class Gtk::LayoutManager
- Gtk::LayoutManager
- GObject::Object
- Reference
- Object
Overview
Layout managers are delegate classes that handle the preferred size and the allocation of a widget.
You typically subclass GtkLayoutManager
if you want to implement a
layout policy for the children of a widget, or if you want to determine
the size of a widget depending on its contents.
Each GtkWidget
can only have a GtkLayoutManager
instance associated
to it at any given time; it is possible, though, to replace the layout
manager instance using Gtk::Widget#layout_manager=
.
Layout properties
A layout manager can expose properties for controlling the layout of
each child, by creating an object type derived from Gtk#LayoutChild
and installing the properties on it as normal GObject
properties.
Each GtkLayoutChild
instance storing the layout properties for a
specific child is created through the Gtk::LayoutManager#layout_child
method; a GtkLayoutManager
controls the creation of its GtkLayoutChild
instances by overriding the GtkLayoutManagerClass.create_layout_child()
virtual function. The typical implementation should look like:
WARNING ⚠️ The following code is in c ⚠️
static GtkLayoutChild *
create_layout_child (GtkLayoutManager *manager,
GtkWidget *container,
GtkWidget *child)
{
return g_object_new (your_layout_child_get_type (),
"layout-manager", manager,
"child-widget", child,
NULL);
}
The [property@Gtk.LayoutChild:layout-manager] and
[property@Gtk.LayoutChild:child-widget] properties
on the newly created GtkLayoutChild
instance are mandatory. The
GtkLayoutManager
will cache the newly created GtkLayoutChild
instance
until the widget is removed from its parent, or the parent removes the
layout manager.
Each GtkLayoutManager
instance creating a GtkLayoutChild
should use
Gtk::LayoutManager#layout_child
every time it needs to query
the layout properties; each GtkLayoutChild
instance should call
Gtk::LayoutManager#layout_changed
every time a property is
updated, in order to queue a new size measuring and allocation.
Direct Known Subclasses
- Adw::ClampLayout
- Gtk::BinLayout
- Gtk::BoxLayout
- Gtk::CenterLayout
- Gtk::ConstraintLayout
- Gtk::CustomLayout
- Gtk::FixedLayout
- Gtk::GridLayout
- Gtk::OverlayLayout
Defined in:
lib/gi-crystal/src/auto/gtk-4.0/layout_manager.crConstructors
-
.new
Initialize a new
LayoutManager
.
Class Method Summary
-
.g_type : UInt64
Returns the type id (GType) registered in GLib type system.
Instance Method Summary
-
#allocate(widget : Gtk::Widget, width : Int32, height : Int32, baseline : Int32) : Nil
Assigns the given @width, @height, and @baseline to a @widget, and computes the position and sizes of the children of the @widget using the layout management policy of @manager.
-
#layout_changed : Nil
Queues a resize on the
GtkWidget
using @manager, if any. -
#layout_child(child : Gtk::Widget) : Gtk::LayoutChild
Retrieves a
GtkLayoutChild
instance for theGtkLayoutManager
, creating one if necessary. -
#measure(widget : Gtk::Widget, orientation : Gtk::Orientation, for_size : Int32) : Nil
Measures the size of the @widget using @manager, for the given @orientation and size.
-
#request_mode : Gtk::SizeRequestMode
Retrieves the request mode of @manager.
-
#widget : Gtk::Widget?
Retrieves the
GtkWidget
using the givenGtkLayoutManager
.
Instance methods inherited from class GObject::Object
bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding
bind_property,
bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding
bind_property_full,
data(key : String) : Pointer(Void)?
data,
finalize
finalize,
freeze_notify : Nil
freeze_notify,
getv(names : Enumerable(String), values : Enumerable(_)) : Nil
getv,
notify(property_name : String) : Nil
notify,
notify_by_pspec(pspec : GObject::ParamSpec) : Nil
notify_by_pspec,
notify_signal
notify_signal,
property(property_name : String, value : _) : Nil
property,
qdata(quark : UInt32) : Pointer(Void)?
qdata,
ref_count : UInt32
ref_count,
run_dispose : Nil
run_dispose,
set_data(key : String, data : Pointer(Void)?) : Nil
set_data,
set_property(property_name : String, value : _) : Nil
set_property,
steal_data(key : String) : Pointer(Void)?
steal_data,
steal_qdata(quark : UInt32) : Pointer(Void)?
steal_qdata,
thaw_notify : Nil
thaw_notify,
to_unsafe : Pointer(Void)
to_unsafe,
watch_closure(closure : GObject::Closure) : Nil
watch_closure
Constructor methods inherited from class GObject::Object
cast(obj : GObject::Object) : self
cast,
cast?(obj : GObject::Object) : self?
cast?,
new(pointer, transfer : GICrystal::Transfer)new new, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv
Class methods inherited from class GObject::Object
compat_control(what : UInt64, data : Pointer(Void)?) : UInt64
compat_control,
g_type : UInt64
g_type,
interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec
interface_find_property,
interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec)
interface_list_properties
Constructor Detail
Class Method Detail
Instance Method Detail
Assigns the given @width, @height, and @baseline to a @widget, and computes the position and sizes of the children of the @widget using the layout management policy of @manager.
Queues a resize on the GtkWidget
using @manager, if any.
This function should be called by subclasses of GtkLayoutManager
in response to changes to their layout management policies.
Retrieves a GtkLayoutChild
instance for the GtkLayoutManager
,
creating one if necessary.
The @child widget must be a child of the widget using @manager.
The GtkLayoutChild
instance is owned by the GtkLayoutManager
,
and is guaranteed to exist as long as @child is a child of the
GtkWidget
using the given GtkLayoutManager
.
Measures the size of the @widget using @manager, for the given @orientation and size.
See the Gtk#Widget
documentation on layout management for
more details.