Class: Gtk::Overlay

Inherits:
Widget
  • Object
show all
Defined in:
(unknown)

Overview

GtkOverlay is a container which contains a single main child, on top of which it can place “overlay” widgets.

An example GtkOverlay

The position of each overlay widget is determined by its [propertyGtk.Widget:halign] and [propertyGtk.Widget:valign] properties. E.g. a widget with both alignments set to %GTK_ALIGN_START will be placed at the top left corner of the GtkOverlay container, whereas an overlay with halign set to %GTK_ALIGN_CENTER and valign set to %GTK_ALIGN_END will be placed a the bottom edge of the GtkOverlay, horizontally centered. The position can be adjusted by setting the margin properties of the child to non-zero values.

More complicated placement of overlays is possible by connecting to the [signalGtk.Overlay::get-child-position] signal.

An overlay’s minimum and natural sizes are those of its main child. The sizes of overlay children are not considered when measuring these preferred sizes.

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.

Instance Method Summary collapse

Methods inherited from Widget

#accessible_role, #accessible_role=, #action_set_enabled, #activate, #activate_action, #activate_action_variant, #activate_default, #activate_signal, #activate_signal=, #activate_signal_from_name=, #add_binding, #add_binding_action, #add_binding_signal, #add_controller, #add_css_class, #add_mnemonic_label, #add_shortcut, #add_tick_callback, #allocate, #allocated_baseline, #allocated_height, #allocated_width, #baseline, #bind_template_callback_full, #bind_template_child_full, #can_focus, #can_focus=, #can_focus?, #can_target, #can_target=, #can_target?, #child_focus, #child_visible, #child_visible=, #clipboard, #compute_bounds, #compute_expand, #compute_point, #compute_transform, #contains, #create_pango_context, #create_pango_layout, #css_classes, #css_classes=, #css_name, #css_name=, #cursor, #cursor=, #cursor_from_name=, default_direction, default_direction=, #direction, #direction=, #display, #dispose_template, #drag_check_threshold, #error_bell, #first_child, #focus_child, #focus_child=, #focus_on_click, #focus_on_click=, #focus_on_click?, #focusable, #focusable=, #focusable?, #font_map, #font_map=, #font_options, #font_options=, #frame_clock, #get_allocation, #get_ancestor, #get_color, #get_preferred_size, #get_size, #get_size_request, #get_template_child, #grab_focus, #halign, #halign=, #has_css_class, #has_default, #has_default=, #has_default?, #has_focus, #has_focus=, #has_focus?, #has_tooltip, #has_tooltip=, #has_tooltip?, #has_visible_focus, #height, #height_request, #height_request=, #hexpand, #hexpand=, #hexpand?, #hexpand_set, #hexpand_set=, #hexpand_set?, #hide, #in_destruction, #init_template, #insert_action_group, #insert_after, #insert_before, #install_action, #install_property_action, #is_ancestor, #is_drawable, #is_focus, #is_sensitive, #is_visible, #keynav_failed, #last_child, #layout_manager, #layout_manager=, #layout_manager_type, #layout_manager_type=, #list_mnemonic_labels, #map, #mapped, #margin_bottom, #margin_bottom=, #margin_end, #margin_end=, #margin_start, #margin_start=, #margin_top, #margin_top=, #measure, #mnemonic_activate, #name, #name=, #native, #next_sibling, #observe_children, #observe_controllers, #opacity, #opacity=, #overflow, #overflow=, #pango_context, #parent, #parent=, #pick, #prev_sibling, #primary_clipboard, #query_action, #queue_allocate, #queue_draw, #queue_resize, #realize, #realized, #receives_default, #receives_default=, #receives_default?, #remove_controller, #remove_css_class, #remove_mnemonic_label, #remove_tick_callback, #request_mode, #root, #root=, #scale_factor, #scale_factor=, #sensitive, #sensitive=, #sensitive?, #set_size_request, #set_state_flags, #settings, #should_layout, #show, #size_allocate, #snapshot_child, #state_flags, #style_context, #template=, #template_from_resource=, #template_scope=, #tooltip_markup, #tooltip_markup=, #tooltip_text, #tooltip_text=, #translate_coordinates, #trigger_tooltip_query, #unmap, #unparent, #unrealize, #unset_state_flags, #valign, #valign=, #vexpand, #vexpand=, #vexpand?, #vexpand_set, #vexpand_set=, #vexpand_set?, #visible, #visible=, #visible?, #width, #width_request, #width_request=

Constructor Details

#initializeGtk::Widget

Creates a new GtkOverlay.

Instance Method Details

#add_overlay(widget) ⇒ nil

Adds widget to overlay.

The widget will be stacked on top of the main widget added with [methodGtk.Overlay.set_child].

The position at which widget is placed is determined from its [propertyGtk.Widget:halign] and [propertyGtk.Widget:valign] properties.

Parameters:

  • widget (Gtk::Widget)

    a GtkWidget to be added to the container

Returns:

  • (nil)

#childGtk::Widget

The main child widget.

Returns:

#child=(child) ⇒ Gtk::Widget

The main child widget.

Parameters:

Returns:

#get_clip_overlay(widget) ⇒ Boolean

Gets whether widget should be clipped within the parent.

Parameters:

  • widget (Gtk::Widget)

    an overlay child of GtkOverlay

Returns:

  • (Boolean)

    whether the widget is clipped within the parent.

#get_measure_overlay(widget) ⇒ Boolean

Gets whether widget's size is included in the measurement of overlay.

Parameters:

  • widget (Gtk::Widget)

    an overlay child of GtkOverlay

Returns:

  • (Boolean)

    whether the widget is measured

#remove_overlay(widget) ⇒ nil

Removes an overlay that was added with gtk_overlay_add_overlay().

Parameters:

Returns:

  • (nil)

#set_clip_overlay(widget, clip_overlay) ⇒ nil

Sets whether widget should be clipped within the parent.

Parameters:

  • widget (Gtk::Widget)

    an overlay child of GtkOverlay

  • clip_overlay (Boolean)

    whether the child should be clipped

Returns:

  • (nil)

#set_measure_overlay(widget, measure) ⇒ nil

Sets whether widget is included in the measured size of overlay.

The overlay will request the size of the largest child that has this property set to true. Children who are not included may be drawn outside of overlay's allocation if they are too large.

Parameters:

  • widget (Gtk::Widget)

    an overlay child of GtkOverlay

  • measure (Boolean)

    whether the child should be measured

Returns:

  • (nil)