## GtkCellLayout GtkCellLayout — An interface for packing cells |

## Synopsis

    #include <gtk/gtk.h>

                        GtkCellLayout;
                        GtkCellLayoutIface;
    void                (*GtkCellLayoutDataFunc)            (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             GtkTreeModel *tree_model,
                                                             GtkTreeIter *iter,
                                                             gpointer data);
    void                gtk_cell_layout_pack_start          (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gboolean expand);
    void                gtk_cell_layout_pack_end            (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gboolean expand);
    GList *             gtk_cell_layout_get_cells           (GtkCellLayout *cell_layout);
    void                gtk_cell_layout_reorder             (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gint position);
    void                gtk_cell_layout_clear               (GtkCellLayout *cell_layout);
    void                gtk_cell_layout_set_attributes      (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             ...);
    void                gtk_cell_layout_add_attribute       (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             const gchar *attribute,
                                                             gint column);
    void                gtk_cell_layout_set_cell_data_func  (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             GtkCellLayoutDataFunc func,
                                                             gpointer func_data,
                                                             GDestroyNotify destroy);
    void                gtk_cell_layout_clear_attributes    (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell);

## Object Hierarchy

      GInterface
       +----GtkCellLayout

## Prerequisites

GtkCellLayout requires GObject.

## Known Implementations

GtkCellLayout is implemented by GtkTreeViewColumn, GtkIconView, GtkCellView, GtkEntryCompletion, GtkComboBox and GtkComboBoxEntry.

## Description

GtkCellLayout is an interface to be implemented by all objects which want to provide a GtkTreeViewColumn-like API for packing cells, setting attributes and data funcs.

One of the notable features provided by implementations of GtkCellLayout are attributes. Attributes let you set the properties in flexible ways. They can just be set to constant values like regular properties. But they can also be mapped to a column of the underlying tree model with `gtk_cell_layout_set_attributes()`, which means that the value of the attribute can change from cell to cell as they are rendered by the cell renderer. Finally, it is possible to specify a function with `gtk_cell_layout_set_cell_data_func()` that is called to determine the value of the attribute for each cell that is rendered.

### GtkCellLayouts as GtkBuildable

Implementations of GtkCellLayout which also implement the GtkBuildable interface (GtkCellView, GtkIconView, GtkComboBox, GtkComboBoxEntry, GtkEntryCompletion, GtkTreeViewColumn) accept GtkCellRenderer objects as <child> elements in UI definitions. They support a custom <attributes> element for their children, which can contain multiple <attribute> elements. Each <attribute> element has a name attribute which specifies a property of the cell renderer; the content of the element is the attribute value.

Example 22. A UI definition fragment specifying attributes

    <object class="GtkCellView">
      <child>
        <object class="GtkCellRendererText"/>
        <attributes>
          <attribute name="text">0</attribute>
        </attributes>
      </child>"
    </object>

## Details

### GtkCellLayout

    typedef struct _GtkCellLayout GtkCellLayout;

### GtkCellLayoutIface

    typedef struct {
      GTypeInterface g_iface;

      /* Virtual Table */
      void (* pack_start)         (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell,
                                   gboolean               expand);
      void (* pack_end)           (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell,
                                   gboolean               expand);
      void (* clear)              (GtkCellLayout         *cell_layout);
      void (* add_attribute)      (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell,
                                   const gchar           *attribute,
                                   gint                   column);
      void (* set_cell_data_func) (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell,
                                   GtkCellLayoutDataFunc  func,
                                   gpointer               func_data,
                                   GDestroyNotify         destroy);
      void (* clear_attributes)   (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell);
      void (* reorder)            (GtkCellLayout         *cell_layout,
                                   GtkCellRenderer       *cell,
                                   gint                   position);
      GList* (* get_cells)        (GtkCellLayout         *cell_layout);
    } GtkCellLayoutIface;

### GtkCellLayoutDataFunc ()

    void                (*GtkCellLayoutDataFunc)            (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             GtkTreeModel *tree_model,
                                                             GtkTreeIter *iter,
                                                             gpointer data);

A function which should set the value of `cell_layout`'s cell renderer(s) as appropriate.

`cell_layout` : | a GtkCellLayout
`cell` : | the cell renderer whose value is to be set
`tree_model` : | the model
`iter` : | a GtkTreeIter indicating the row to set the value for
`data` : | user data passed to `gtk_cell_layout_set_cell_data_func()`

### gtk_cell_layout_pack_start ()

    void                gtk_cell_layout_pack_start          (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gboolean expand);

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`.

Note that reusing the same cell renderer is not supported.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer.
`expand` : | `TRUE` if `cell` is to be given extra space allocated to `cell_layout`.

Since 2.4

### gtk_cell_layout_pack_end ()

    void                gtk_cell_layout_pack_end            (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gboolean expand);

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`.

Note that reusing the same cell renderer is not supported.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer.
`expand` : | `TRUE` if `cell` is to be given extra space allocated to `cell_layout`.

Since 2.4

### gtk_cell_layout_get_cells ()

    GList *             gtk_cell_layout_get_cells           (GtkCellLayout *cell_layout);

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

`cell_layout` : | a GtkCellLayout
Returns : | a list of cell renderers. The list, but not the renderers has been newly allocated and should be freed with `g_list_free()` when no longer needed.

Since 2.12

### gtk_cell_layout_reorder ()

    void                gtk_cell_layout_reorder             (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             gint position);

Re-inserts `cell` at `position`. Note that `cell` has already to be packed into `cell_layout` for this to function properly.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer to reorder.
`position` : | New position to insert `cell` at.

Since 2.4

### gtk_cell_layout_clear ()

    void                gtk_cell_layout_clear               (GtkCellLayout *cell_layout);

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

`cell_layout` : | A GtkCellLayout.

Since 2.4

### gtk_cell_layout_set_attributes ()

    void                gtk_cell_layout_set_attributes      (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             ...);

Sets the attributes in list as the attributes of `cell_layout`. The attributes should be in attribute/column order, as in `gtk_cell_layout_add_attribute()`. All existing attributes are removed, and replaced with the new attributes.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer.
`...` : | A `NULL`-terminated list of attributes.

Since 2.4

### gtk_cell_layout_add_attribute ()

    void                gtk_cell_layout_add_attribute       (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             const gchar *attribute,
                                                             gint column);

Adds an attribute mapping to the list in `cell_layout`. The `column` is the column of the model to get a value from, and the `attribute` is the parameter on `cell` to be set from the value. So for example if column 2 of the model contains strings, you could have the "text" attribute of a GtkCellRendererText get its values from column 2.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer.
`attribute` : | An attribute on the renderer.
`column` : | The column position on the model to get the attribute from.

Since 2.4

### gtk_cell_layout_set_cell_data_func ()

    void                gtk_cell_layout_set_cell_data_func  (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell,
                                                             GtkCellLayoutDataFunc func,
                                                             gpointer func_data,
                                                             GDestroyNotify destroy);

Sets the GtkCellLayoutDataFunc to use for `cell_layout`. This function is used instead of the standard attributes mapping for setting the column value, and should set the value of `cell_layout`'s cell renderer(s) as appropriate. `func` may be `NULL` to remove and older one.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer.
`func` : | The GtkCellLayoutDataFunc to use.
`func_data` : | The user data for `func`.
`destroy` : | The destroy notification for `func_data`.

Since 2.4

### gtk_cell_layout_clear_attributes ()

    void                gtk_cell_layout_clear_attributes    (GtkCellLayout *cell_layout,
                                                             GtkCellRenderer *cell);

Clears all existing attributes previously set with `gtk_cell_layout_set_attributes()`.

`cell_layout` : | A GtkCellLayout.
`cell` : | A GtkCellRenderer to clear the attribute mapping on.

Since 2.4