable);
   g_signal_handlers_disconnect_by_func (fs,
                                         gimp_drawable_fs_update,
                                         drawable);
@@ -130,6 +149,8 @@ gimp_drawable_detach_floating_sel (GimpDrawable *drawable)
                            gimp_item_get_height (GIMP_ITEM (fs)),
                            drawable);
 
+  gimp_item_bind_visible_to_active (GIMP_ITEM (fs), TRUE);
+
   /*  clear the selection  */
   gimp_drawable_invalidate_boundary (GIMP_DRAWABLE (fs));
 
@@ -271,6 +292,9 @@ gimp_drawable_sync_fs_filter (GimpDrawable *drawable)
   gint                off_x, off_y;
   gint                fs_off_x, fs_off_y;
 
+  gimp_filter_set_active (private->fs_filter,
+                          gimp_item_get_visible (GIMP_ITEM (fs)));
+
   gimp_item_get_offset (GIMP_ITEM (drawable), &off_x, &off_y);
   gimp_item_get_offset (GIMP_ITEM (fs), &fs_off_x, &fs_off_y);
 
@@ -314,10 +338,13 @@ gimp_drawable_fs_notify (GimpLayer        *fs,
                          const GParamSpec *pspec,
                          GimpDrawable     *drawable)
 {
-  if (! strcmp (pspec->name, "offset-x") ||
-      ! strcmp (pspec->name, "offset-y") ||
-      ! strcmp (pspec->name, "visible")  ||
-      ! strcmp (pspec->name, "mode")     ||
+  if (! strcmp (pspec->name, "offset-x")        ||
+      ! strcmp (pspec->name, "offset-y")        ||
+      ! strcmp (pspec->name, "visible")         ||
+      ! strcmp (pspec->name, "mode")            ||
+      ! strcmp (pspec->name, "blend-space")     ||
+      ! strcmp (pspec->name, "composite-space") ||
+      ! strcmp (pspec->name, "composite-mode")  ||
       ! strcmp (pspec->name, "opacity"))
     {
       gimp_drawable_sync_fs_filter (drawable);
@@ -347,6 +374,24 @@ gimp_drawable_fs_mask_changed (GimpImage    *image,
   gimp_drawable_update (GIMP_DRAWABLE (fs), 0, 0, -1, -1);
 }
 
+static void
+gimp_drawable_fs_visibility_changed (GimpLayer    *fs,
+                                     GimpDrawable *drawable)
+{
+  if (gimp_layer_get_excludes_backdrop (fs))
+    gimp_drawable_update (drawable, 0, 0, -1, -1);
+  else
+    gimp_drawable_update (GIMP_DRAWABLE (fs), 0, 0, -1, -1);
+}
+
+static void
+gimp_drawable_fs_excludes_backdrop_changed (GimpLayer    *fs,
+                                            GimpDrawable *drawable)
+{
+  if (gimp_item_get_visible (GIMP_ITEM (fs)))
+    gimp_drawable_update (drawable, 0, 0, -1, -1);
+}
+
 static void
 gimp_drawable_fs_update (GimpLayer    *fs,
                          gint          x,