GI.Gtk.Interfaces.CellLayout

CellLayout is an interface to be implemented by all objects which want to provide a TreeViewColumn 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 cellLayoutSetCellDataFunc 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 (tCellView, IconView, ComboBox, EntryCompletion, TreeViewColumn) 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: > >class="GtkCellView" > child > class="GtkCellRendererText"/ > attributes > name="text"0/attribute > /attributes > /child" >/object

Furthermore for implementations of GtkCellLayout that use a CellArea to lay out cells (all GtkCellLayouts in GTK+ use a GtkCellArea) [cell properties][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:

<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 CellLayout like IconView or ComboBox, there are some considerations related to the fact that these widgets internally use a CellArea. The cell area is exposed as a construct-only property by these widgets. This means that it is possible to e.g. do

C code

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).

C code

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.

Exported types

newtype CellLayout

Memory-managed wrapper type.

Constructors

CellLayout (ManagedPtr CellLayout)

Instances

Eq CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

Methods

(==) :: CellLayout -> CellLayout -> Bool

(/=) :: CellLayout -> CellLayout -> Bool

GObject CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

ManagedPtrNewtype CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

Methods

toManagedPtr :: CellLayout -> ManagedPtr CellLayout

TypedObject CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

Methods

glibType :: IO GType

HasParentTypes CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

IsGValue (Maybe CellLayout)

Convert CellLayout to and from GValue. See toGValue and fromGValue.

Defined in GI.Gtk.Interfaces.CellLayout

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe CellLayout -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe CellLayout)

type ParentTypes CellLayout

Defined in GI.Gtk.Interfaces.CellLayout

type ParentTypes CellLayout = '[Object]

class (GObject o, IsDescendantOf CellLayout o) => IsCellLayout o

Type class for types which can be safely cast to CellLayout, for instance with toCellLayout.

Instances

(GObject o, IsDescendantOf CellLayout o) => IsCellLayout o

Defined in GI.Gtk.Interfaces.CellLayout

toCellLayout :: (MonadIO m, IsCellLayout o) => o -> m CellLayout

Cast to CellLayout, for types for which this is known to be safe. For general casts, use castTo.

Methods

Click to display all available methods, including inherited ones

Methods

addAttribute, bindProperty, bindPropertyFull, clear, clearAttributes, forceFloating, freezeNotify, getv, isFloating, notify, notifyByPspec, packEnd, packStart, ref, refSink, reorder, runDispose, stealData, stealQdata, thawNotify, unref, watchClosure.

Getters

getArea, getCells, getData, getProperty, getQdata.

Setters

setCellDataFunc, setData, setDataFull, setProperty.

addAttribute

cellLayoutAddAttribute

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer

-> Text

attribute: an attribute on the renderer

-> Int32

column: the column position on the model to get the attribute from

-> m ()

Adds an attribute mapping to the list in cellLayout.

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 CellRendererText get its values from column 2.

Since: 2.4

clear

cellLayoutClear

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a)

=> a

cellLayout: a CellLayout

-> m ()

Unsets all the mappings on all renderers on cellLayout and removes all renderers from cellLayout.

Since: 2.4

clearAttributes

cellLayoutClearAttributes

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer to clear the attribute mapping on

-> m ()

Clears all existing attributes previously set with gtk_cell_layout_set_attributes().

Since: 2.4

getArea

cellLayoutGetArea

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a)

=> a

cellLayout: a CellLayout

-> m (Maybe CellArea)

Returns: the cell area used by cellLayout, or Nothing in case no cell area is used.

Returns the underlying CellArea which might be cellLayout if called on a CellArea or might be Nothing if no CellArea is used by cellLayout.

Since: 3.0

getCells

cellLayoutGetCells

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a)

=> a

cellLayout: a CellLayout

-> m [CellRenderer]

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.

Returns the cell renderers which have been added to cellLayout.

Since: 2.12

packEnd

cellLayoutPackEnd

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer

-> Bool

expand: True if cell is to be given extra space allocated to cellLayout

-> m ()

Adds the cell to the end of cellLayout. 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

packStart

cellLayoutPackStart

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer

-> Bool

expand: True if cell is to be given extra space allocated to cellLayout

-> m ()

Packs the cell into the beginning of cellLayout. 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

reorder

cellLayoutReorder

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer to reorder

-> Int32

position: new position to insert cell at

-> m ()

Re-inserts cell at position.

Note that cell has already to be packed into cellLayout for this to function properly.

Since: 2.4

setCellDataFunc

cellLayoutSetCellDataFunc

Arguments

:: (HasCallStack, MonadIO m, IsCellLayout a, IsCellRenderer b)

=> a

cellLayout: a CellLayout

-> b

cell: a CellRenderer

-> Maybe CellLayoutDataFunc

func: the CellLayoutDataFunc to use, or Nothing

-> m ()

Sets the CellLayoutDataFunc to use for cellLayout.

This function is used instead of the standard attributes mapping for setting the column value, and should set the value of cellLayout’s cell renderer(s) as appropriate.

func may be Nothing to remove a previously set function.

Since: 2.4