Creates a custom titlebar for a window.
<picture> <source srcset="headerbar-dark.png" media="(prefers-color-scheme: dark)"> <img alt="An example GtkHeaderBar" src="headerbar.png"> </picture> GtkHeaderBar is similar to a horizontal GtkCenterBox. It allows children to be placed at the start or the end. In addition, it allows the window title to be displayed. The title will be centered with respect to the width of the box, even if the children at either side take up different amounts of space.
GtkHeaderBar can add typical window frame controls, such as minimize, maximize and close buttons, or the window icon.
For these reasons, GtkHeaderBar is the natural choice for use as the custom titlebar widget of a GtkWindow (see [methodGtk.Window.set_titlebar]), as it gives features typical of titlebars while allowing the addition of child widgets.
## GtkHeaderBar as GtkBuildable
The GtkHeaderBar implementation of the GtkBuildable interface supports adding children at the start or end sides by specifying "start" or "end" as the "type" attribute of a <child> element, or setting the title widget by specifying "title" value.
By default the GtkHeaderBar uses a GtkLabel displaying the title of the window it is contained in as the title widget, equivalent to the following UI definition:
<object class="GtkLabel"> <property name="label"
translatable="yes">Label</property> <property
name="single-line-mode">True</property> <property
name="ellipsize">end</property> <property name="width-chars">5</property>
<style> <class name="title"/> </style> </object> </property> </object> ```
# CSS nodes
``` headerbar â°ââ windowhandle â°ââ box âââ box.start â âââ
windowcontrols.start â â°ââ [other children] âââ [Title Widget] â°ââ box.end
âââ [other children] â°ââ windowcontrols.end ```
A `GtkHeaderBar`'s CSS node is called `headerbar`. It contains a
`windowhandle` subnode, which contains a `box` subnode, which contains two
`box` subnodes at the start and end of the header bar, as well as a center
node that represents the title.
Each of the boxes contains a `windowcontrols` subnode, see
[classGtk.WindowControls] for details, as well as other children.
# Accessibility
`GtkHeaderBar` uses the [enumGtk.AccessibleRole.group] role.
<group>Layout containers</group>
<gtkada_demo>create_header_bar.adb</gtkada_demo>
function "+"
(Widget : access Gtk_Header_Bar_Record'Class)
return Gtk.Accessible.Gtk_Accessible
function "+"
(Widget : access Gtk_Header_Bar_Record'Class)
return Gtk.Buildable.Gtk_Buildable
function "+"
(Widget : access Gtk_Header_Bar_Record'Class)
return Gtk.Constraint_Target.Gtk_Constraint_Target
function "-"
(Interf : Gtk.Accessible.Gtk_Accessible)
return Gtk_Header_Bar
function "-"
(Interf : Gtk.Buildable.Gtk_Buildable)
return Gtk_Header_Bar
function "-"
(Interf : Gtk.Constraint_Target.Gtk_Constraint_Target)
return Gtk_Header_Bar
procedure Announce
(Self : not null access Gtk_Header_Bar_Record;
Message : UTF8_String;
Priority : Gtk.Accessible.Gtk_Accessible_Announcement_Priority)
Decoration_Layout_Property : constant Glib.Properties.Property_String;
The decoration layout for buttons.
If this property is not set, the [propertyGtk.Settings:gtk-decoration-layout] setting is used.
function Get_Accessible_Id
(Self : not null access Gtk_Header_Bar_Record) return UTF8_String
function Get_Accessible_Parent
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Accessible.Gtk_Accessible
function Get_Accessible_Role
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Accessible.Gtk_Accessible_Role
function Get_At_Context
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Atcontext.Gtk_Atcontext
function Get_Bounds
(Self : not null access Gtk_Header_Bar_Record;
X : out Glib.Gint;
Y : out Glib.Gint;
Width : out Glib.Gint;
Height : out Glib.Gint) return Boolean
function Get_Decoration_Layout
(Self : not null access Gtk_Header_Bar_Record) return UTF8_String
Gets the decoration layout of the header bar.
the decoration layout
function Get_First_Accessible_Child
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Accessible.Gtk_Accessible
function Get_Next_Accessible_Sibling
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Accessible.Gtk_Accessible
function Get_Platform_State
(Self : not null access Gtk_Header_Bar_Record;
State : Gtk.Accessible.Gtk_Accessible_Platform_State) return Boolean
function Get_Show_Title_Buttons
(Self : not null access Gtk_Header_Bar_Record) return Boolean
Returns whether this header bar shows the standard window title buttons.
true if title buttons are shown
function Get_Title_Widget
(Self : not null access Gtk_Header_Bar_Record)
return Gtk.Widget.Gtk_Widget
Retrieves the title widget of the header bar. See [methodGtk.HeaderBar.set_title_widget].
the title widget. Has transfer-ownership='none'.
function Get_Type return Glib.GType
function Get_Use_Native_Controls
(Self : not null access Gtk_Header_Bar_Record) return Boolean
Returns whether this header bar shows platform native window controls. Since: gtk+ 4.18
true if native window controls are shown
type Gtk_Header_Bar is access all Gtk_Header_Bar_Record'Class;
function Gtk_Header_Bar_New return Gtk_Header_Bar
Creates a new GtkHeaderBar widget.
type Gtk_Header_Bar_Record is new Gtk_Widget_Record with null record;
procedure Gtk_New (Self : out Gtk_Header_Bar)
Creates a new GtkHeaderBar widget. Initialize does nothing if the object was already created with another call to Initialize* or G_New.
package Implements_Gtk_Accessible is new Glib.Types.Implements
(Gtk.Accessible.Gtk_Accessible, Gtk_Header_Bar_Record, Gtk_Header_Bar);
package Implements_Gtk_Buildable is new Glib.Types.Implements
(Gtk.Buildable.Gtk_Buildable, Gtk_Header_Bar_Record, Gtk_Header_Bar);
package Implements_Gtk_Constraint_Target is new Glib.Types.Implements
(Gtk.Constraint_Target.Gtk_Constraint_Target, Gtk_Header_Bar_Record, Gtk_Header_Bar);
procedure Initialize (Self : not null access Gtk_Header_Bar_Record'Class)
Creates a new GtkHeaderBar widget. Initialize does nothing if the object was already created with another call to Initialize* or G_New.
procedure Pack_End
(Self : not null access Gtk_Header_Bar_Record;
Child : not null access Gtk.Widget.Gtk_Widget_Record'Class)
Adds a child to the header bar, packed with reference to the end.
the widget to be added to Bar
procedure Pack_Start
(Self : not null access Gtk_Header_Bar_Record;
Child : not null access Gtk.Widget.Gtk_Widget_Record'Class)
Adds a child to the header bar, packed with reference to the start.
the widget to be added to Bar
procedure Remove
(Self : not null access Gtk_Header_Bar_Record;
Child : not null access Gtk.Widget.Gtk_Widget_Record'Class)
Removes a child from the header bar. The child must have been added with [methodGtk.HeaderBar.pack_start], [methodGtk.HeaderBar.pack_end] or [methodGtk.HeaderBar.set_title_widget].
the child to remove
procedure Reset_Property
(Self : not null access Gtk_Header_Bar_Record;
Property : Gtk.Accessible.Gtk_Accessible_Property)
procedure Reset_Relation
(Self : not null access Gtk_Header_Bar_Record;
Relation : Gtk.Accessible.Gtk_Accessible_Relation)
procedure Reset_State
(Self : not null access Gtk_Header_Bar_Record;
State : Gtk.Accessible.Gtk_Accessible_State)
procedure Set_Accessible_Parent
(Self : not null access Gtk_Header_Bar_Record;
Parent : Gtk.Accessible.Gtk_Accessible;
Next_Sibling : Gtk.Accessible.Gtk_Accessible)
procedure Set_Decoration_Layout
(Self : not null access Gtk_Header_Bar_Record;
Layout : UTF8_String := "")
Sets the decoration layout for this header bar. This property overrides the [propertyGtk.Settings:gtk-decoration-layout] setting. There can be valid reasons for overriding the setting, such as a header bar design that does not allow for buttons to take room on the right, or only offers room for a single close button. Split header bars are another example for overriding the setting. The format of the string is button names, separated by commas. A colon separates the buttons that should appear on the left from those on the right. Recognized button names are minimize, maximize, close and icon (the window icon). For example, "icon:minimize,maximize,close" specifies an icon on the left, and minimize, maximize and close buttons on the right.
a decoration layout
procedure Set_Show_Title_Buttons
(Self : not null access Gtk_Header_Bar_Record;
Setting : Boolean)
Sets whether this header bar shows the standard window title buttons.
true to show standard title buttons
procedure Set_Title_Widget
(Self : not null access Gtk_Header_Bar_Record;
Title_Widget : access Gtk.Widget.Gtk_Widget_Record'Class)
Sets the title for the header bar. When set to NULL, the headerbar will display the title of the window it is contained in. The title should help a user identify the current view. To achieve the same style as the builtin title, use the "title" style class. You should set the title widget to NULL, for the window title label to be visible again.
a widget to use for a title
procedure Set_Use_Native_Controls
(Self : not null access Gtk_Header_Bar_Record;
Setting : Boolean)
Sets whether this header bar shows native window controls. This option shows the "stoplight" buttons on macOS. For Linux, this option has no effect. See also Using GTK on Apple macOS. Since: gtk+ 4.18
true to show native window controls
Show_Title_Buttons_Property : constant Glib.Properties.Property_Boolean;
Whether to show title buttons like close, minimize, maximize.
Which buttons are actually shown and where is determined by the [propertyGtk.HeaderBar:decoration-layout] property, and by the state of the window (e.g. a close button will not be shown if the window can't be closed).
Title_Widget_Property : constant Glib.Properties.Property_Object;
Type: Gtk.Widget.Gtk_Widget The title widget to display.
procedure Update_Next_Accessible_Sibling
(Self : not null access Gtk_Header_Bar_Record;
New_Sibling : Gtk.Accessible.Gtk_Accessible)
procedure Update_Platform_State
(Self : not null access Gtk_Header_Bar_Record;
State : Gtk.Accessible.Gtk_Accessible_Platform_State)
Use_Native_Controls_Property : constant Glib.Properties.Property_Boolean;
Whether to show platform native close/minimize/maximize buttons.
For macOS, the [propertyGtk.HeaderBar:decoration-layout] property can be used to enable/disable controls.
On Linux, this option has no effect.
See also Using GTK on Apple macOS.