Interfacing Raku to Gnome GTK+

Gnome::Gtk3::CellLayout

An interface for packing cells

Description

Gnome::Gtk3::CellLayout is an interface to be implemented by all objects which want to provide a Gnome::Gtk3::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 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 (Gnome::Gtk3::CellView, Gnome::Gtk3::IconView, Gnome::Gtk3::ComboBox, Gnome::Gtk3::EntryCompletion, Gnome::Gtk3::TreeViewColumn) accept GtkCellRenderer objects as elements in UI definitions. They support a custom element for their children, which can contain multiple elements. Each 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:

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

Furthermore for implementations of GtkCellLayout that use a Gnome::Gtk3::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 attribute which can contain multiple 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>

Synopsis

Declaration

unit role Gnome::Gtk3::CellLayout;

Methods

add-attribute

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 Gnome::Gtk3::CellRendererText get its values from column 2.

method add-attribute ( N-GObject() $cell, Str $attribute, Int $column )

  • $cell; a Gnome::Gtk3::CellRenderer

  • $attribute; an attribute on the renderer

  • $column; the column position on the model to get the attribute from

clear

Unsets all the mappings on all renderers on cell-layout and removes all renderers from cell-layout.

method clear ( )

clear-attributes

Clears all existing attributes previously set with set-attributes().

method clear-attributes ( N-GObject() $cell )
  • $cell; a Gnome::Gtk3::CellRenderer to clear the attribute mapping on

get-area

Returns the underlying Gnome::Gtk3::CellArea which might be cell-layout if called on a Gnome::Gtk3::CellArea or might be undefined if no Gnome::Gtk3::CellArea is used by cell-layout.

Returns: the cell area used by cell-layout, or undefined in case no cell area is used.

method get-area ( --> N-GObject )

get-cells

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.

method get-cells ( --> Gnome::Glib::List )

pack-end

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.

method pack-end ( N-GObject() $cell, Bool $expand )

  • $cell; a Gnome::Gtk3::CellRenderer

  • $expand; True if cell is to be given extra space allocated to cell-layout

pack-start

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.

method pack-start ( N-GObject() $cell, Bool $expand )

  • $cell; a Gnome::Gtk3::CellRenderer

  • $expand; True if cell is to be given extra space allocated to cell-layout

reorder

Re-inserts cell at position.

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

method reorder ( N-GObject() $cell, Int $position )

  • $cell; a Gnome::Gtk3::CellRenderer to reorder

  • $position; new position to insert cell at