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Stores geometrical information for a series of rows in a GtkCellArea

The GtkCellAreaContext object is created by a given GtkCellArea implementation via its GtkCellAreaClass.create_context() virtual method and is used to store cell sizes and alignments for a series of GtkTreeModel rows that are requested and rendered in the same context.

GtkCellLayout widgets can create any number of contexts in which to request and render groups of data rows. However, it’s important that the same context which was used to request sizes for a given GtkTreeModel row also be used for the same row when calling other GtkCellArea APIs such as gtk_cell_area_render() and gtk_cell_area_event().

Hierarchy

Index

Constructors

Properties

The GtkCellArea this context was created by

g_type_instance: TypeInstance
minimum_height: number

The minimum height for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using gtk_cell_area_get_preferred_height().

minimum_width: number

The minimum width for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using gtk_cell_area_get_preferred_width().

natural_height: number

The natural height for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using gtk_cell_area_get_preferred_height().

natural_width: number

The natural width for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using gtk_cell_area_get_preferred_width().

name: string

Methods

  • allocate(width: number, height: number): void
  • Allocates a width and/or a height for all rows which are to be rendered with context.

    Usually allocation is performed only horizontally or sometimes vertically since a group of rows are usually rendered side by side vertically or horizontally and share either the same width or the same height. Sometimes they are allocated in both horizontal and vertical orientations producing a homogeneous effect of the rows. This is generally the case for GtkTreeView when GtkTreeView:fixed-height-mode is enabled.

    Parameters

    • width: number

      the allocated width for all GtkTreeModel rows rendered with context, or -1

    • height: number

      the allocated height for all GtkTreeModel rows rendered with context, or -1

    Returns void

  • Creates a binding between source_property on source and target_property on target.

    Whenever the source_property is changed the target_property is updated using the same value. For instance:

      g_object_bind_property (action, "active", widget, "sensitive", 0);
    

    Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.

    If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual: if target_property on target changes then the source_property on source will be updated as well.

    The binding will automatically be removed when either the source or the target instances are finalized. To remove the binding without affecting the source and the target you can just call g_object_unref() on the returned #GBinding instance.

    Removing the binding by calling g_object_unref() on it must only be done if the binding, source and target are only used from a single thread and it is clear that both source and target outlive the binding. Especially it is not safe to rely on this if the binding, source or target can be finalized from different threads. Keep another reference to the binding and use g_binding_unbind() instead to be on the safe side.

    A #GObject can have multiple bindings.

    Parameters

    • source_property: string

      the property on source to bind

    • target: GObject.Object

      the target #GObject

    • target_property: string

      the property on target to bind

    • flags: BindingFlags

      flags to pass to #GBinding

    Returns Binding

  • Creates a binding between source_property on source and target_property on target, allowing you to set the transformation functions to be used by the binding.

    This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.

    Parameters

    • source_property: string

      the property on source to bind

    • target: GObject.Object

      the target #GObject

    • target_property: string

      the property on target to bind

    • flags: BindingFlags

      flags to pass to #GBinding

    • transform_to: TClosure<any, any>

      a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default

    • transform_from: TClosure<any, any>

      a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default

    Returns Binding

  • connect_after(sigName: "notify::area", callback: (($obj: Gtk.CellAreaContext, pspec: ParamSpec) => void)): number
  • connect_after(sigName: "notify::minimum-height", callback: (($obj: Gtk.CellAreaContext, pspec: ParamSpec) => void)): number
  • connect_after(sigName: "notify::minimum-width", callback: (($obj: Gtk.CellAreaContext, pspec: ParamSpec) => void)): number
  • connect_after(sigName: "notify::natural-height", callback: (($obj: Gtk.CellAreaContext, pspec: ParamSpec) => void)): number
  • connect_after(sigName: "notify::natural-width", callback: (($obj: Gtk.CellAreaContext, pspec: ParamSpec) => void)): number
  • connect_after(sigName: string, callback: ((...args: any[]) => void)): number
  • disconnect(id: number): void
  • emit(sigName: "notify::area", ...args: any[]): void
  • emit(sigName: "notify::minimum-height", ...args: any[]): void
  • emit(sigName: "notify::minimum-width", ...args: any[]): void
  • emit(sigName: "notify::natural-height", ...args: any[]): void
  • emit(sigName: "notify::natural-width", ...args: any[]): void
  • emit(sigName: string, ...args: any[]): void
  • force_floating(): void
  • This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().

    Returns void

  • freeze_notify(): void
  • Increases the freeze count on object. If the freeze count is non-zero, the emission of "notify" signals on object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen.

    This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.

    Returns void

  • get_allocation(): [number, number]
  • Fetches the current allocation size for context.

    If the context was not allocated in width or height, or if the context was recently reset with gtk_cell_area_context_reset(), the returned value will be -1.

    Returns [number, number]

  • Fetches the GtkCellArea this context was created by.

    This is generally unneeded by layouting widgets; however, it is important for the context implementation itself to fetch information about the area it is being used for.

    For instance at GtkCellAreaContextClass.allocate() time it’s important to know details about any cell spacing that the GtkCellArea is configured with in order to compute a proper allocation.

    Returns Gtk.CellArea

  • get_data(key?: string): object
  • Gets a named field from the objects table of associations (see g_object_set_data()).

    Parameters

    • Optional key: string

      name of the key for that association

    Returns object

  • get_preferred_height(): [number, number]
  • Gets the accumulative preferred height for all rows which have been requested with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are 0.

    Returns [number, number]

  • get_preferred_height_for_width(width: number): [number, number]
  • Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

    Parameters

    • width: number

      a proposed width for allocation

    Returns [number, number]

  • get_preferred_width(): [number, number]
  • Gets the accumulative preferred width for all rows which have been requested with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are 0.

    Returns [number, number]

  • get_preferred_width_for_height(height: number): [number, number]
  • Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

    Parameters

    • height: number

      a proposed height for allocation

    Returns [number, number]

  • get_property(property_name?: string, value?: any): void
  • Gets a property of an object.

    The value can be:

    • an empty #GValue initialized by %G_VALUE_INIT, which will be automatically initialized with the expected type of the property (since GLib 2.60)
    • a #GValue initialized with the expected type of the property
    • a #GValue initialized with a type to which the expected type of the property can be transformed

    In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().

    Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.

    Parameters

    • Optional property_name: string

      the name of the property to get

    • Optional value: any

      return location for the property value

    Returns void

  • get_qdata(quark: number): object
  • getv(names: string[], values: any[]): void
  • Gets n_properties properties for an object. Obtained properties will be set to values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.

    Parameters

    • names: string[]

      the names of each property to get

    • values: any[]

      the values of each property to get

    Returns void

  • is_floating(): boolean
  • notify(property_name: string): void
  • Emits a "notify" signal for the property property_name on object.

    When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.

    Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

    Parameters

    • property_name: string

      the name of a property installed on the class of object.

    Returns void

  • Emits a "notify" signal for the property specified by pspec on object.

    This function omits the property name lookup, hence it is faster than g_object_notify().

    One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:

      enum
    {
    PROP_0,
    PROP_FOO,
    PROP_LAST
    };

    static GParamSpec *properties[PROP_LAST];

    static void
    my_object_class_init (MyObjectClass *klass)
    {
    properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
    0, 100,
    50,
    G_PARAM_READWRITE);
    g_object_class_install_property (gobject_class,
    PROP_FOO,
    properties[PROP_FOO]);
    }

    and then notify a change on the "foo" property with:

      g_object_notify_by_pspec (self, properties[PROP_FOO]);
    

    Parameters

    • pspec: ParamSpec

      the #GParamSpec of a property installed on the class of object.

    Returns void

  • push_preferred_height(minimum_height: number, natural_height: number): void
  • Causes the minimum and/or natural height to grow if the new proposed sizes exceed the current minimum and natural height.

    This is used by GtkCellAreaContext implementations during the request process over a series of GtkTreeModel rows to progressively push the requested height over a series of gtk_cell_area_get_preferred_height() requests.

    Parameters

    • minimum_height: number

      the proposed new minimum height for context

    • natural_height: number

      the proposed new natural height for context

    Returns void

  • push_preferred_width(minimum_width: number, natural_width: number): void
  • Causes the minimum and/or natural width to grow if the new proposed sizes exceed the current minimum and natural width.

    This is used by GtkCellAreaContext implementations during the request process over a series of GtkTreeModel rows to progressively push the requested width over a series of gtk_cell_area_get_preferred_width() requests.

    Parameters

    • minimum_width: number

      the proposed new minimum width for context

    • natural_width: number

      the proposed new natural width for context

    Returns void

  • Increases the reference count of object.

    Since GLib 2.56, if GLIB_VERSION_MAX_ALLOWED is 2.56 or greater, the type of object will be propagated to the return type (using the GCC typeof() extension), so any casting the caller needs to do on the return type must be explicit.

    Returns GObject.Object

  • Increase the reference count of object, and possibly remove the [floating][floating-ref] reference, if object has a floating reference.

    In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.

    Since GLib 2.56, the type of object will be propagated to the return type under the same conditions as for g_object_ref().

    Returns GObject.Object

  • reset(): void
  • Resets any previously cached request and allocation data.

    When underlying GtkTreeModel data changes its important to reset the context if the content size is allowed to shrink. If the content size is only allowed to grow (this is usually an option for views rendering large data stores as a measure of optimization), then only the row that changed or was inserted needs to be (re)requested with gtk_cell_area_get_preferred_width().

    When the new overall size of the context requires that the allocated size changes (or whenever this allocation changes at all), the variable row sizes need to be re-requested for every row.

    For instance, if the rows are displayed all with the same width from top to bottom then a change in the allocated width necessitates a recalculation of all the displayed row heights using gtk_cell_area_get_preferred_height_for_width().

    Returns void

  • run_dispose(): void
  • Releases all references to other objects. This can be used to break reference cycles.

    This function should only be called from object system implementations.

    Returns void

  • set_data(key: string, data?: object): void
  • Each object carries around a table of associations from strings to pointers. This function lets you set an association.

    If the object already had an association with that name, the old association will be destroyed.

    Internally, the key is converted to a #GQuark using g_quark_from_string(). This means a copy of key is kept permanently (even after object has been finalized) — so it is recommended to only use a small, bounded set of values for key in your program, to avoid the #GQuark storage growing unbounded.

    Parameters

    • key: string

      name of the key

    • Optional data: object

      data to associate with that key

    Returns void

  • set_property(property_name: string, value?: any): void
  • steal_data(key?: string): object
  • Remove a specified datum from the object's data associations, without invoking the association's destroy handler.

    Parameters

    • Optional key: string

      name of the key

    Returns object

  • steal_qdata(quark: number): object
  • This function gets back user data pointers stored via g_object_set_qdata() and removes the data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example:

    void
    object_add_to_user_list (GObject *object,
    const gchar *new_string)
    {
    // the quark, naming the object data
    GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
    // retrieve the old string list
    GList *list = g_object_steal_qdata (object, quark_string_list);

    // prepend new string
    list = g_list_prepend (list, g_strdup (new_string));
    // this changed 'list', so we need to set it again
    g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
    }
    static void
    free_string_list (gpointer data)
    {
    GList *node, *list = data;

    for (node = list; node; node = node->next)
    g_free (node->data);
    g_list_free (list);
    }

    Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().

    Parameters

    • quark: number

      A #GQuark, naming the user data pointer

    Returns object

  • thaw_notify(): void
  • Reverts the effect of a previous call to g_object_freeze_notify(). The freeze count is decreased on object and when it reaches zero, queued "notify" signals are emitted.

    Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.

    It is an error to call this function when the freeze count is zero.

    Returns void

  • unref(): void
  • Decreases the reference count of object. When its reference count drops to 0, the object is finalized (i.e. its memory is freed).

    If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.

    Returns void

  • vfunc_allocate(width: number, height: number): void
  • Allocates a width and/or a height for all rows which are to be rendered with context.

    Usually allocation is performed only horizontally or sometimes vertically since a group of rows are usually rendered side by side vertically or horizontally and share either the same width or the same height. Sometimes they are allocated in both horizontal and vertical orientations producing a homogeneous effect of the rows. This is generally the case for GtkTreeView when GtkTreeView:fixed-height-mode is enabled.

    virtual

    Parameters

    • width: number

      the allocated width for all GtkTreeModel rows rendered with context, or -1

    • height: number

      the allocated height for all GtkTreeModel rows rendered with context, or -1

    Returns void

  • vfunc_constructed(): void
  • vfunc_dispatch_properties_changed(n_pspecs: number, pspecs: ParamSpec): void
  • vfunc_dispose(): void
  • vfunc_finalize(): void
  • vfunc_get_preferred_height_for_width(width: number): [number, number]
  • Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

    virtual

    Parameters

    • width: number

      a proposed width for allocation

    Returns [number, number]

  • vfunc_get_preferred_width_for_height(height: number): [number, number]
  • Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

    After gtk_cell_area_context_reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

    virtual

    Parameters

    • height: number

      a proposed height for allocation

    Returns [number, number]

  • vfunc_get_property(property_id: number, value?: any, pspec?: ParamSpec): void
  • Emits a "notify" signal for the property property_name on object.

    When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.

    Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

    virtual

    Parameters

    Returns void

  • vfunc_reset(): void
  • Resets any previously cached request and allocation data.

    When underlying GtkTreeModel data changes its important to reset the context if the content size is allowed to shrink. If the content size is only allowed to grow (this is usually an option for views rendering large data stores as a measure of optimization), then only the row that changed or was inserted needs to be (re)requested with gtk_cell_area_get_preferred_width().

    When the new overall size of the context requires that the allocated size changes (or whenever this allocation changes at all), the variable row sizes need to be re-requested for every row.

    For instance, if the rows are displayed all with the same width from top to bottom then a change in the allocated width necessitates a recalculation of all the displayed row heights using gtk_cell_area_get_preferred_height_for_width().

    virtual

    Returns void

  • vfunc_set_property(property_id: number, value?: any, pspec?: ParamSpec): void
  • watch_closure(closure: TClosure<any, any>): void
  • This function essentially limits the life time of the closure to the life time of the object. That is, when the object is finalized, the closure is invalidated by calling g_closure_invalidate() on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, g_object_ref() and g_object_unref() are added as marshal guards to the closure, to ensure that an extra reference count is held on object during invocation of the closure. Usually, this function will be called on closures that use this object as closure data.

    Parameters

    • closure: TClosure<any, any>

      #GClosure to watch

    Returns void

  • compat_control(what: number, data: object): number
  • Find the #GParamSpec with the given name for an interface. Generally, the interface vtable passed in as g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().

    Parameters

    • g_iface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface

    • property_name: string

      name of a property to look up.

    Returns ParamSpec

  • Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.

    This function is meant to be called from the interface's default vtable initialization function (the class_init member of #GTypeInfo.) It must not be called after after class_init has been called for any object types implementing this interface.

    If pspec is a floating reference, it will be consumed.

    Parameters

    • g_iface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface.

    • pspec: ParamSpec

      the #GParamSpec for the new property

    Returns void

  • Lists the properties of an interface.Generally, the interface vtable passed in as g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().

    Parameters

    • g_iface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface

    Returns ParamSpec[]

  • Creates a new instance of a #GObject subtype and sets its properties.

    Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.

    Parameters

    • object_type: GType<unknown>

      the type id of the #GObject subtype to instantiate

    • parameters: GObject.Parameter[]

      an array of #GParameter

    Returns GObject.Object

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