Struct gtk4::Overlay

source ·
#[repr(transparent)]
pub struct Overlay { /* private fields */ }
Expand description

Overlay 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 property::Widget::halign and property::Widget::valign properties. E.g. a widget with both alignments set to Align::Start will be placed at the top left corner of the Overlay container, whereas an overlay with halign set to Align::Center and valign set to Align::End will be placed a the bottom edge of the Overlay, 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 signal::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 Overlay implementation of the Buildable interface supports placing a child as an overlay by specifying “overlay” as the “type” attribute of a <child> element.

CSS nodes

Overlay 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.

Implements

WidgetExt, glib::ObjectExt, AccessibleExt, BuildableExt, ConstraintTargetExt, WidgetExtManual, AccessibleExtManual

Implementations§

Creates a new Overlay.

Returns

a new Overlay object.

Creates a new builder-pattern struct instance to construct Overlay objects.

This method returns an instance of OverlayBuilder which can be used to create Overlay objects.

Adds @widget to @self.

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

The position at which @widget is placed is determined from its property::Widget::halign and property::Widget::valign properties.

widget

a Widget to be added to the container

Gets the child widget of @self.

Returns

the child widget of @self

Gets whether @widget should be clipped within the parent.

widget

an overlay child of Overlay

Returns

whether the widget is clipped within the parent.

Gets whether @widget’s size is included in the measurement of @self.

widget

an overlay child of Overlay

Returns

whether the widget is measured

Removes an overlay that was added with gtk_overlay_add_overlay().

widget

a Widget to be removed

Sets the child widget of @self.

child

the child widget

Sets whether @widget should be clipped within the parent.

widget

an overlay child of Overlay

clip_overlay

whether the child should be clipped

Sets whether @widget is included in the measured size of @self.

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 @self’s allocation if they are too large.

widget

an overlay child of Overlay

measure

whether the child should be measured

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 Align::Fill will cause the overlay to be full-width/height). If the main child is a ScrolledWindow, the overlays are placed relative to its contents.

widget

the child widget to position

Returns

true if the @allocation has been filled

allocation

return location for the allocation

Trait Implementations§

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This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
Returns the type identifier of Self.

Auto Trait Implementations§

Blanket Implementations§

Updates an array of accessible properties. Read more
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