Gtk.CellRenderer
Description: Reference for Gtk.CellRenderer

### Class

# GtkCellRenderer

#### Description [src]

    abstract class Gtk.CellRenderer : GObject.InitiallyUnowned {
      parent_instance: GInitiallyUnowned
    }

An object for rendering a single cell

The `GtkCellRenderer` is a base class of a set of objects used for rendering a cell to a `cairo_t`. These objects are used primarily by the `GtkTreeView` widget, though they aren’t tied to them in any specific way. It is worth noting that `GtkCellRenderer` is not a `GtkWidget` and cannot be treated as such.

The primary use of a `GtkCellRenderer` is for drawing a certain graphical elements on a `cairo_t`. Typically, one cell renderer is used to draw many cells on the screen. To this extent, it isn’t expected that a CellRenderer keep any permanent state around. Instead, any state is set just prior to use using `GObject`s property system. Then, the cell is measured using `gtk_cell_renderer_get_preferred_size()`. Finally, the cell is rendered in the correct location using `gtk_cell_renderer_snapshot()`.

There are a number of rules that must be followed when writing a new `GtkCellRenderer`. First and foremost, it’s important that a certain set of properties will always yield a cell renderer of the same size, barring a style change. The `GtkCellRenderer` also has a number of generic properties that are expected to be honored by all children.

Beyond merely rendering a cell, cell renderers can optionally provide active user interface elements. A cell renderer can be “activatable” like `GtkCellRenderer`Toggle, which toggles when it gets activated by a mouse click, or it can be “editable” like `GtkCellRenderer`Text, which allows the user to edit the text using a widget implementing the `GtkCellEditable` interface, e.g. `GtkEntry`. To make a cell renderer activatable or editable, you have to implement the `GtkCellRenderer`Class.activate or `GtkCellRenderer`Class.start_editing virtual functions, respectively.

Many properties of `GtkCellRenderer` and its subclasses have a corresponding “set” property, e.g. “cell-background-set” corresponds to “cell-background”. These “set” properties reflect whether a property has been set or not. You should not set them independently.

#### Ancestors

- GInitiallyUnowned
- GObject

#### Instance methods

###### gtk_cell_renderer_activate

Passes an activate event to the cell renderer for possible processing. Some cell renderers may use events; for example, `GtkCellRendererToggle` toggles when it gets a mouse click.

###### gtk_cell_renderer_get_aligned_area

Gets the aligned area used by `cell` inside `cell_area`. Used for finding the appropriate edit and focus rectangle.

###### gtk_cell_renderer_get_alignment

Fills in `xalign` and `yalign` with the appropriate values of `cell`.

###### gtk_cell_renderer_get_fixed_size

Fills in `width` and `height` with the appropriate size of `cell`.

###### gtk_cell_renderer_get_is_expanded

Checks whether the given `GtkCellRenderer` is expanded.

###### gtk_cell_renderer_get_is_expander

Checks whether the given `GtkCellRenderer` is an expander.

###### gtk_cell_renderer_get_padding

Fills in `xpad` and `ypad` with the appropriate values of `cell`.

###### gtk_cell_renderer_get_preferred_height

Retrieves a renderer’s natural size when rendered to `widget`.

###### gtk_cell_renderer_get_preferred_height_for_width

Retrieves a cell renderers’s minimum and natural height if it were rendered to `widget` with the specified `width`.

###### gtk_cell_renderer_get_preferred_size

Retrieves the minimum and natural size of a cell taking into account the widget’s preference for height-for-width management.

###### gtk_cell_renderer_get_preferred_width

Retrieves a renderer’s natural size when rendered to `widget`.

###### gtk_cell_renderer_get_preferred_width_for_height

Retrieves a cell renderers’s minimum and natural width if it were rendered to `widget` with the specified `height`.

###### gtk_cell_renderer_get_request_mode

Gets whether the cell renderer prefers a height-for-width layout or a width-for-height layout.

###### gtk_cell_renderer_get_sensitive

Returns the cell renderer’s sensitivity.

###### gtk_cell_renderer_get_state

Translates the cell renderer state to `GtkStateFlags`, based on the cell renderer and widget sensitivity, and the given `GtkCellRenderer`State.

###### gtk_cell_renderer_get_visible

Returns the cell renderer’s visibility.

###### gtk_cell_renderer_is_activatable

Checks whether the cell renderer can do something when activated.

###### gtk_cell_renderer_set_alignment

Sets the renderer’s alignment within its available space.

###### gtk_cell_renderer_set_fixed_size

Sets the renderer size to be explicit, independent of the properties set.

###### gtk_cell_renderer_set_is_expanded

Sets whether the given `GtkCellRenderer` is expanded.

###### gtk_cell_renderer_set_is_expander

Sets whether the given `GtkCellRenderer` is an expander.

###### gtk_cell_renderer_set_padding

Sets the renderer’s padding.

###### gtk_cell_renderer_set_sensitive

Sets the cell renderer’s sensitivity.

###### gtk_cell_renderer_set_visible

Sets the cell renderer’s visibility.

###### gtk_cell_renderer_snapshot

Invokes the virtual render function of the `GtkCellRenderer`. The three passed-in rectangles are areas in `cr`. Most renderers will draw within `cell_area`; the xalign, yalign, xpad, and ypad fields of the `GtkCellRenderer` should be honored with respect to `cell_area`. `background_area` includes the blank space around the cell, and also the area containing the tree expander; so the `background_area` rectangles for all cells tile to cover the entire `window`.

###### gtk_cell_renderer_start_editing

Starts editing the contents of this `cell`, through a new `GtkCellEditable` widget created by the `GtkCellRenderer`Class.start_editing virtual function.

###### gtk_cell_renderer_stop_editing

Informs the cell renderer that the editing is stopped. If `canceled` is `TRUE`, the cell renderer will emit the `GtkCellRenderer`::editing-canceled signal.

#### Properties

###### Gtk.CellRenderer:cell-background

No description available.

###### Gtk.CellRenderer:cell-background-rgba

Cell background as a `GdkRGBA`

###### Gtk.CellRenderer:cell-background-set

No description available.

###### Gtk.CellRenderer:editing

No description available.

###### Gtk.CellRenderer:height

No description available.

###### Gtk.CellRenderer:is-expanded

No description available.

###### Gtk.CellRenderer:is-expander

No description available.

###### Gtk.CellRenderer:mode

No description available.

###### Gtk.CellRenderer:sensitive

No description available.

###### Gtk.CellRenderer:visible

No description available.

###### Gtk.CellRenderer:width

No description available.

###### Gtk.CellRenderer:xalign

No description available.

###### Gtk.CellRenderer:xpad

No description available.

###### Gtk.CellRenderer:yalign

No description available.

###### Gtk.CellRenderer:ypad

No description available.

#### Signals

###### Gtk.CellRenderer::editing-canceled

This signal gets emitted when the user cancels the process of editing a cell. For example, an editable cell renderer could be written to cancel editing when the user presses Escape.

###### Gtk.CellRenderer::editing-started

This signal gets emitted when a cell starts to be edited. The intended use of this signal is to do special setup on `editable`, e.g. adding a `GtkEntryCompletion` or setting up additional columns in a `GtkComboBox`.

#### Class structure

    struct GtkCellRendererClass {
      GtkSizeRequestMode (* get_request_mode) (
        GtkCellRenderer* cell
      );
      void (* get_preferred_width) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int* minimum_size,
        int* natural_size
      );
      void (* get_preferred_height_for_width) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int width,
        int* minimum_height,
        int* natural_height
      );
      void (* get_preferred_height) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int* minimum_size,
        int* natural_size
      );
      void (* get_preferred_width_for_height) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int height,
        int* minimum_width,
        int* natural_width
      );
      void (* get_aligned_area) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        GtkCellRendererState flags,
        const GdkRectangle* cell_area,
        GdkRectangle* aligned_area
      );
      void (* snapshot) (
        GtkCellRenderer* cell,
        GtkSnapshot* snapshot,
        GtkWidget* widget,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      );
      gboolean (* activate) (
        GtkCellRenderer* cell,
        GdkEvent* event,
        GtkWidget* widget,
        const char* path,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      );
      GtkCellEditable* (* start_editing) (
        GtkCellRenderer* cell,
        GdkEvent* event,
        GtkWidget* widget,
        const char* path,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      );
      void (* editing_canceled) (
        GtkCellRenderer* cell
      );
      void (* editing_started) (
        GtkCellRenderer* cell,
        GtkCellEditable* editable,
        const char* path
      );

    }

###### Class members

`get_request_mode` |
    GtkSizeRequestMode (* get_request_mode) (
        GtkCellRenderer* cell
      )
| No description available.
`get_preferred_width` |
    void (* get_preferred_width) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int* minimum_size,
        int* natural_size
      )
| No description available.
`get_preferred_height_for_width` |
    void (* get_preferred_height_for_width) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int width,
        int* minimum_height,
        int* natural_height
      )
| No description available.
`get_preferred_height` |
    void (* get_preferred_height) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int* minimum_size,
        int* natural_size
      )
| No description available.
`get_preferred_width_for_height` |
    void (* get_preferred_width_for_height) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        int height,
        int* minimum_width,
        int* natural_width
      )
| No description available.
`get_aligned_area` |
    void (* get_aligned_area) (
        GtkCellRenderer* cell,
        GtkWidget* widget,
        GtkCellRendererState flags,
        const GdkRectangle* cell_area,
        GdkRectangle* aligned_area
      )
| No description available.
`snapshot` |
    void (* snapshot) (
        GtkCellRenderer* cell,
        GtkSnapshot* snapshot,
        GtkWidget* widget,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      )
| No description available.
`activate` |
    gboolean (* activate) (
        GtkCellRenderer* cell,
        GdkEvent* event,
        GtkWidget* widget,
        const char* path,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      )
| No description available.
`start_editing` |
    GtkCellEditable* (* start_editing) (
        GtkCellRenderer* cell,
        GdkEvent* event,
        GtkWidget* widget,
        const char* path,
        const GdkRectangle* background_area,
        const GdkRectangle* cell_area,
        GtkCellRendererState flags
      )
| No description available.
`editing_canceled` |
    void (* editing_canceled) (
        GtkCellRenderer* cell
      )
| No description available.
`editing_started` |
    void (* editing_started) (
        GtkCellRenderer* cell,
        GtkCellEditable* editable,
        const char* path
      )
| No description available.

#### Virtual methods

###### Gtk.CellRendererClass.activate

Passes an activate event to the cell renderer for possible processing. Some cell renderers may use events; for example, `GtkCellRendererToggle` toggles when it gets a mouse click.

###### Gtk.CellRendererClass.editing_canceled

No description available.

###### Gtk.CellRendererClass.editing_started

No description available.

###### Gtk.CellRendererClass.get_aligned_area

Gets the aligned area used by `cell` inside `cell_area`. Used for finding the appropriate edit and focus rectangle.

###### Gtk.CellRendererClass.get_preferred_height

Retrieves a renderer’s natural size when rendered to `widget`.

###### Gtk.CellRendererClass.get_preferred_height_for_width

Retrieves a cell renderers’s minimum and natural height if it were rendered to `widget` with the specified `width`.

###### Gtk.CellRendererClass.get_preferred_width

Retrieves a renderer’s natural size when rendered to `widget`.

###### Gtk.CellRendererClass.get_preferred_width_for_height

Retrieves a cell renderers’s minimum and natural width if it were rendered to `widget` with the specified `height`.

###### Gtk.CellRendererClass.get_request_mode

Gets whether the cell renderer prefers a height-for-width layout or a width-for-height layout.

###### Gtk.CellRendererClass.snapshot

Invokes the virtual render function of the `GtkCellRenderer`. The three passed-in rectangles are areas in `cr`. Most renderers will draw within `cell_area`; the xalign, yalign, xpad, and ypad fields of the `GtkCellRenderer` should be honored with respect to `cell_area`. `background_area` includes the blank space around the cell, and also the area containing the tree expander; so the `background_area` rectangles for all cells tile to cover the entire `window`.

###### Gtk.CellRendererClass.start_editing

Starts editing the contents of this `cell`, through a new `GtkCellEditable` widget created by the `GtkCellRenderer`Class.start_editing virtual function.