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:

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GtkTreeIter iter;
gint        minimum_width;
gint        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 GtkWidgetClass.get_preferred_width() 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:

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static void
foo_get_preferred_width (GtkWidget       *widget,
                         gint            *minimum_size,
                         gint            *natural_size)
{
  Foo        *foo  = FOO (widget);
  FooPrivate *priv = foo->priv;

  foo_ensure_at_least_one_handfull_of_rows_have_been_requested (foo);

  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:

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GtkTreeIter iter;
gint        minimum_height;
gint        natural_height;
gint        full_minimum_height = 0;
gint        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 GtkWidgetClass.get_preferred_height_for_width(). 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 aquired at least for the rows in the visible area of the layouting widget they can be rendered at GtkWidgetClass.draw() time.

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

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GtkAllocation allocation;
GdkRectangle  cell_area = { 0, };
GtkTreeIter   iter;
gint          minimum_width;
gint          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 “size-allocate” time 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 “focus-changed” signal to fire; as well as “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 GtkWidgetClass.focus() virtual method. The layouting widget is always responsible for knowing where GtkTreeModel rows are rendered inside the widget, so at GtkWidgetClass.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 GtkWidgetClass.focus() virtual method should be implemented:

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

  focus_row = priv->focus_row;

  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 GtkCellRenderers in very much the same way that GtkContainer introduces child properties for GtkWidgets. 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().

GtkCellCallback ()

gboolean
(*GtkCellCallback) (GtkCellRenderer *renderer,
                    gpointer data);

The type of the callback functions used for iterating over the cell renderers of a GtkCellArea, see gtk_cell_area_foreach().

GtkCellAllocCallback ()

gboolean
(*GtkCellAllocCallback) (GtkCellRenderer *renderer,
                         const GdkRectangle *cell_area,
                         const GdkRectangle *cell_background,
                         gpointer data);

The type of the callback functions used for iterating over the cell renderers and their allocated areas inside a GtkCellArea, see gtk_cell_area_foreach_alloc().

GTK_CELL_AREA_WARN_INVALID_CELL_PROPERTY_ID()

#define             GTK_CELL_AREA_WARN_INVALID_CELL_PROPERTY_ID(object, property_id, pspec)

This macro should be used to emit a standard warning about unexpected properties in set_cell_property() and get_cell_property() implementations.

gtk_cell_area_add ()

void
gtk_cell_area_add (GtkCellArea *area,
                   GtkCellRenderer *renderer);

Adds renderer to area with the default child cell properties.

Since: 3.0

gtk_cell_area_remove ()

void
gtk_cell_area_remove (GtkCellArea *area,
                      GtkCellRenderer *renderer);

Removes renderer from area .

Since: 3.0

gtk_cell_area_has_renderer ()

gboolean
gtk_cell_area_has_renderer (GtkCellArea *area,
                            GtkCellRenderer *renderer);

Checks if area contains renderer .

Since: 3.0

gtk_cell_area_foreach ()

void
gtk_cell_area_foreach (GtkCellArea *area,
                       GtkCellCallback callback,
                       gpointer callback_data);

Calls callback for every GtkCellRenderer in area .

Since: 3.0

gtk_cell_area_foreach_alloc ()

void
gtk_cell_area_foreach_alloc (GtkCellArea *area,
                             GtkCellAreaContext *context,
                             GtkWidget *widget,
                             const GdkRectangle *cell_area,
                             const GdkRectangle *background_area,
                             GtkCellAllocCallback callback,
                             gpointer callback_data);

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

Since: 3.0

gtk_cell_area_event ()

gint
gtk_cell_area_event (GtkCellArea *area,
                     GtkCellAreaContext *context,
                     GtkWidget *widget,
                     GdkEvent *event,
                     const GdkRectangle *cell_area,
                     GtkCellRendererState flags);

Delegates event handling to a GtkCellArea.

Since: 3.0

gtk_cell_area_render ()

void
gtk_cell_area_render (GtkCellArea *area,
                      GtkCellAreaContext *context,
                      GtkWidget *widget,
                      cairo_t *cr,
                      const GdkRectangle *background_area,
                      const GdkRectangle *cell_area,
                      GtkCellRendererState flags,
                      gboolean paint_focus);

Renders area ’s cells according to area ’s layout onto widget at the given coordinates.

Since: 3.0

gtk_cell_area_get_cell_allocation ()

void
gtk_cell_area_get_cell_allocation (GtkCellArea *area,
                                   GtkCellAreaContext *context,
                                   GtkWidget *widget,
                                   GtkCellRenderer *renderer,
                                   const GdkRectangle *cell_area,
                                   GdkRectangle *allocation);

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

Since: 3.0

gtk_cell_area_get_cell_at_position ()

GtkCellRenderer *
gtk_cell_area_get_cell_at_position (GtkCellArea *area,
                                    GtkCellAreaContext *context,
                                    GtkWidget *widget,
                                    const GdkRectangle *cell_area,
                                    gint x,
                                    gint y,
                                    GdkRectangle *alloc_area);

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

Since: 3.0

gtk_cell_area_create_context ()

GtkCellAreaContext *
gtk_cell_area_create_context (GtkCellArea *area);

Creates a GtkCellAreaContext to be used with area for all purposes. GtkCellAreaContext 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 GtkCellAreaContext which was used to request the size of those rows of data).

Since: 3.0

gtk_cell_area_copy_context ()

GtkCellAreaContext *
gtk_cell_area_copy_context (GtkCellArea *area,
                            GtkCellAreaContext *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.

For instance, GtkIconView creates all icons (rows) to have the same width and the cells theirin to have the same horizontal alignments. However each row of icons may have a separate collective height. GtkIconView uses this to request the heights of each row based on a context which was already used to request all the row widths that are to be displayed.

Since: 3.0

gtk_cell_area_get_request_mode ()

GtkSizeRequestMode
gtk_cell_area_get_request_mode (GtkCellArea *area);

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

Since: 3.0

gtk_cell_area_get_preferred_width ()

void
gtk_cell_area_get_preferred_width (GtkCellArea *area,
                                   GtkCellAreaContext *context,
                                   GtkWidget *widget,
                                   gint *minimum_width,
                                   gint *natural_width);

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

area will store some geometrical information in context along the way; when requesting sizes over an arbitrary number of rows, it’s not important to check the minimum_width and natural_width of this call but rather to consult gtk_cell_area_context_get_preferred_width() after a series of requests.

Since: 3.0

gtk_cell_area_get_preferred_height_for_width ()

void
gtk_cell_area_get_preferred_height_for_width
                               (GtkCellArea *area,
                                GtkCellAreaContext *context,
                                GtkWidget *widget,
                                gint width,
                                gint *minimum_height,
                                gint *natural_height);

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

area stores some geometrical information in context along the way while calling gtk_cell_area_get_preferred_width(). It’s important to perform a series of gtk_cell_area_get_preferred_width() requests with context first and then call gtk_cell_area_get_preferred_height_for_width() on each cell area individually to get the height for width of each fully requested row.

If at some point, the width of a single row changes, it should be requested with gtk_cell_area_get_preferred_width() again and then the full width of the requested rows checked again with gtk_cell_area_context_get_preferred_width().

Since: 3.0

gtk_cell_area_get_preferred_height ()

void
gtk_cell_area_get_preferred_height (GtkCellArea *area,
                                    GtkCellAreaContext *context,
                                    GtkWidget *widget,
                                    gint *minimum_height,
                                    gint *natural_height);

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

area will store some geometrical information in context along the way; when requesting sizes over an arbitrary number of rows, it’s not important to check the minimum_height and natural_height of this call but rather to consult gtk_cell_area_context_get_preferred_height() after a series of requests.

Since: 3.0

gtk_cell_area_get_preferred_width_for_height ()

void
gtk_cell_area_get_preferred_width_for_height
                               (GtkCellArea *area,
                                GtkCellAreaContext *context,
                                GtkWidget *widget,
                                gint height,
                                gint *minimum_width,
                                gint *natural_width);

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

area stores some geometrical information in context along the way while calling gtk_cell_area_get_preferred_height(). It’s important to perform a series of gtk_cell_area_get_preferred_height() requests with context first and then call gtk_cell_area_get_preferred_width_for_height() on each cell area individually to get the height for width of each fully requested row.

If at some point, the height of a single row changes, it should be requested with gtk_cell_area_get_preferred_height() again and then the full height of the requested rows checked again with gtk_cell_area_context_get_preferred_height().

Since: 3.0

gtk_cell_area_get_current_path_string ()

const gchar *
gtk_cell_area_get_current_path_string (GtkCellArea *area);

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.

Since: 3.0

gtk_cell_area_apply_attributes ()

void
gtk_cell_area_apply_attributes (GtkCellArea *area,
                                GtkTreeModel *tree_model,
                                GtkTreeIter *iter,
                                gboolean is_expander,
                                gboolean is_expanded);

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

Since: 3.0

gtk_cell_area_attribute_connect ()

void
gtk_cell_area_attribute_connect (GtkCellArea *area,
                                 GtkCellRenderer *renderer,
                                 const gchar *attribute,
                                 gint column);

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

Since: 3.0

gtk_cell_area_attribute_disconnect ()

void
gtk_cell_area_attribute_disconnect (GtkCellArea *area,
                                    GtkCellRenderer *renderer,
                                    const gchar *attribute);

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

Since: 3.0

gtk_cell_area_attribute_get_column ()

gint
gtk_cell_area_attribute_get_column (GtkCellArea *area,
                                    GtkCellRenderer *renderer,
                                    const gchar *attribute);

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

Since: 3.14

gtk_cell_area_class_install_cell_property ()

void
gtk_cell_area_class_install_cell_property
                               (GtkCellAreaClass *aclass,
                                guint property_id,
                                GParamSpec *pspec);

Installs a cell property on a cell area class.

Since: 3.0

gtk_cell_area_class_find_cell_property ()

GParamSpec *
gtk_cell_area_class_find_cell_property
                               (GtkCellAreaClass *aclass,
                                const gchar *property_name);

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

Since: 3.0

gtk_cell_area_class_list_cell_properties ()

GParamSpec **
gtk_cell_area_class_list_cell_properties
                               (GtkCellAreaClass *aclass,
                                guint *n_properties);

Returns all cell properties of a cell area class.

Since: 3.0

gtk_cell_area_add_with_properties ()

void
gtk_cell_area_add_with_properties (GtkCellArea *area,
                                   GtkCellRenderer *renderer,
                                   const gchar *first_prop_name,
                                   ...);

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.

Since: 3.0

gtk_cell_area_cell_set ()

void
gtk_cell_area_cell_set (GtkCellArea *area,
                        GtkCellRenderer *renderer,
                        const gchar *first_prop_name,
                        ...);

Sets one or more cell properties for cell in area .

Since: 3.0

gtk_cell_area_cell_get ()

void
gtk_cell_area_cell_get (GtkCellArea *area,
                        GtkCellRenderer *renderer,
                        const gchar *first_prop_name,
                        ...);

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

Since: 3.0

gtk_cell_area_cell_set_valist ()

void
gtk_cell_area_cell_set_valist (GtkCellArea *area,
                               GtkCellRenderer *renderer,
                               const gchar *first_property_name,
                               va_list var_args);

Sets one or more cell properties for renderer in area .

Since: 3.0

gtk_cell_area_cell_get_valist ()

void
gtk_cell_area_cell_get_valist (GtkCellArea *area,
                               GtkCellRenderer *renderer,
                               const gchar *first_property_name,
                               va_list var_args);

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

Since: 3.0

gtk_cell_area_cell_set_property ()

void
gtk_cell_area_cell_set_property (GtkCellArea *area,
                                 GtkCellRenderer *renderer,
                                 const gchar *property_name,
                                 const GValue *value);

Sets a cell property for renderer in area .

Since: 3.0

gtk_cell_area_cell_get_property ()

void
gtk_cell_area_cell_get_property (GtkCellArea *area,
                                 GtkCellRenderer *renderer,
                                 const gchar *property_name,
                                 GValue *value);

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

Since: 3.0

gtk_cell_area_is_activatable ()

gboolean
gtk_cell_area_is_activatable (GtkCellArea *area);

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

Since: 3.0

gtk_cell_area_activate ()

gboolean
gtk_cell_area_activate (GtkCellArea *area,
                        GtkCellAreaContext *context,
                        GtkWidget *widget,
                        const GdkRectangle *cell_area,
                        GtkCellRendererState flags,
                        gboolean edit_only);

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.

Since: 3.0

gtk_cell_area_focus ()

gboolean
gtk_cell_area_focus (GtkCellArea *area,
                     GtkDirectionType direction);

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.

Implementing GtkCellArea classes should implement this method to receive and navigate focus in its own way particular to how it lays out cells.

Since: 3.0

gtk_cell_area_set_focus_cell ()

void
gtk_cell_area_set_focus_cell (GtkCellArea *area,
                              GtkCellRenderer *renderer);

Explicitly sets the currently focused cell to renderer .

This is generally called by implementations of GtkCellAreaClass.focus() or GtkCellAreaClass.event(), however it can also be used to implement functions such as gtk_tree_view_set_cursor_on_cell().

Since: 3.0

gtk_cell_area_get_focus_cell ()

GtkCellRenderer *
gtk_cell_area_get_focus_cell (GtkCellArea *area);

Retrieves the currently focused cell for area

Since: 3.0

gtk_cell_area_add_focus_sibling ()

void
gtk_cell_area_add_focus_sibling (GtkCellArea *area,
                                 GtkCellRenderer *renderer,
                                 GtkCellRenderer *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.

Events handled by focus siblings can also activate the given focusable renderer .

Since: 3.0

gtk_cell_area_remove_focus_sibling ()

void
gtk_cell_area_remove_focus_sibling (GtkCellArea *area,
                                    GtkCellRenderer *renderer,
                                    GtkCellRenderer *sibling);

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

Since: 3.0

gtk_cell_area_is_focus_sibling ()

gboolean
gtk_cell_area_is_focus_sibling (GtkCellArea *area,
                                GtkCellRenderer *renderer,
                                GtkCellRenderer *sibling);

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

Since: 3.0

gtk_cell_area_get_focus_siblings ()

const GList *
gtk_cell_area_get_focus_siblings (GtkCellArea *area,
                                  GtkCellRenderer *renderer);

Gets the focus sibling cell renderers for renderer .

Since: 3.0

gtk_cell_area_get_focus_from_sibling ()

GtkCellRenderer *
gtk_cell_area_get_focus_from_sibling (GtkCellArea *area,
                                      GtkCellRenderer *renderer);

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

This is handy for GtkCellArea subclasses when handling events, after determining the renderer at the event location it can then chose to activate the focus cell for which the event cell may have been a sibling.

Since: 3.0

gtk_cell_area_get_edited_cell ()

GtkCellRenderer *
gtk_cell_area_get_edited_cell (GtkCellArea *area);

Gets the GtkCellRenderer in area that is currently being edited.

Since: 3.0

gtk_cell_area_get_edit_widget ()

GtkCellEditable *
gtk_cell_area_get_edit_widget (GtkCellArea *area);

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

Since: 3.0

gtk_cell_area_activate_cell ()

gboolean
gtk_cell_area_activate_cell (GtkCellArea *area,
                             GtkWidget *widget,
                             GtkCellRenderer *renderer,
                             GdkEvent *event,
                             const GdkRectangle *cell_area,
                             GtkCellRendererState flags);

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.

Since: 3.0

gtk_cell_area_stop_editing ()

void
gtk_cell_area_stop_editing (GtkCellArea *area,
                            gboolean canceled);

Explicitly stops the editing of the currently edited cell.

If canceled is TRUE, the currently edited cell renderer will emit the ::editing-canceled signal, otherwise the the ::editing-done signal will be emitted on the current edit widget.

See gtk_cell_area_get_edited_cell() and gtk_cell_area_get_edit_widget().

Since: 3.0

gtk_cell_area_inner_cell_area ()

void
gtk_cell_area_inner_cell_area (GtkCellArea *area,
                               GtkWidget *widget,
                               const GdkRectangle *cell_area,
                               GdkRectangle *inner_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().

Since: 3.0

gtk_cell_area_request_renderer ()

void
gtk_cell_area_request_renderer (GtkCellArea *area,
                                GtkCellRenderer *renderer,
                                GtkOrientation orientation,
                                GtkWidget *widget,
                                gint for_size,
                                gint *minimum_size,
                                gint *natural_size);

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.

Since: 3.0

struct GtkCellArea

struct GtkCellArea;

struct GtkCellAreaClass

struct GtkCellAreaClass {
  /* Basic methods */
  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);
  gint               (* event)                           (GtkCellArea             *area,
                                                          GtkCellAreaContext      *context,
                                                          GtkWidget               *widget,
                                                          GdkEvent                *event,
                                                          const GdkRectangle      *cell_area,
                                                          GtkCellRendererState     flags);
  void               (* render)                          (GtkCellArea             *area,
                                                          GtkCellAreaContext      *context,
                                                          GtkWidget               *widget,
                                                          cairo_t                 *cr,
                                                          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);

  /* Geometry */
  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,
                                                          gint                    *minimum_width,
                                                          gint                    *natural_width);
  void               (* get_preferred_height_for_width)  (GtkCellArea             *area,
                                                          GtkCellAreaContext      *context,
                                                          GtkWidget               *widget,
                                                          gint                     width,
                                                          gint                    *minimum_height,
                                                          gint                    *natural_height);
  void               (* get_preferred_height)            (GtkCellArea             *area,
                                                          GtkCellAreaContext      *context,
                                                          GtkWidget               *widget,
                                                          gint                    *minimum_height,
                                                          gint                    *natural_height);
  void               (* get_preferred_width_for_height)  (GtkCellArea             *area,
                                                          GtkCellAreaContext      *context,
                                                          GtkWidget               *widget,
                                                          gint                     height,
                                                          gint                    *minimum_width,
                                                          gint                    *natural_width);

  /* Cell Properties */
  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);

  /* Focus */
  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);
};

The “edit-widget” property

  “edit-widget”              GtkCellEditable *

The widget currently editing the edited cell

This property is read-only and only changes as a result of a call gtk_cell_area_activate_cell().

Flags: Read

Since: 3.0

The “edited-cell” property

  “edited-cell”              GtkCellRenderer *

The cell in the area that is currently edited

This property is read-only and only changes as a result of a call gtk_cell_area_activate_cell().

Flags: Read

Since: 3.0

The “focus-cell” property

  “focus-cell”               GtkCellRenderer *

The cell in the area that currently has focus

Flags: Read / Write

Since: 3.0

The “add-editable” signal

void
user_function (GtkCellArea     *area,
               GtkCellRenderer *renderer,
               GtkCellEditable *editable,
               GdkRectangle    *cell_area,
               gchar           *path,
               gpointer         user_data)

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

Flags: Run First

Since: 3.0

The “apply-attributes” signal

void
user_function (GtkCellArea  *area,
               GtkTreeModel *model,
               GtkTreeIter  *iter,
               gboolean      is_expander,
               gboolean      is_expanded,
               gpointer      user_data)

This signal is emitted whenever applying attributes to area from model

Flags: Run First

Since: 3.0

The “focus-changed” signal

void
user_function (GtkCellArea     *area,
               GtkCellRenderer *renderer,
               gchar           *path,
               gpointer         user_data)

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

It's possible that the signal is emitted even if the currently focused renderer did not change, this is because focus may change to the same renderer in the same cell area for a different row of data.

Flags: Run First

Since: 3.0

The “remove-editable” signal

void
user_function (GtkCellArea     *area,
               GtkCellRenderer *renderer,
               GtkCellEditable *editable,
               gpointer         user_data)

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

Flags: Run First

Since: 3.0