[gimp] app: add logical operations on layer sets.

[Jehan <jehanp src gnome org>]

commit 25adf686a544260403ab3390bd68448cf05a92d2
Author: Jehan <jehan girinstud io>
Date:   Thu Feb 4 21:26:34 2021 +0100

    app: add logical operations on layer sets.

 app/core/gimpimage.c            | 96 +++++++++++++++++++++++++++++++++++++++++
 app/core/gimpimage.h            |  4 ++
 app/widgets/gimplayertreeview.c | 67 +++++++++++++++++++---------
 3 files changed, 147 insertions(+), 20 deletions(-)
---
diff --git a/app/core/gimpimage.c b/app/core/gimpimage.c
index b5f147ec40..07cca851a1 100644
--- a/app/core/gimpimage.c
+++ b/app/core/gimpimage.c
@@ -5507,6 +5507,102 @@ gimp_image_add_linked_layers (GimpImage   *image,
   g_list_free (layers);
 }
 
+/*
+ * @gimp_image_remove_linked_layers:
+ * @image:
+ * @link_name:
+ *
+ * Remove the layers belonging to the set named @link_name (which must
+ * exist) from the layers currently selected in @image.
+ *
+ * Returns: %TRUE if the selection change is done (even if it turned out
+ *          selected layers stay the same), %FALSE if no sets with this
+ *          name existed.
+ */
+void
+gimp_image_remove_linked_layers (GimpImage   *image,
+                                 const gchar *link_name)
+{
+  GimpImagePrivate *private;
+  GList            *linked;
+  GList            *layers;
+  GList            *iter;
+
+  g_return_if_fail (GIMP_IS_IMAGE (image));
+  g_return_if_fail (link_name != NULL);
+
+  private = GIMP_IMAGE_GET_PRIVATE (image);
+
+  linked = g_hash_table_lookup (private->linked_layers,
+                                link_name);
+
+  g_return_if_fail (linked);
+
+  layers = gimp_image_get_selected_layers (image);
+  layers = g_list_copy (layers);
+  for (iter = linked; iter; iter = iter->next)
+    {
+      GList *remove;
+
+      if ((remove = g_list_find (layers, iter->data)))
+        layers = g_list_delete_link (layers, remove);
+    }
+
+  gimp_image_set_selected_layers (image, layers);
+  g_list_free (layers);
+}
+
+/*
+ * @gimp_image_intersect_linked_layers:
+ * @image:
+ * @link_name:
+ *
+ * Remove any layers from the layers currently selected in @image if
+ * they don't also belong to the set named @link_name (which must
+ * exist).
+ *
+ * Returns: %TRUE if the selection change is done (even if it turned out
+ *          selected layers stay the same), %FALSE if no sets with this
+ *          name existed.
+ */
+void
+gimp_image_intersect_linked_layers (GimpImage   *image,
+                                    const gchar *link_name)
+{
+  GimpImagePrivate *private;
+  GList            *linked;
+  GList            *layers;
+  GList            *remove = NULL;
+  GList            *iter;
+
+  g_return_if_fail (GIMP_IS_IMAGE (image));
+  g_return_if_fail (link_name != NULL);
+
+  private = GIMP_IMAGE_GET_PRIVATE (image);
+
+  linked = g_hash_table_lookup (private->linked_layers,
+                                link_name);
+
+  g_return_if_fail (linked);
+
+  layers = gimp_image_get_selected_layers (image);
+  layers = g_list_copy (layers);
+
+  /* Remove items in layers but not in linked. */
+  for (iter = layers; iter; iter = iter->next)
+    {
+      if (! g_list_find (linked, iter->data))
+        remove = g_list_prepend (remove, iter);
+    }
+  for (iter = remove; iter; iter = iter->next)
+    layers = g_list_delete_link (layers, iter->data);
+  g_list_free (remove);
+
+  /* Finally select the intersection. */
+  gimp_image_set_selected_layers (image, layers);
+  g_list_free (layers);
+}
+
 /*
  * @gimp_image_get_linked_layer_names:
  * @image:
diff --git a/app/core/gimpimage.h b/app/core/gimpimage.h
index 42406f9191..07eabcdcd3 100644
--- a/app/core/gimpimage.h
+++ b/app/core/gimpimage.h
@@ -461,6 +461,10 @@ void            gimp_image_select_linked_layers  (GimpImage          *image,
                                                   const gchar        *link_name);
 void            gimp_image_add_linked_layers     (GimpImage          *image,
                                                   const gchar        *link_name);
+void            gimp_image_remove_linked_layers  (GimpImage          *image,
+                                                  const gchar        *link_name);
+void            gimp_image_intersect_linked_layers (GimpImage        *image,
+                                                    const gchar      *link_name);
 GList         * gimp_image_get_linked_layer_names (GimpImage         *image);
 
 gboolean        gimp_image_add_channel           (GimpImage          *image,
diff --git a/app/widgets/gimplayertreeview.c b/app/widgets/gimplayertreeview.c
index 91b550f1b7..5ccbb65b59 100644
--- a/app/widgets/gimplayertreeview.c
+++ b/app/widgets/gimplayertreeview.c
@@ -148,8 +148,8 @@ static void       gimp_layer_tree_view_floating_selection_changed (GimpImage
 
 static void       gimp_layer_tree_view_layer_links_changed        (GimpImage                  *image,
                                                                    GimpLayerTreeView          *view);
-static void       gimp_layer_tree_view_link_activated             (GtkListBox                 *list,
-                                                                   GtkListBoxRow               *row,
+static gboolean   gimp_layer_tree_view_link_clicked               (GtkWidget                  *box,
+                                                                   GdkEvent                   *event,
                                                                    GimpLayerTreeView          *view);
 static void       gimp_layer_tree_view_new_link_clicked           (GtkButton                  *button,
                                                                    GimpLayerTreeView          *view);
@@ -483,10 +483,6 @@ gimp_layer_tree_view_constructed (GObject *object)
 
   gtk_list_box_set_activate_on_single_click (GTK_LIST_BOX (layer_view->priv->link_list),
                                              TRUE);
-  g_signal_connect (layer_view->priv->link_list,
-                    "row-activated",
-                    G_CALLBACK (gimp_layer_tree_view_link_activated),
-                    layer_view);
 
   /* Link popover: new links. */
 
@@ -1138,8 +1134,6 @@ gimp_layer_tree_view_layer_links_changed (GimpImage         *image,
       grid = gtk_grid_new ();
 
       label = gtk_label_new (iter->data);
-      g_object_set_data (G_OBJECT (grid), "link-name",
-                         (gpointer) gtk_label_get_text (GTK_LABEL (label)));
       gtk_widget_set_hexpand (GTK_WIDGET (label), TRUE);
       gtk_widget_set_halign (GTK_WIDGET (label), GTK_ALIGN_START);
       gtk_size_group_add_widget (label_size, label);
@@ -1167,7 +1161,27 @@ gimp_layer_tree_view_layer_links_changed (GimpImage         *image,
       gtk_container_add (GTK_CONTAINER (event_box), icon);
       gtk_widget_show (icon);
 
-      gtk_list_box_prepend (GTK_LIST_BOX (view->priv->link_list), grid);
+      /* Now using again an event box on the whole grid, but behind its
+       * child (so that the delete button is processed first. I do it
+       * this way instead of using the "row-activated" of GtkListBox
+       * because this signal does not give us event info, and in
+       * particular modifier state. Yet I want to be able to process
+       * Shift/Ctrl state for logical operations on layer sets.
+       */
+      event_box = gtk_event_box_new ();
+      gtk_event_box_set_above_child (GTK_EVENT_BOX (event_box), FALSE);
+      gtk_widget_add_events (event_box, GDK_BUTTON_RELEASE_MASK);
+      g_object_set_data (G_OBJECT (event_box), "link-name",
+                         (gpointer) gtk_label_get_text (GTK_LABEL (label)));
+      gtk_container_add (GTK_CONTAINER (event_box), grid);
+      gtk_list_box_prepend (GTK_LIST_BOX (view->priv->link_list), event_box);
+      gtk_widget_show (event_box);
+
+      g_signal_connect (event_box,
+                        "button-release-event",
+                        G_CALLBACK (gimp_layer_tree_view_link_clicked),
+                        view);
+
       gtk_widget_show (grid);
     }
   g_object_unref (label_size);
@@ -1176,22 +1190,35 @@ gimp_layer_tree_view_layer_links_changed (GimpImage         *image,
   g_list_free (links);
 }
 
-static void
-gimp_layer_tree_view_link_activated (GtkListBox        *list,
-                                     GtkListBoxRow      *row,
-                                     GimpLayerTreeView *view)
+static gboolean
+gimp_layer_tree_view_link_clicked (GtkWidget         *box,
+                                   GdkEvent          *event,
+                                   GimpLayerTreeView *view)
 {
-  GimpImage *image;
-  GtkWidget *grid;
+  GimpImage       *image;
+  GdkEventButton  *bevent = (GdkEventButton *) event;
+  GdkModifierType  modifiers;
 
   image = gimp_item_tree_view_get_image (GIMP_ITEM_TREE_VIEW (view));
-  grid = gtk_bin_get_child (GTK_BIN (row));
 
-  g_return_if_fail (GIMP_IS_IMAGE (image));
-  g_return_if_fail (GTK_IS_GRID (grid));
+  g_return_val_if_fail (GIMP_IS_IMAGE (image), FALSE);
+  g_return_val_if_fail (GTK_IS_EVENT_BOX (box), FALSE);
+
+  modifiers = bevent->state & gimp_get_all_modifiers_mask ();
+  if (modifiers == GDK_SHIFT_MASK)
+    gimp_image_add_linked_layers (image,
+                                  g_object_get_data (G_OBJECT (box), "link-name"));
+  else if (modifiers == GDK_CONTROL_MASK)
+    gimp_image_remove_linked_layers (image,
+                                     g_object_get_data (G_OBJECT (box), "link-name"));
+  else if (modifiers == (GDK_CONTROL_MASK | GDK_SHIFT_MASK))
+    gimp_image_intersect_linked_layers (image,
+                                        g_object_get_data (G_OBJECT (box), "link-name"));
+  else
+    gimp_image_select_linked_layers (image,
+                                     g_object_get_data (G_OBJECT (box), "link-name"));
 
-  gimp_image_select_linked_layers (image,
-                                   g_object_get_data (G_OBJECT (grid), "link-name"));
+  return FALSE;
 }
 
 static void