Struct gtk4::Overlay[][src]

pub struct Overlay(_);
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 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

Returns a copy of the value. Read more

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Formats the value using the given formatter. Read more

Returns the “default value” for a type. Read more

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Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

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.

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Tries to downcast to a subclass or interface implementor T. Read more

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Tries to cast to an object of type T. This handles upcasting, downcasting and casting between interface and interface implementors. All checks are performed at runtime, while downcast and upcast will do many checks at compile-time already. Read more

Tries to cast to reference to an object of type T. This handles upcasting, downcasting and casting between interface and interface implementors. All checks are performed at runtime, while downcast and upcast will do many checks at compile-time already. Read more

Casts to T unconditionally. Read more

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Performs the conversion.

Performs the conversion.

Returns true if the object is an instance of (can be cast to) T.

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Same as connect but takes a SignalId instead of a signal name.

Same as connect_local but takes a SignalId instead of a signal name.

Same as connect_unsafe but takes a SignalId instead of a signal name.

Emit signal by signal id.

Same as emit but takes Value for the arguments.

Emit signal by its name.

Same as emit_by_name but takes Value for the arguments.

Emit signal with details by signal id.

Same as emit_with_details but takes Value for the arguments.

The resulting type after obtaining ownership.

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The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.