OverlayProtocol

public protocol OverlayProtocol : WidgetProtocol

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.

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

    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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  • The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

    Note that getting this signal doesn’t itself guarantee that the value of the property has actually changed. When it is emitted is determined by the derived GObject class. If the implementor did not create the property with G_PARAM_EXPLICIT_NOTIFY, then any call to g_object_set_property() results in notify being emitted, even if the new value is the same as the old. If they did pass G_PARAM_EXPLICIT_NOTIFY, then this signal is emitted only when they explicitly call g_object_notify() or g_object_notify_by_pspec(), and common practice is to do that only when the value has actually changed.

    This signal is typically used to obtain change notification for a single property, by specifying the property name as a detail in the g_signal_connect() call, like this:

    (C Language Example):

    g_signal_connect (text_view->buffer, "notify::paste-target-list",
                  G_CALLBACK (gtk_text_view_target_list_notify),
                  text_view)

    It is important to note that you must use canonical parameter names as detail strings for the notify signal.

    Note

    This represents the underlying notify::child signal

    Declaration

    Swift

    @discardableResult
@inlinable
func onNotifyChild(flags: ConnectFlags = ConnectFlags(0), handler: @escaping (_ unownedSelf: OverlayRef, _ pspec: ParamSpecRef) -> Void) -> Int

    Parameters

    flags

    Flags
    unownedSelf

    Reference to instance of self
    pspec

    the GParamSpec of the property which changed.
    handler

    The signal handler to call Run the given callback whenever the notifyChild signal is emitted
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  • notifyChildSignal Extension method

    Typed notify::child signal for using the connect(signal:) methods

    Declaration

    Swift

    static var notifyChildSignal: OverlaySignalName { get }
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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 [methodGtk.Overlay.set_child].

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

    Declaration

    Swift

    @inlinable
func addOverlay<WidgetT>(widget: WidgetT) where WidgetT : WidgetProtocol
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  • getChild() Extension method

    Gets the child widget of overlay.

    Declaration

    Swift

    @inlinable
func getChild() -> WidgetRef!
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  • getClipOverlay(widget:) Extension method

    Gets whether widget should be clipped within the parent.

    Declaration

    Swift

    @inlinable
func getClipOverlay<WidgetT>(widget: WidgetT) -> Bool where WidgetT : WidgetProtocol
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  • getMeasureOverlay(widget:) Extension method

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

    Declaration

    Swift

    @inlinable
func getMeasureOverlay<WidgetT>(widget: WidgetT) -> Bool where WidgetT : WidgetProtocol
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  • removeOverlay(widget:) Extension method

    Removes an overlay that was added with gtk_overlay_add_overlay().

    Declaration

    Swift

    @inlinable
func removeOverlay<WidgetT>(widget: WidgetT) where WidgetT : WidgetProtocol
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  • set(child:) Extension method

    Sets the child widget of overlay.

    Declaration

    Swift

    @inlinable
func set(child: WidgetRef? = nil)
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  • set(child:) Extension method

    Sets the child widget of overlay.

    Declaration

    Swift

    @inlinable
func set<WidgetT>(child: WidgetT?) where WidgetT : WidgetProtocol
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  • Sets whether widget should be clipped within the parent.

    Declaration

    Swift

    @inlinable
func setClipOverlay<WidgetT>(widget: WidgetT, clipOverlay: Bool) where WidgetT : WidgetProtocol
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  • 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.

    Declaration

    Swift

    @inlinable
func setMeasureOverlay<WidgetT>(widget: WidgetT, measure: Bool) where WidgetT : WidgetProtocol
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  • child Extension method

    Undocumented

    Declaration

    Swift

    @inlinable
var child: WidgetRef! { get nonmutating set }
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