OverlayProtocol

public protocol OverlayProtocol : BinProtocol

GtkOverlay is a container which contains a single main child, on top of which it can place “overlay” widgets. The position of each overlay widget is determined by its GtkWidget:halign and GtkWidget: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 GtkOverlay::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.

The OverlayProtocol protocol exposes the methods and properties of an underlying GtkOverlay instance. The default implementation of these can be found in the protocol extension below. For a concrete class that implements these methods and properties, see Overlay. Alternatively, use OverlayRef as a lighweight, unowned reference if you already have an instance you just want to use.

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  • ptr

    Untyped pointer to the underlying GtkOverlay instance.

    Declaration

    Swift

    var ptr: UnsafeMutableRawPointer! { get }
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  • overlay_ptr Default implementation

    Typed pointer to the underlying GtkOverlay instance.

    Default Implementation

    Return the stored, untyped pointer as a typed pointer to the GtkOverlay instance.

    Declaration

    Swift

    var overlay_ptr: UnsafeMutablePointer<GtkOverlay>! { get }
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  • Required Initialiser for types conforming to OverlayProtocol

    Declaration

    Swift

    init(raw: UnsafeMutableRawPointer)
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Overlay Class

  • Bind a OverlayPropertyName source property to a given target object.

    Declaration

    Swift

    @discardableResult
@inlinable
func bind<Q, T>(property source_property: OverlayPropertyName, to target: T, _ target_property: Q, flags f: BindingFlags = .default, transformFrom transform_from: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }, transformTo transform_to: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }) -> BindingRef! where Q : PropertyNameProtocol, T : ObjectProtocol

    Parameters

    source_property

    the source property to bind
    target

    the target object to bind to
    target_property

    the target property to bind to
    flags

    the flags to pass to the Binding
    transform_from

    ValueTransformer to use for forward transformation
    transform_to

    ValueTransformer to use for backwards transformation

    Return Value

    binding reference or nil in case of an error

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  • get(property:) Extension method

    Get the value of a Overlay property

    Declaration

    Swift

    @inlinable
func get(property: OverlayPropertyName) -> GLibObject.Value

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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  • set(property:value:) Extension method

    Set the value of a Overlay property. Note that this will only have an effect on properties that are writable and not construct-only!

    Declaration

    Swift

    @inlinable
func set(property: OverlayPropertyName, value v: GLibObject.Value)

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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Overlay signals

  • Connect a Swift signal handler to the given, typed OverlaySignalName signal

    Declaration

    Swift

    @discardableResult
@inlinable
func connect(signal s: OverlaySignalName, flags f: ConnectFlags = ConnectFlags(0), handler h: @escaping SignalHandler) -> Int

    Parameters

    signal

    The signal to connect
    flags

    The connection flags to use
    data

    A pointer to user data to provide to the callback
    destroyData

    A GClosureNotify C function to destroy the data pointed to by userData
    handler

    The Swift signal handler (function or callback) to invoke on the given signal

    Return Value

    The signal handler ID (always greater than 0 for successful connections)

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  • Connect a C signal handler to the given, typed OverlaySignalName signal

    Declaration

    Swift

    @discardableResult
@inlinable
func connect(signal s: OverlaySignalName, flags f: ConnectFlags = ConnectFlags(0), data userData: gpointer!, destroyData destructor: GClosureNotify? = nil, signalHandler h: @escaping GCallback) -> Int

    Parameters

    signal

    The signal to connect
    flags

    The connection flags to use
    data

    A pointer to user data to provide to the callback
    destroyData

    A GClosureNotify C function to destroy the data pointed to by userData
    signalHandler

    The C function to be called on the given signal

    Return Value

    The signal handler ID (always greater than 0 for successful connections)

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  • getChildPositionSignal Extension method

    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.

    Note

    This represents the underlying get-child-position signal

    Warning

    a onGetChildPosition wrapper for this signal could not be generated because it contains unimplemented features: { (2) out or inout argument direction is not allowed }

    Note

    Instead, you can connect getChildPositionSignal using the connect(signal:) methods

    Declaration

    Swift

    static var getChildPositionSignal: OverlaySignalName { get }

    Parameters

    flags

    Flags
    unownedSelf

    Reference to instance of self
    widget

    the child widget to position
    allocation

    return location for the allocation
    handler

    true if the allocation has been filled
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Overlay Class: OverlayProtocol extension (methods and fields)

  • addOverlay(widget:) Extension method

    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 GtkWidget:halign and GtkWidget:valign properties.

    Declaration

    Swift

    @inlinable
func addOverlay<WidgetT>(widget: WidgetT) where WidgetT : WidgetProtocol
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  • Convenience function to get the value of the GtkOverlay:pass-through child property for widget.

    Declaration

    Swift

    @inlinable
func getOverlayPassThrough<WidgetT>(widget: WidgetT) -> Bool where WidgetT : WidgetProtocol
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  • reorderOverlay(child:index:) Extension method

    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 GtkOverlay: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.

    Declaration

    Swift

    @inlinable
func reorderOverlay<WidgetT>(child: WidgetT, index: Int) where WidgetT : WidgetProtocol
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  • Convenience function to set the value of the GtkOverlay:pass-through child property for widget.

    Declaration

    Swift

    @inlinable
func setOverlayPassThrough<WidgetT>(widget: WidgetT, passThrough: Bool) where WidgetT : WidgetProtocol
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  • parent Extension method

    Undocumented

    Declaration

    Swift

    @inlinable
var parent: GtkBin { get }
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