Package ch.bailu.gtk.gtk

Class CellLayout

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.type.Interface
ch.bailu.gtk.gtk.CellLayout
All Implemented Interfaces:
PointerInterface
public class CellLayout extends Interface
An interface for packing cells

`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:

```xml
<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 `GtkCellLayout`s in GTK use a `GtkCellArea`)
[cell properties](class.CellArea.html#cell-properties) can also be defined
in the format by specifying the custom `<cell-packing>` attribute which can
contain multiple `<property>` elements.

Here is a UI definition fragment specifying cell properties:

```xml
<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

```c
GtkWIdget *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
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.

https://docs.gtk.org/gtk4/iface.CellLayout.html

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • addAttribute

      public void addAttribute(@Nonnull CellRenderer cell, @Nonnull Str attribute, int 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 property on @cell to be set from that 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.
      In this context "attribute" and "property" are used interchangeably.
      Parameters:
      cell - a `GtkCellRenderer`
      attribute - a property on the renderer
      column - the column position on the model to get the attribute from

    • addAttribute

      public void addAttribute(@Nonnull CellRenderer cell, String attribute, int 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 property on @cell to be set from that 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.
      In this context "attribute" and "property" are used interchangeably.
      Parameters:
      cell - a `GtkCellRenderer`
      attribute - a property on the renderer
      column - the column position on the model to get the attribute from

    • clear

      public void clear()
      Unsets all the mappings on all renderers on @cell_layout and
      removes all renderers from @cell_layout.

    • clearAttributes

      public void clearAttributes(@Nonnull CellRenderer cell)
      Clears all existing attributes previously set with
      gtk_cell_layout_set_attributes().
      Parameters:
      cell - a `GtkCellRenderer` to clear the attribute mapping on

    • getArea

      public CellArea getArea()
      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

    • getCells

      public List getCells()
      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.

    • packEnd

      public void packEnd(@Nonnull CellRenderer cell, boolean 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.
      Parameters:
      cell - a `GtkCellRenderer`
      expand - %TRUE if @cell is to be given extra space allocated to @cell_layout

    • packStart

      public void packStart(@Nonnull CellRenderer cell, boolean 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.
      Parameters:
      cell - a `GtkCellRenderer`
      expand - %TRUE if @cell is to be given extra space allocated to @cell_layout

    • reorder

      public void reorder(@Nonnull CellRenderer cell, int position)
      Re-inserts @cell at @position.

      Note that @cell has already to be packed into @cell_layout
      for this to function properly.
      Parameters:
      cell - a `GtkCellRenderer` to reorder
      position - new position to insert @cell at

    • setAttributes

      public void setAttributes(@Nonnull CellRenderer cell, Object... _elipse)
      Sets the attributes in the parameter list as the attributes
      of @cell_layout.

      See [method@Gtk.CellLayout.add_attribute] for more details.

      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.
      Parameters:
      cell - a `GtkCellRenderer`
      _elipse - a %NULL-terminated list of attributes

    • setCellDataFunc

      public void setCellDataFunc(@Nonnull CellRenderer cell, CellLayout.OnCellLayoutDataFunc func, @Nullable Pointer func_data, CellLayout.OnDestroyNotify destroy)
      Sets the `GtkCellLayout`DataFunc 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 - a `GtkCellRenderer`
      func - the `GtkCellLayout`DataFunc to use
      func_data - user data for @func
      destroy - destroy notify for @func_data

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()