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Functions
void | (*GtkCellLayoutDataFunc) () |
void | gtk_cell_layout_pack_start () |
void | gtk_cell_layout_pack_end () |
GtkCellArea * | gtk_cell_layout_get_area () |
GList * | gtk_cell_layout_get_cells () |
void | gtk_cell_layout_reorder () |
void | gtk_cell_layout_clear () |
void | gtk_cell_layout_set_attributes () |
void | gtk_cell_layout_add_attribute () |
void | gtk_cell_layout_set_cell_data_func () |
void | gtk_cell_layout_clear_attributes () |
Known Implementations
GtkCellLayout is implemented by GtkAppChooserButton, GtkCellArea, GtkCellAreaBox, GtkCellView, GtkComboBox, GtkComboBoxText, GtkEntryCompletion, GtkIconView and GtkTreeViewColumn.
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, 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.
This is an example of a UI definition fragment specifying attributes:
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<object class="GtkCellView"> <child> <object class="GtkCellRendererText"/> <attributes> <attribute name="text">0</attribute> </attributes> </child>" </object> |
Furthermore for implementations of GtkCellLayout that use a GtkCellArea to lay out cells (all GtkCellLayouts in GTK+ use a GtkCellArea) cell properties can also be defined in the format by specifying the custom <cell-packing> attribute which can contain multiple <property> elements defined in the normal way.
Here is a UI definition fragment specifying cell properties:
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<object class="GtkTreeViewColumn"> <child> <object class="GtkCellRendererText"/> <cell-packing> <property name="align">True</property> <property name="expand">False</property> </cell-packing> </child>" </object> |
Subclassing GtkCellLayout implementations
When subclassing a widget that implements GtkCellLayout like GtkIconView or GtkComboBox, there are some considerations related to the fact that these widgets internally use a GtkCellArea. The cell area is exposed as a construct-only property by these widgets. This means that it is possible to e.g. do
1 |
combo = g_object_new (GTK_TYPE_COMBO_BOX, "cell-area", my_cell_area, NULL); |
to use a custom cell area with a combo box. But construct properties
are only initialized after instance init()
functions have run, which means that using functions which rely on
the existence of the cell area in your subclass’ init()
function will
cause the default cell area to be instantiated. In this case, a provided
construct property value will be ignored (with a warning, to alert
you to the problem).
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static void my_combo_box_init (MyComboBox *b) { GtkCellRenderer *cell; cell = gtk_cell_renderer_pixbuf_new (); // The following call causes the default cell area for combo boxes, // a GtkCellAreaBox, to be instantiated gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (b), cell, FALSE); ... } GtkWidget * my_combo_box_new (GtkCellArea *area) { // This call is going to cause a warning about area being ignored return g_object_new (MY_TYPE_COMBO_BOX, "cell-area", area, NULL); } |
If supporting alternative cell areas with your derived widget is
not important, then this does not have to concern you. If you want
to support alternative cell areas, you can do so by moving the
problematic calls out of init()
and into a constructor()
for your class.
Functions
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.
Parameters
cell_layout |
||
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 |
[closure] |
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.
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.
Since: 2.4
gtk_cell_layout_get_area ()
GtkCellArea *
gtk_cell_layout_get_area (GtkCellLayout *cell_layout
);
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
.
Returns
the cell area used by cell_layout
,
or NULL
in case no cell area is used.
[transfer none][nullable]
Since: 3.0
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
.
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.
[element-type GtkCellRenderer][transfer container]
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.
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
.
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.
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.
Parameters
cell_layout |
||
cell |
||
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 a previously set function.
Parameters
cell_layout |
||
cell |
||
func |
the GtkCellLayoutDataFunc to use, or |
[allow-none] |
func_data |
user data for |
[closure] |
destroy |
destroy notify for |
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()
.
Since: 2.4
Types and Values
struct GtkCellLayoutIface
struct GtkCellLayoutIface { /* 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); GtkCellArea *(* get_area) (GtkCellLayout *cell_layout); };
Members
Packs the cell into the beginning of cell_layout. |
||
Adds the cell to the end of cell_layout. |
||
Unsets all the mappings on all renderers on cell_layout and removes all renderers from cell_layout. |
||
Adds an attribute mapping to the list in cell_layout. |
||
Sets the GtkCellLayoutDataFunc to use for cell_layout. |
||
Clears all existing attributes previously set
with |
||
Re-inserts cell at position. |
||
Get the cell renderers which have been added to cell_layout. |
||
Get 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. |