Merge branch 'wip/corey/tree-expander' into 'main'

treeexpander: Add hide-expander and indent-for-depth properties

Closes #4969

See merge request GNOME/gtk!5268

2 files changed, 186 insertions, 33 deletions

diff --git a/gtk/gtktreeexpander.c b/gtk/gtktreeexpander.c
index ef40403938..cad8c8d8d0 100644
--- a/gtk/gtktreeexpander.c
+++ b/gtk/gtktreeexpander.c
@@ -52,6 +52,13 @@
  * [method@Gtk.TreeExpander.set_child] sets the widget that displays
  * the actual row contents.
  *
+ * `GtkTreeExpander` can be modified with properties such as [property@Gtk.indent-for-icon],
+ * [property@Gtk.indent-for-depth], and [property@Gtk.hide-expander] to achieve a
+ * different appearance. This can even be done to influence individual rows, for example
+ * by binding the [property@Gtk.hide-expander] property to the treelistrow's model's
+ * item count to hide the expander for rows without children, even if the row is
+ * expandable.
+ *
  * # CSS nodes
  *
  * ```
@@ -85,6 +92,8 @@ struct _GtkTreeExpander
   GtkWidget *expander_icon;
   guint notify_handler;
 
+  gboolean hide_expander;
+  gboolean indent_for_depth;
   gboolean indent_for_icon;
 
   guint expand_timer;
@@ -94,9 +103,11 @@ enum
 {
   PROP_0,
   PROP_CHILD,
+  PROP_HIDE_EXPANDER,
+  PROP_INDENT_FOR_DEPTH,
+  PROP_INDENT_FOR_ICON,
   PROP_ITEM,
   PROP_LIST_ROW,
-  PROP_INDENT_FOR_ICON,
 
   N_PROPS
 };
@@ -169,8 +180,8 @@ gtk_tree_expander_update_for_list_row (GtkTreeExpander *self)
       GtkWidget *child;
       guint i, depth;
 
-      depth = gtk_tree_list_row_get_depth (self->list_row);
-      if (gtk_tree_list_row_is_expandable (self->list_row))
+      depth = self->indent_for_depth ? gtk_tree_list_row_get_depth (self->list_row) : 0;
+      if (gtk_tree_list_row_is_expandable (self->list_row) && !self->hide_expander)
         {
           if (self->expander_icon == NULL)
             {
@@ -394,18 +405,26 @@ gtk_tree_expander_get_property (GObject    *object,
       g_value_set_object (value, self->child);
       break;
 
-    case PROP_ITEM:
-      g_value_take_object (value, gtk_tree_expander_get_item (self));
+    case PROP_HIDE_EXPANDER:
+      g_value_set_boolean (value, gtk_tree_expander_get_hide_expander (self));
       break;
 
-    case PROP_LIST_ROW:
-      g_value_set_object (value, self->list_row);
+    case PROP_INDENT_FOR_DEPTH:
+      g_value_set_boolean (value, gtk_tree_expander_get_indent_for_depth (self));
       break;
 
     case PROP_INDENT_FOR_ICON:
       g_value_set_boolean (value, gtk_tree_expander_get_indent_for_icon (self));
       break;
 
+    case PROP_ITEM:
+      g_value_take_object (value, gtk_tree_expander_get_item (self));
+      break;
+
+    case PROP_LIST_ROW:
+      g_value_set_object (value, self->list_row);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -426,14 +445,22 @@ gtk_tree_expander_set_property (GObject      *object,
       gtk_tree_expander_set_child (self, g_value_get_object (value));
       break;
 
-    case PROP_LIST_ROW:
-      gtk_tree_expander_set_list_row (self, g_value_get_object (value));
+    case PROP_HIDE_EXPANDER:
+      gtk_tree_expander_set_hide_expander (self, g_value_get_boolean (value));
+      break;
+
+    case PROP_INDENT_FOR_DEPTH:
+      gtk_tree_expander_set_indent_for_depth (self, g_value_get_boolean (value));
       break;
 
     case PROP_INDENT_FOR_ICON:
       gtk_tree_expander_set_indent_for_icon (self, g_value_get_boolean (value));
       break;
 
+    case PROP_LIST_ROW:
+      gtk_tree_expander_set_list_row (self, g_value_get_object (value));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -533,24 +560,33 @@ gtk_tree_expander_class_init (GtkTreeExpanderClass *klass)
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
 
   /**
-   * GtkTreeExpander:item: (attributes org.gtk.Property.get=gtk_tree_expander_get_item)
+   * GtkTreeExpander:hide-expander: (attributes org.gtk.Property.get=gtk_tree_expander_get_hide_expander org.gtk.Property.set=gtk_tree_expander_set_hide_expander)
    *
-   * The item held by this expander's row.
+   * Whether the expander icon should be hidden in a GtkTreeListRow.
+   * Note that this property simply hides the icon.  The actions and keybinding
+   * (i.e. collapse and expand) are not affected by this property.
+   *
+   * A common use for this property would be to bind to the number of children in a
+   * GtkTreeListRow's model in order to hide the expander when a row has no children.
+   *
+   * Since: 4.10
    */
-  properties[PROP_ITEM] =
-      g_param_spec_object ("item", NULL, NULL,
-                           G_TYPE_OBJECT,
-                           G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+  properties[PROP_HIDE_EXPANDER] =
+      g_param_spec_boolean ("hide-expander", NULL, NULL,
+                            FALSE,
+                            G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
   /**
-   * GtkTreeExpander:list-row: (attributes org.gtk.Property.get=gtk_tree_expander_get_list_row org.gtk.Property.set=gtk_tree_expander_set_list_row)
+   * GtkTreeExpander:indent-for-depth: (attributes org.gtk.Property.get=gtk_tree_expander_get_indent_for_depth org.gtk.Property.set=gtk_tree_expander_set_indent_for_depth)
    *
-   * The list row to track for expander state.
+   * TreeExpander indents the child according to its depth.
+   *
+   * Since: 4.10
    */
-  properties[PROP_LIST_ROW] =
-    g_param_spec_object ("list-row", NULL, NULL,
-                         GTK_TYPE_TREE_LIST_ROW,
-                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+  properties[PROP_INDENT_FOR_DEPTH] =
+      g_param_spec_boolean ("indent-for-depth", NULL, NULL,
+                            TRUE,
+                            G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
   /**
    * GtkTreeExpander:indent-for-icon: (attributes org.gtk.Property.get=gtk_tree_expander_get_indent_for_icon org.gtk.Property.set=gtk_tree_expander_set_indent_for_icon)
@@ -564,6 +600,26 @@ gtk_tree_expander_class_init (GtkTreeExpanderClass *klass)
                             TRUE,
                             G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
+  /**
+   * GtkTreeExpander:item: (attributes org.gtk.Property.get=gtk_tree_expander_get_item)
+   *
+   * The item held by this expander's row.
+   */
+  properties[PROP_ITEM] =
+      g_param_spec_object ("item", NULL, NULL,
+                           G_TYPE_OBJECT,
+                           G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * GtkTreeExpander:list-row: (attributes org.gtk.Property.get=gtk_tree_expander_get_list_row org.gtk.Property.set=gtk_tree_expander_set_list_row)
+   *
+   * The list row to track for expander state.
+   */
+  properties[PROP_LIST_ROW] =
+    g_param_spec_object ("list-row", NULL, NULL,
+                         GTK_TYPE_TREE_LIST_ROW,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (gobject_class, N_PROPS, properties);
 
   /**
@@ -697,6 +753,7 @@ gtk_tree_expander_init (GtkTreeExpander *self)
 
   gtk_widget_set_focusable (GTK_WIDGET (self), TRUE);
   self->indent_for_icon = TRUE;
+  self->indent_for_depth = TRUE;
 
   controller = gtk_drop_controller_motion_new ();
   g_signal_connect (controller, "enter", G_CALLBACK (gtk_tree_expander_drag_enter), self);
@@ -850,6 +907,49 @@ gtk_tree_expander_set_list_row (GtkTreeExpander *self,
 }
 
 /**
+ * gtk_tree_expander_get_indent_for_depth: (attributes org.gtk.Method.get_property=indent-for-depth)
+ * @self: a `GtkTreeExpander`
+ *
+ * TreeExpander indents each level of depth with an additional indent.
+ *
+ * Returns: TRUE if the child should be indented . Otherwise FALSE.
+ *
+ * Since: 4.10
+ */
+gboolean
+gtk_tree_expander_get_indent_for_depth (GtkTreeExpander *self)
+{
+  g_return_val_if_fail (GTK_IS_TREE_EXPANDER (self), FALSE);
+
+  return self->indent_for_depth;
+}
+
+/**
+ * gtk_tree_expander_set_indent_for_depth: (attributes org.gtk.Method.set_property=indent-for-depth)
+ * @self: a `GtkTreeExpander` widget
+ * @indent_for_depth: TRUE if the child should be indented. Otherwise FALSE.
+ *
+ * Sets if the TreeExpander should indent the child according to its depth.
+ *
+ * Since: 4.10
+ */
+void
+gtk_tree_expander_set_indent_for_depth (GtkTreeExpander *self,
+                                        gboolean         indent_for_depth)
+{
+  g_return_if_fail (GTK_IS_TREE_EXPANDER (self));
+
+  if (indent_for_depth == self->indent_for_depth)
+    return;
+
+  self->indent_for_depth = indent_for_depth;
+
+  gtk_tree_expander_update_for_list_row (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_INDENT_FOR_DEPTH]);
+}
+
+/**
  * gtk_tree_expander_get_indent_for_icon: (attributes org.gtk.Method.get_property=indent-for-icon)
  * @self: a `GtkTreeExpander`
  *
@@ -878,7 +978,7 @@ gtk_tree_expander_get_indent_for_icon (GtkTreeExpander *self)
  */
 void
 gtk_tree_expander_set_indent_for_icon (GtkTreeExpander *self,
-                                       gboolean indent_for_icon)
+                                       gboolean         indent_for_icon)
 {
   g_return_if_fail (GTK_IS_TREE_EXPANDER (self));
 
@@ -891,3 +991,46 @@ gtk_tree_expander_set_indent_for_icon (GtkTreeExpander *self,
 
   g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_INDENT_FOR_ICON]);
 }
+
+/**
+ * gtk_tree_expander_get_hide_expander: (attributes org.gtk.Method.get_property=hide-expander)
+ * @self: a `GtkTreeExpander`
+ *
+ * Gets whether the TreeExpander should be hidden in a GtkTreeListRow.
+ *
+ * Returns: TRUE if the expander icon should be hidden. Otherwise FALSE.
+ *
+ * Since: 4.10
+ */
+gboolean
+gtk_tree_expander_get_hide_expander (GtkTreeExpander *self)
+{
+  g_return_val_if_fail (GTK_IS_TREE_EXPANDER (self), FALSE);
+
+  return self->hide_expander;
+}
+
+/**
+ * gtk_tree_expander_set_hide_expander: (attributes org.gtk.Method.set_property=hide-expander)
+ * @self: a `GtkTreeExpander` widget
+ * @hide_expander: TRUE if the expander should be hidden. Otherwise FALSE.
+ *
+ * Sets whether the expander icon should be visible in a GtkTreeListRow.
+ *
+ * Since: 4.10
+ */
+void
+gtk_tree_expander_set_hide_expander (GtkTreeExpander *self,
+                                     gboolean         hide_expander)
+{
+  g_return_if_fail (GTK_IS_TREE_EXPANDER (self));
+
+  if (hide_expander == self->hide_expander)
+    return;
+
+  self->hide_expander = hide_expander;
+
+  gtk_tree_expander_update_for_list_row (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HIDE_EXPANDER]);
+}
diff --git a/gtk/gtktreeexpander.h b/gtk/gtktreeexpander.h
index eec33f091f..bb4db67a4a 100644
--- a/gtk/gtktreeexpander.h
+++ b/gtk/gtktreeexpander.h
@@ -35,26 +35,36 @@ GDK_AVAILABLE_IN_ALL
 G_DECLARE_FINAL_TYPE (GtkTreeExpander, gtk_tree_expander, GTK, TREE_EXPANDER, GtkWidget)
 
 GDK_AVAILABLE_IN_ALL
-GtkWidget *             gtk_tree_expander_new                 (void);
+GtkWidget *             gtk_tree_expander_new                  (void);
 
 GDK_AVAILABLE_IN_ALL
-GtkWidget *             gtk_tree_expander_get_child           (GtkTreeExpander        *self);
+GtkWidget *             gtk_tree_expander_get_child            (GtkTreeExpander        *self);
 GDK_AVAILABLE_IN_ALL
-void                    gtk_tree_expander_set_child           (GtkTreeExpander        *self,
-                                                               GtkWidget              *child);
+void                    gtk_tree_expander_set_child            (GtkTreeExpander        *self,
+                                                                GtkWidget              *child);
 
 GDK_AVAILABLE_IN_ALL
-gpointer                gtk_tree_expander_get_item            (GtkTreeExpander        *self);
+gpointer                gtk_tree_expander_get_item             (GtkTreeExpander        *self);
 GDK_AVAILABLE_IN_ALL
-GtkTreeListRow *        gtk_tree_expander_get_list_row        (GtkTreeExpander        *self);
+GtkTreeListRow *        gtk_tree_expander_get_list_row         (GtkTreeExpander        *self);
 GDK_AVAILABLE_IN_ALL
-void                    gtk_tree_expander_set_list_row        (GtkTreeExpander        *self,
-                                                               GtkTreeListRow         *list_row);
+void                    gtk_tree_expander_set_list_row         (GtkTreeExpander        *self,
+                                                                GtkTreeListRow         *list_row);
+GDK_AVAILABLE_IN_4_10
+gboolean                gtk_tree_expander_get_indent_for_depth (GtkTreeExpander        *self);
+GDK_AVAILABLE_IN_4_10
+void                    gtk_tree_expander_set_indent_for_depth (GtkTreeExpander        *self,
+                                                                gboolean                indent_for_depth);
 GDK_AVAILABLE_IN_4_6
-gboolean                gtk_tree_expander_get_indent_for_icon (GtkTreeExpander        *self);
+gboolean                gtk_tree_expander_get_indent_for_icon  (GtkTreeExpander        *self);
 GDK_AVAILABLE_IN_4_6
-void                    gtk_tree_expander_set_indent_for_icon (GtkTreeExpander        *self,
-                                                               gboolean               indent_for_icon);
+void                    gtk_tree_expander_set_indent_for_icon  (GtkTreeExpander        *self,
+                                                                gboolean               indent_for_icon);
+GDK_AVAILABLE_IN_4_10
+gboolean                gtk_tree_expander_get_hide_expander    (GtkTreeExpander        *self);
+GDK_AVAILABLE_IN_4_10
+void                    gtk_tree_expander_set_hide_expander    (GtkTreeExpander        *self,
+                                                                gboolean                hide_expander);
 
 G_END_DECLS