GtkOverlay as GtkBuildable

The GtkOverlay implementation of the GtkBuildable interface supports placing a child as an overlay by specifying “overlay” as the “type” attribute of a <child> element.

CSS nodes

GtkOverlay has a single CSS node with the name “overlay”. Overlay children whose alignments cause them to be positioned at an edge get the style classes “.left”, “.right”, “.top”, and/or “.bottom” according to their position.

gtk_overlay_new ()

GtkWidget *
gtk_overlay_new (void);

Creates a new GtkOverlay.

Since: 3.2

gtk_overlay_add_overlay ()

void
gtk_overlay_add_overlay (GtkOverlay *overlay,
                         GtkWidget *widget);

Adds widget to overlay .

The widget will be stacked on top of the main widget added with gtk_container_add().

The position at which widget is placed is determined from its “halign” and “valign” properties.

Since: 3.2

gtk_overlay_reorder_overlay ()

void
gtk_overlay_reorder_overlay (GtkOverlay *overlay,
                             GtkWidget *child,
                             int index_);

Moves child to a new index in the list of overlay children. The list contains overlays in the order that these were added to overlay by default. See also “index”.

A widget’s index in the overlay children list determines which order the children are drawn if they overlap. The first child is drawn at the bottom. It also affects the default focus chain order.

Since: 3.18

gtk_overlay_get_overlay_pass_through ()

gboolean
gtk_overlay_get_overlay_pass_through (GtkOverlay *overlay,
                                      GtkWidget *widget);

Convenience function to get the value of the “pass-through” child property for widget .

Since: 3.18

gtk_overlay_set_overlay_pass_through ()

void
gtk_overlay_set_overlay_pass_through (GtkOverlay *overlay,
                                      GtkWidget *widget,
                                      gboolean pass_through);

Convenience function to set the value of the “pass-through” child property for widget .

Since: 3.18

struct GtkOverlay

struct GtkOverlay;

struct GtkOverlayClass

struct GtkOverlayClass {
  GtkBinClass parent_class;

  gboolean (*get_child_position) (GtkOverlay    *overlay,
                                  GtkWidget     *widget,
                                  GtkAllocation *allocation);
};

The “index” child property

  “index”                    int

The index of the overlay child in the parent (or -1 for the main child). See gtk_overlay_reorder_overlay().

Owner: GtkOverlay

Flags: Read / Write

Allowed values: >= -1

Default value: 0

Since: 3.18

The “pass-through” child property

  “pass-through”             gboolean

Whether to pass input through the overlay child to the main child. (Of course, this has no effect when set on the main child itself.)

Note that this is implemented by calling gdk_window_set_pass_through() on the window that the overlay child is placed in. If the descendents of the overlay child have their own windows, you need to manually call that function on them to achieve the desired effect.

Owner: GtkOverlay

Flags: Read / Write

Default value: FALSE

Since: 3.18

The “get-child-position” signal

gboolean
user_function (GtkOverlay   *overlay,
               GtkWidget    *widget,
               GdkRectangle *allocation,
               gpointer      user_data)

The ::get-child-position signal is emitted to determine the position and size of any overlay child widgets. A handler for this signal should fill allocation with the desired position and size for widget , relative to the 'main' child of overlay .

The default handler for this signal uses the widget 's halign and valign properties to determine the position and gives the widget its natural size (except that an alignment of GTK_ALIGN_FILL will cause the overlay to be full-width/height). If the main child is a GtkScrolledWindow, the overlays are placed relative to its contents.

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