### Class

# Gtk CellArea

deprecated: 4.10

#### Description [src]

    abstract class Gtk.CellArea : GObject.InitiallyUnowned
      implements Gtk.Buildable, Gtk.CellLayout {
      /* No available fields */
    }

An abstract class for laying out `GtkCellRenderer`s

The `GtkCellArea` is an abstract class for `GtkCellLayout` widgets (also referred to as “layouting widgets”) to interface with an arbitrary number of `GtkCellRenderer`s and interact with the user for a given `GtkTreeModel` row.

The cell area handles events, focus navigation, drawing and size requests and allocations for a given row of data.

Usually users dont have to interact with the `GtkCellArea` directly unless they are implementing a cell-layouting widget themselves.

## Requesting area sizes

As outlined in GtkWidget’s geometry management section, GTK uses a height-for-width geometry management system to compute the sizes of widgets and user interfaces. `GtkCellArea` uses the same semantics to calculate the size of an area for an arbitrary number of `GtkTreeModel` rows.

When requesting the size of a cell area one needs to calculate the size for a handful of rows, and this will be done differently by different layouting widgets. For instance a `GtkTreeViewColumn` always lines up the areas from top to bottom while a `GtkIconView` on the other hand might enforce that all areas received the same width and wrap the areas around, requesting height for more cell areas when allocated less width.

It’s also important for areas to maintain some cell alignments with areas rendered for adjacent rows (cells can appear “columnized” inside an area even when the size of cells are different in each row). For this reason the `GtkCellArea` uses a `GtkCellAreaContext` object to store the alignments and sizes along the way (as well as the overall largest minimum and natural size for all the rows which have been calculated with the said context).

The `GtkCellAreaContext` is an opaque object specific to the `GtkCellArea` which created it (see `gtk_cell_area_create_context()`).

The owning cell-layouting widget can create as many contexts as it wishes to calculate sizes of rows which should receive the same size in at least one orientation (horizontally or vertically), However, it’s important that the same `GtkCellAreaContext` which was used to request the sizes for a given `GtkTreeModel` row be used when rendering or processing events for that row.

In order to request the width of all the rows at the root level of a `GtkTreeModel` one would do the following:

    GtkTreeIter iter;
    int minimum_width;
    int natural_width;

    valid = gtk_tree_model_get_iter_first (model, &iter);
    while (valid)
      {
        gtk_cell_area_apply_attributes (area, model, &iter, FALSE, FALSE);
        gtk_cell_area_get_preferred_width (area, context, widget, NULL, NULL);

        valid = gtk_tree_model_iter_next (model, &iter);
      }

    gtk_cell_area_context_get_preferred_width (context, &minimum_width, &natural_width);

Note that in this example it’s not important to observe the returned minimum and natural width of the area for each row unless the cell-layouting object is actually interested in the widths of individual rows. The overall width is however stored in the accompanying `GtkCellAreaContext` object and can be consulted at any time.

This can be useful since `GtkCellLayout` widgets usually have to support requesting and rendering rows in treemodels with an exceedingly large amount of rows. The `GtkCellLayout` widget in that case would calculate the required width of the rows in an idle or timeout source (see `g_timeout_add()`) and when the widget is requested its actual width in `Gtk.WidgetClass.measure` it can simply consult the width accumulated so far in the `GtkCellAreaContext` object.

A simple example where rows are rendered from top to bottom and take up the full width of the layouting widget would look like:

    static void
    foo_get_preferred_width (GtkWidget *widget,
                             int       *minimum_size,
                             int       *natural_size)
    {
      Foo *self = FOO (widget);
      FooPrivate *priv = foo_get_instance_private (self);

      foo_ensure_at_least_one_handfull_of_rows_have_been_requested (self);

      gtk_cell_area_context_get_preferred_width (priv->context, minimum_size, natural_size);
    }

In the above example the `Foo` widget has to make sure that some row sizes have been calculated (the amount of rows that `Foo` judged was appropriate to request space for in a single timeout iteration) before simply returning the amount of space required by the area via the `GtkCellAreaContext`.

Requesting the height for width (or width for height) of an area is a similar task except in this case the `GtkCellAreaContext` does not store the data (actually, it does not know how much space the layouting widget plans to allocate it for every row. It’s up to the layouting widget to render each row of data with the appropriate height and width which was requested by the `GtkCellArea`).

In order to request the height for width of all the rows at the root level of a `GtkTreeModel` one would do the following:

    GtkTreeIter iter;
    int minimum_height;
    int natural_height;
    int full_minimum_height = 0;
    int full_natural_height = 0;

    valid = gtk_tree_model_get_iter_first (model, &iter);
    while (valid)
      {
        gtk_cell_area_apply_attributes (area, model, &iter, FALSE, FALSE);
        gtk_cell_area_get_preferred_height_for_width (area, context, widget,
                                                      width, &minimum_height, &natural_height);

        if (width_is_for_allocation)
           cache_row_height (&iter, minimum_height, natural_height);

        full_minimum_height += minimum_height;
        full_natural_height += natural_height;

        valid = gtk_tree_model_iter_next (model, &iter);
      }

Note that in the above example we would need to cache the heights returned for each row so that we would know what sizes to render the areas for each row. However we would only want to really cache the heights if the request is intended for the layouting widgets real allocation.

In some cases the layouting widget is requested the height for an arbitrary for_width, this is a special case for layouting widgets who need to request size for tens of thousands of rows. For this case it’s only important that the layouting widget calculate one reasonably sized chunk of rows and return that height synchronously. The reasoning here is that any layouting widget is at least capable of synchronously calculating enough height to fill the screen height (or scrolled window height) in response to a single call to `Gtk.WidgetClass.measure`. Returning a perfect height for width that is larger than the screen area is inconsequential since after the layouting receives an allocation from a scrolled window it simply continues to drive the scrollbar values while more and more height is required for the row heights that are calculated in the background.

## Rendering Areas

Once area sizes have been acquired at least for the rows in the visible area of the layouting widget they can be rendered at `Gtk.WidgetClass.snapshot` time.

A crude example of how to render all the rows at the root level runs as follows:

    GtkAllocation allocation;
    GdkRectangle cell_area = { 0, };
    GtkTreeIter iter;
    int minimum_width;
    int natural_width;

    gtk_widget_get_allocation (widget, &allocation);
    cell_area.width = allocation.width;

    valid = gtk_tree_model_get_iter_first (model, &iter);
    while (valid)
      {
        cell_area.height = get_cached_height_for_row (&iter);

        gtk_cell_area_apply_attributes (area, model, &iter, FALSE, FALSE);
        gtk_cell_area_render (area, context, widget, cr,
                              &cell_area, &cell_area, state_flags, FALSE);

        cell_area.y += cell_area.height;

        valid = gtk_tree_model_iter_next (model, &iter);
      }

Note that the cached height in this example really depends on how the layouting widget works. The layouting widget might decide to give every row its minimum or natural height or, if the model content is expected to fit inside the layouting widget without scrolling, it would make sense to calculate the allocation for each row at the time the widget is allocated using `gtk_distribute_natural_allocation()`.

## Handling Events and Driving Keyboard Focus

Passing events to the area is as simple as handling events on any normal widget and then passing them to the `gtk_cell_area_event()` API as they come in. Usually `GtkCellArea` is only interested in button events, however some customized derived areas can be implemented who are interested in handling other events. Handling an event can trigger the `GtkCellArea::focus-changed` signal to fire; as well as `GtkCellArea::add-editable` in the case that an editable cell was clicked and needs to start editing. You can call `gtk_cell_area_stop_editing()` at any time to cancel any cell editing that is currently in progress.

The `GtkCellArea` drives keyboard focus from cell to cell in a way similar to `GtkWidget`. For layouting widgets that support giving focus to cells it’s important to remember to pass `GTK_CELL_RENDERER_FOCUSED` to the area functions for the row that has focus and to tell the area to paint the focus at render time.

Layouting widgets that accept focus on cells should implement the `Gtk.WidgetClass.focus` virtual method. The layouting widget is always responsible for knowing where `GtkTreeModel` rows are rendered inside the widget, so at `Gtk.WidgetClass.focus` time the layouting widget should use the `GtkCellArea` methods to navigate focus inside the area and then observe the `GtkDirectionType` to pass the focus to adjacent rows and areas.

A basic example of how the `Gtk.WidgetClass.focus` virtual method should be implemented:

    static gboolean
    foo_focus (GtkWidget       *widget,
               GtkDirectionType direction)
    {
      Foo *self = FOO (widget);
      FooPrivate *priv = foo_get_instance_private (self);
      int focus_row = priv->focus_row;
      gboolean have_focus = FALSE;

      if (!gtk_widget_has_focus (widget))
        gtk_widget_grab_focus (widget);

      valid = gtk_tree_model_iter_nth_child (priv->model, &iter, NULL, priv->focus_row);
      while (valid)
        {
          gtk_cell_area_apply_attributes (priv->area, priv->model, &iter, FALSE, FALSE);

          if (gtk_cell_area_focus (priv->area, direction))
            {
               priv->focus_row = focus_row;
               have_focus = TRUE;
               break;
            }
          else
            {
              if (direction == GTK_DIR_RIGHT ||
                  direction == GTK_DIR_LEFT)
                break;
              else if (direction == GTK_DIR_UP ||
                       direction == GTK_DIR_TAB_BACKWARD)
               {
                  if (focus_row == 0)
                    break;
                  else
                   {
                      focus_row--;
                      valid = gtk_tree_model_iter_nth_child (priv->model, &iter, NULL, focus_row);
                   }
                }
              else
                {
                  if (focus_row == last_row)
                    break;
                  else
                    {
                      focus_row++;
                      valid = gtk_tree_model_iter_next (priv->model, &iter);
                    }
                }
            }
        }
        return have_focus;
    }

Note that the layouting widget is responsible for matching the `GtkDirectionType` values to the way it lays out its cells.

## Cell Properties

The `GtkCellArea` introduces cell properties for `GtkCellRenderer`s. This provides some general interfaces for defining the relationship cell areas have with their cells. For instance in a `GtkCellAreaBox` a cell might “expand” and receive extra space when the area is allocated more than its full natural request, or a cell might be configured to “align” with adjacent rows which were requested and rendered with the same `GtkCellAreaContext`.

Use `gtk_cell_area_class_install_cell_property()` to install cell properties for a cell area class and `gtk_cell_area_class_find_cell_property()` or `gtk_cell_area_class_list_cell_properties()` to get information about existing cell properties.

To set the value of a cell property, use `gtk_cell_area_cell_set_property()`, `gtk_cell_area_cell_set()` or `gtk_cell_area_cell_set_valist()`. To obtain the value of a cell property, use `gtk_cell_area_cell_get_property()` `gtk_cell_area_cell_get()` or `gtk_cell_area_cell_get_valist()`.

Deprecated since: 4.10

List views use widgets for displaying their contents.

#### Ancestors

- GInitiallyUnowned
- GObject

#### Descendants

- GtkCellAreaBox

#### Implements

- GtkBuildable
- GtkCellLayout

#### Instance methods

###### gtk_cell_area_activate

Activates `area`, usually by activating the currently focused cell, however some subclasses which embed widgets in the area can also activate a widget if it currently has the focus.

deprecated: 4.10

###### gtk_cell_area_activate_cell

This is used by `GtkCellArea` subclasses when handling events to activate cells, the base `GtkCellArea` class activates cells for keyboard events for free in its own GtkCellArea->activate() implementation.

deprecated: 4.10

###### gtk_cell_area_add

Adds `renderer` to `area` with the default child cell properties.

deprecated: 4.10

###### gtk_cell_area_add_focus_sibling

Adds `sibling` to `renderer`’s focusable area, focus will be drawn around `renderer` and all of its siblings if `renderer` can focus for a given row.

deprecated: 4.10

###### gtk_cell_area_add_with_properties

Adds `renderer` to `area`, setting cell properties at the same time. See `gtk_cell_area_add()` and `gtk_cell_area_cell_set()` for more details.

deprecated: 4.10

###### gtk_cell_area_apply_attributes

Applies any connected attributes to the renderers in `area` by pulling the values from `tree_model`.

deprecated: 4.10

###### gtk_cell_area_attribute_connect

Connects an `attribute` to apply values from `column` for the `GtkTreeModel` in use.

deprecated: 4.10

###### gtk_cell_area_attribute_disconnect

Disconnects `attribute` for the `renderer` in `area` so that attribute will no longer be updated with values from the model.

deprecated: 4.10

###### gtk_cell_area_attribute_get_column

Returns the model column that an attribute has been mapped to, or -1 if the attribute is not mapped.

deprecated: 4.10

###### gtk_cell_area_cell_get

Gets the values of one or more cell properties for `renderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_cell_get_property

Gets the value of a cell property for `renderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_cell_get_valist

Gets the values of one or more cell properties for `renderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_cell_set

Sets one or more cell properties for `cell` in `area`.

deprecated: 4.10

###### gtk_cell_area_cell_set_property

Sets a cell property for `renderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_cell_set_valist

Sets one or more cell properties for `renderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_copy_context

This is sometimes needed for cases where rows need to share alignments in one orientation but may be separately grouped in the opposing orientation.

deprecated: 4.10

###### gtk_cell_area_create_context

Creates a `GtkCellArea`Context to be used with `area` for all purposes. `GtkCellArea`Context stores geometry information for rows for which it was operated on, it is important to use the same context for the same row of data at all times (i.e. one should render and handle events with the same `GtkCellArea`Context which was used to request the size of those rows of data).

deprecated: 4.10

###### gtk_cell_area_event

Delegates event handling to a `GtkCellArea`.

deprecated: 4.10

###### gtk_cell_area_focus

This should be called by the `area`’s owning layout widget when focus is to be passed to `area`, or moved within `area` for a given `direction` and row data.

deprecated: 4.10

###### gtk_cell_area_foreach

Calls `callback` for every `GtkCellRenderer` in `area`.

deprecated: 4.10

###### gtk_cell_area_foreach_alloc

Calls `callback` for every `GtkCellRenderer` in `area` with the allocated rectangle inside `cell_area`.

###### gtk_cell_area_get_cell_allocation

Derives the allocation of `renderer` inside `area` if `area` were to be rendered in `cell_area`.

deprecated: 4.10

###### gtk_cell_area_get_cell_at_position

Gets the `GtkCellRenderer` at `x` and `y` coordinates inside `area` and optionally returns the full cell allocation for it inside `cell_area`.

deprecated: 4.10

###### gtk_cell_area_get_current_path_string

Gets the current `GtkTreePath` string for the currently applied `GtkTreeIter`, this is implicitly updated when `gtk_cell_area_apply_attributes()` is called and can be used to interact with renderers from `GtkCellArea` subclasses.

###### gtk_cell_area_get_edit_widget

Gets the `GtkCellEditable` widget currently used to edit the currently edited cell.

deprecated: 4.10

###### gtk_cell_area_get_edited_cell

Gets the `GtkCellRenderer` in `area` that is currently being edited.

deprecated: 4.10

###### gtk_cell_area_get_focus_cell

Retrieves the currently focused cell for `area`.

deprecated: 4.10

###### gtk_cell_area_get_focus_from_sibling

Gets the `GtkCellRenderer` which is expected to be focusable for which `renderer` is, or may be a sibling.

deprecated: 4.10

###### gtk_cell_area_get_focus_siblings

Gets the focus sibling cell renderers for `renderer`.

deprecated: 4.10

###### gtk_cell_area_get_preferred_height

Retrieves a cell area’s initial minimum and natural height.

deprecated: 4.10

###### gtk_cell_area_get_preferred_height_for_width

Retrieves a cell area’s minimum and natural height if it would be given the specified `width`.

deprecated: 4.10

###### gtk_cell_area_get_preferred_width

Retrieves a cell area’s initial minimum and natural width.

deprecated: 4.10

###### gtk_cell_area_get_preferred_width_for_height

Retrieves a cell area’s minimum and natural width if it would be given the specified `height`.

deprecated: 4.10

###### gtk_cell_area_get_request_mode

Gets whether the area prefers a height-for-width layout or a width-for-height layout.

###### gtk_cell_area_has_renderer

Checks if `area` contains `renderer`.

deprecated: 4.10

###### gtk_cell_area_inner_cell_area

This is a convenience function for `GtkCellArea` implementations to get the inner area where a given `GtkCellRenderer` will be rendered. It removes any padding previously added by gtk_cell_area_request_renderer().

deprecated: 4.10

###### gtk_cell_area_is_activatable

Returns whether the area can do anything when activated, after applying new attributes to `area`.

deprecated: 4.10

###### gtk_cell_area_is_focus_sibling

Returns whether `sibling` is one of `renderer`’s focus siblings (see gtk_cell_area_add_focus_sibling()).

deprecated: 4.10

###### gtk_cell_area_remove

Removes `renderer` from `area`.

deprecated: 4.10

###### gtk_cell_area_remove_focus_sibling

Removes `sibling` from `renderer`’s focus sibling list (see gtk_cell_area_add_focus_sibling()).

deprecated: 4.10

###### gtk_cell_area_request_renderer

This is a convenience function for `GtkCellArea` implementations to request size for cell renderers. It’s important to use this function to request size and then use `gtk_cell_area_inner_cell_area()` at render and event time since this function will add padding around the cell for focus painting.

deprecated: 4.10

###### gtk_cell_area_set_focus_cell

Explicitly sets the currently focused cell to `renderer`.

deprecated: 4.10

###### gtk_cell_area_snapshot

Snapshots `area`’s cells according to `area`’s layout onto at the given coordinates.

deprecated: 4.10

###### gtk_cell_area_stop_editing

Explicitly stops the editing of the currently edited cell.

deprecated: 4.10

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GtkBuildable (1)

###### gtk_buildable_get_buildable_id

Gets the ID of the `buildable` object.

##### Methods inherited from GtkCellLayout (10)

###### gtk_cell_layout_add_attribute

Adds an attribute mapping to the list in `cell_layout`.

deprecated: 4.10

###### gtk_cell_layout_clear

Unsets all the mappings on all renderers on `cell_layout` and removes all renderers from `cell_layout`.

deprecated: 4.10

###### gtk_cell_layout_clear_attributes

Clears all existing attributes previously set with gtk_cell_layout_set_attributes().

deprecated: 4.10

###### gtk_cell_layout_get_area

Returns the underlying `GtkCellArea` which might be `cell_layout` if called on a `GtkCellArea` or might be `NULL` if no `GtkCellArea` is used by `cell_layout`.

deprecated: 4.10

###### gtk_cell_layout_get_cells

Returns the cell renderers which have been added to `cell_layout`.

deprecated: 4.10

###### gtk_cell_layout_pack_end

Adds the `cell` to the end of `cell_layout`. If `expand` is `FALSE`, then the `cell` is allocated no more space than it needs. Any unused space is divided evenly between cells for which `expand` is `TRUE`.

deprecated: 4.10

###### gtk_cell_layout_pack_start

Packs the `cell` into the beginning of `cell_layout`. If `expand` is `FALSE`, then the `cell` is allocated no more space than it needs. Any unused space is divided evenly between cells for which `expand` is `TRUE`.

deprecated: 4.10

###### gtk_cell_layout_reorder

Re-inserts `cell` at `position`.

deprecated: 4.10

###### gtk_cell_layout_set_attributes

Sets the attributes in the parameter list as the attributes of `cell_layout`.

deprecated: 4.10

###### gtk_cell_layout_set_cell_data_func

Sets the `GtkCellLayout`DataFunc to use for `cell_layout`.

deprecated: 4.10

#### Properties

###### Gtk.CellArea:edit-widget

The widget currently editing the edited cell.

###### Gtk.CellArea:edited-cell

The cell in the area that is currently edited.

###### Gtk.CellArea:focus-cell

The cell in the area that currently has focus.

#### Signals

###### Gtk.CellArea::add-editable

Indicates that editing has started on `renderer` and that `editable` should be added to the owning cell-layouting widget at `cell_area`.

###### Gtk.CellArea::apply-attributes

This signal is emitted whenever applying attributes to `area` from `model`.

###### Gtk.CellArea::focus-changed

Indicates that focus changed on this `area`. This signal is emitted either as a result of focus handling or event handling.

###### Gtk.CellArea::remove-editable

Indicates that editing finished on `renderer` and that `editable` should be removed from the owning cell-layouting widget.

##### Signals inherited from GObject (1)

###### GObject::notify

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.

#### Class structure

    struct GtkCellAreaClass {
      void (* add) (
        GtkCellArea* area,
        GtkCellRenderer* renderer
      );
      void (* remove) (
        GtkCellArea* area,
        GtkCellRenderer* renderer
      );
      void (* foreach) (
        GtkCellArea* area,
        GtkCellCallback callback,
        gpointer callback_data
      );
      void (* foreach_alloc) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        const GdkRectangle* cell_area,
        const GdkRectangle* background_area,
        GtkCellAllocCallback callback,
        gpointer callback_data
      );
      int (* event) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        GdkEvent* event,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      );
      void (* snapshot) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        GtkSnapshot* snapshot,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags,
        gboolean paint_focus
      );
      void (* apply_attributes) (
        GtkCellArea* area,
        GtkTreeModel* tree_model,
        GtkTreeIter* iter,
        gboolean is_expander,
        gboolean is_expanded
      );
      GtkCellAreaContext* (* create_context) (
        GtkCellArea* area
      );
      GtkCellAreaContext* (* copy_context) (
        GtkCellArea* area,
        GtkCellAreaContext* context
      );
      GtkSizeRequestMode (* get_request_mode) (
        GtkCellArea* area
      );
      void (* get_preferred_width) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        int* minimum_width,
        int* natural_width
      );
      void (* get_preferred_height_for_width) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        int width,
        int* minimum_height,
        int* natural_height
      );
      void (* get_preferred_height) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        int* minimum_height,
        int* natural_height
      );
      void (* get_preferred_width_for_height) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        int height,
        int* minimum_width,
        int* natural_width
      );
      void (* set_cell_property) (
        GtkCellArea* area,
        GtkCellRenderer* renderer,
        guint property_id,
        const GValue* value,
        GParamSpec* pspec
      );
      void (* get_cell_property) (
        GtkCellArea* area,
        GtkCellRenderer* renderer,
        guint property_id,
        GValue* value,
        GParamSpec* pspec
      );
      gboolean (* focus) (
        GtkCellArea* area,
        GtkDirectionType direction
      );
      gboolean (* is_activatable) (
        GtkCellArea* area
      );
      gboolean (* activate) (
        GtkCellArea* area,
        GtkCellAreaContext* context,
        GtkWidget* widget,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags,
        gboolean edit_only
      );

    }

No description available.

###### Class members

`add: void (* add) ( GtkCellArea* area, GtkCellRenderer* renderer )`

  Adds a `GtkCellRenderer` to the area.

`remove: void (* remove) ( GtkCellArea* area, GtkCellRenderer* renderer )`

  Removes a `GtkCellRenderer` from the area.

`foreach: void (* foreach) ( GtkCellArea* area, GtkCellCallback callback, gpointer callback_data )`

  Calls the `GtkCellCallback` function on every `GtkCellRenderer` in the area with the provided user data until the callback returns `TRUE`.

`foreach_alloc: void (* foreach_alloc) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, const GdkRectangle* cell_area, const GdkRectangle* background_area, GtkCellAllocCallback callback, gpointer callback_data )`

  Calls the `GtkCellAllocCallback` function on every `GtkCellRenderer` in the area with the allocated area for the cell and the provided user data until the callback returns `TRUE`.

`event: int (* event) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, GdkEvent* event, const GdkRectangle* cell_area, GtkCellRendererState flags )`

  Handle an event in the area, this is generally used to activate a cell at the event location for button events but can also be used to generically pass events to `GtkWidget`s drawn onto the area.

`snapshot: void (* snapshot) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, GtkSnapshot* snapshot, const GdkRectangle* background_area, const GdkRectangle* cell_area, GtkCellRendererState flags, gboolean paint_focus )`

  Actually snapshot the area’s cells to the specified rectangle, `background_area` should be correctly distributed to the cells corresponding background areas.

`apply_attributes: void (* apply_attributes) ( GtkCellArea* area, GtkTreeModel* tree_model, GtkTreeIter* iter, gboolean is_expander, gboolean is_expanded )`

  Apply the cell attributes to the cells. This is implemented as a signal and generally `GtkCellArea` subclasses don’t need to implement it since it is handled by the base class.

`create_context: GtkCellAreaContext* (* create_context) ( GtkCellArea* area )`

  Creates and returns a class specific `GtkCellAreaContext` to store cell alignment and allocation details for a said `GtkCellArea` class.

`copy_context: GtkCellAreaContext* (* copy_context) ( GtkCellArea* area, GtkCellAreaContext* context )`

  Creates a new `GtkCellAreaContext` in the same state as the passed `context` with any cell alignment data and allocations intact.

`get_request_mode: GtkSizeRequestMode (* get_request_mode) ( GtkCellArea* area )`

  This allows an area to tell its layouting widget whether it prefers to be allocated in `GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH` or `GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT` mode.

`get_preferred_width: void (* get_preferred_width) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, int* minimum_width, int* natural_width )`

  Calculates the minimum and natural width of the areas cells with the current attributes applied while considering the particular layouting details of the said `GtkCellArea`. While requests are performed over a series of rows, alignments and overall minimum and natural sizes should be stored in the corresponding `GtkCellAreaContext`.

`get_preferred_height_for_width: void (* get_preferred_height_for_width) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, int width, int* minimum_height, int* natural_height )`

  Calculates the minimum and natural height for the area if the passed `context` would be allocated the given width. When implementing this virtual method it is safe to assume that `context` has already stored the aligned cell widths for every `GtkTreeModel` row that `context` will be allocated for since this information was stored at `GtkCellAreaClass.get_preferred_width()` time. This virtual method should also store any necessary alignments of cell heights for the case that the context is allocated a height.

`get_preferred_height: void (* get_preferred_height) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, int* minimum_height, int* natural_height )`

  Calculates the minimum and natural height of the areas cells with the current attributes applied. Essentially this is the same as `GtkCellAreaClass.get_preferred_width()` only for areas that are being requested as `GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT`.

`get_preferred_width_for_height: void (* get_preferred_width_for_height) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, int height, int* minimum_width, int* natural_width )`

  Calculates the minimum and natural width for the area if the passed `context` would be allocated the given height. The same as `GtkCellAreaClass.get_preferred_height_for_width()` only for handling requests in the `GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT` mode.

`set_cell_property: void (* set_cell_property) ( GtkCellArea* area, GtkCellRenderer* renderer, guint property_id, const GValue* value, GParamSpec* pspec )`

  This should be implemented to handle changes in child cell properties for a given `GtkCellRenderer` that were previously installed on the `GtkCellAreaClass` with gtk_cell_area_class_install_cell_property().

`get_cell_property: void (* get_cell_property) ( GtkCellArea* area, GtkCellRenderer* renderer, guint property_id, GValue* value, GParamSpec* pspec )`

  This should be implemented to report the values of child cell properties for a given child `GtkCellRenderer`.

`focus: gboolean (* focus) ( GtkCellArea* area, GtkDirectionType direction )`

  This virtual method should be implemented to navigate focus from cell to cell inside the `GtkCellArea`. The `GtkCellArea` should move focus from cell to cell inside the area and return `FALSE` if focus logically leaves the area with the following exceptions: When the area contains no activatable cells, the entire area receives focus. Focus should not be given to cells that are actually “focus siblings” of other sibling cells (see gtk_cell_area_get_focus_from_sibling()). Focus is set by calling gtk_cell_area_set_focus_cell().

`is_activatable: gboolean (* is_activatable) ( GtkCellArea* area )`

  Returns whether the `GtkCellArea` can respond to `GtkCellAreaClass.activate()`, usually this does not need to be implemented since the base class takes care of this however it can be enhanced if the `GtkCellArea` subclass can handle activation in other ways than activating its `GtkCellRenderers`.

`activate: gboolean (* activate) ( GtkCellArea* area, GtkCellAreaContext* context, GtkWidget* widget, const GdkRectangle* cell_area, GtkCellRendererState flags, gboolean edit_only )`

  This is called when the layouting widget rendering the `GtkCellArea` activates the focus cell (see gtk_cell_area_get_focus_cell()).

#### Virtual methods

###### Gtk.CellAreaClass.activate

Activates `area`, usually by activating the currently focused cell, however some subclasses which embed widgets in the area can also activate a widget if it currently has the focus.

deprecated: 4.10

###### Gtk.CellAreaClass.add

Adds `renderer` to `area` with the default child cell properties.

deprecated: 4.10

###### Gtk.CellAreaClass.apply_attributes

Applies any connected attributes to the renderers in `area` by pulling the values from `tree_model`.

deprecated: 4.10

###### Gtk.CellAreaClass.copy_context

This is sometimes needed for cases where rows need to share alignments in one orientation but may be separately grouped in the opposing orientation.

deprecated: 4.10

###### Gtk.CellAreaClass.create_context

Creates a `GtkCellArea`Context to be used with `area` for all purposes. `GtkCellArea`Context stores geometry information for rows for which it was operated on, it is important to use the same context for the same row of data at all times (i.e. one should render and handle events with the same `GtkCellArea`Context which was used to request the size of those rows of data).

deprecated: 4.10

###### Gtk.CellAreaClass.event

Delegates event handling to a `GtkCellArea`.

deprecated: 4.10

###### Gtk.CellAreaClass.focus

This should be called by the `area`’s owning layout widget when focus is to be passed to `area`, or moved within `area` for a given `direction` and row data.

deprecated: 4.10

###### Gtk.CellAreaClass.foreach

Calls `callback` for every `GtkCellRenderer` in `area`.

deprecated: 4.10

###### Gtk.CellAreaClass.foreach_alloc

Calls `callback` for every `GtkCellRenderer` in `area` with the allocated rectangle inside `cell_area`.

###### Gtk.CellAreaClass.get_cell_property

This should be implemented to report the values of child cell properties for a given child `GtkCellRenderer`.

###### Gtk.CellAreaClass.get_preferred_height

Retrieves a cell area’s initial minimum and natural height.

deprecated: 4.10

###### Gtk.CellAreaClass.get_preferred_height_for_width

Retrieves a cell area’s minimum and natural height if it would be given the specified `width`.

deprecated: 4.10

###### Gtk.CellAreaClass.get_preferred_width

Retrieves a cell area’s initial minimum and natural width.

deprecated: 4.10

###### Gtk.CellAreaClass.get_preferred_width_for_height

Retrieves a cell area’s minimum and natural width if it would be given the specified `height`.

deprecated: 4.10

###### Gtk.CellAreaClass.get_request_mode

Gets whether the area prefers a height-for-width layout or a width-for-height layout.

###### Gtk.CellAreaClass.is_activatable

Returns whether the area can do anything when activated, after applying new attributes to `area`.

deprecated: 4.10

###### Gtk.CellAreaClass.remove

Removes `renderer` from `area`.

deprecated: 4.10

###### Gtk.CellAreaClass.set_cell_property

This should be implemented to handle changes in child cell properties for a given `GtkCellRenderer` that were previously installed on the `GtkCellAreaClass` with gtk_cell_area_class_install_cell_property().

###### Gtk.CellAreaClass.snapshot

Snapshots `area`’s cells according to `area`’s layout onto at the given coordinates.

deprecated: 4.10

#### Class methods

###### gtk_cell_area_class_find_cell_property

Finds a cell property of a cell area class by name.

deprecated: 4.10

###### gtk_cell_area_class_install_cell_property

Installs a cell property on a cell area class.

deprecated: 4.10

###### gtk_cell_area_class_list_cell_properties

Returns all cell properties of a cell area class.

deprecated: 4.10