Gtk.DrawingArea
Description: Reference for Gtk.DrawingArea

### Class

# GtkDrawingArea

#### Description [src]

    class Gtk.DrawingArea : Gtk.Widget
      implements Gtk.Accessible, Gtk.Buildable, Gtk.ConstraintTarget {
      /* No available fields */
    }

Allows drawing with cairo.

It’s essentially a blank widget; you can draw on it. After creating a drawing area, the application may want to connect to:

- The `GtkWidget::realize` signal to take any necessary actions when the widget is instantiated on a particular display. (Create GDK resources in response to this signal.)

- The `GtkDrawingArea::resize` signal to take any necessary actions when the widget changes size.

- Call `gtk_drawing_area_set_draw_func()` to handle redrawing the contents of the widget.

The following code portion demonstrates using a drawing area to display a circle in the normal widget foreground color.

## Simple GtkDrawingArea usage

    static void
    draw_function (GtkDrawingArea *area,
                   cairo_t        *cr,
                   int             width,
                   int             height,
                   gpointer        data)
    {
      GdkRGBA color;

      cairo_arc (cr,
                 width / 2.0, height / 2.0,
                 MIN (width, height) / 2.0,
                 0, 2 * G_PI);

      gtk_widget_get_color (GTK_WIDGET (area),
                            &color);
      gdk_cairo_set_source_rgba (cr, &color);

      cairo_fill (cr);
    }

    int
    main (int argc, char **argv)
    {
      gtk_init ();

      GtkWidget *area = gtk_drawing_area_new ();
      gtk_drawing_area_set_content_width (GTK_DRAWING_AREA (area), 100);
      gtk_drawing_area_set_content_height (GTK_DRAWING_AREA (area), 100);
      gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (area),
                                      draw_function,
                                      NULL, NULL);
      return 0;
    }

The draw function is normally called when a drawing area first comes onscreen, or when it’s covered by another window and then uncovered. You can also force a redraw by adding to the “damage region” of the drawing area’s window using `gtk_widget_queue_draw()`. This will cause the drawing area to call the draw function again.

The available routines for drawing are documented in the Cairo documentation; GDK offers additional API to integrate with Cairo, like `gdk_cairo_set_source_rgba()` or `gdk_cairo_set_source_pixbuf()`.

To receive mouse events on a drawing area, you will need to use event controllers. To receive keyboard events, you will need to set the “can-focus” property on the drawing area, and you should probably draw some user-visible indication that the drawing area is focused.

If you need more complex control over your widget, you should consider creating your own `GtkWidget` subclass.

#### Hierarchy

#### Ancestors

- GtkWidget
- GInitiallyUnowned
- GObject

#### Implements

- GtkAccessible
- GtkBuildable
- GtkConstraintTarget

#### Constructors

###### gtk_drawing_area_new

Creates a new drawing area.

#### Instance methods

###### gtk_drawing_area_get_content_height

Retrieves the content height of the `GtkDrawingArea`.

###### gtk_drawing_area_get_content_width

Retrieves the content width of the `GtkDrawingArea`.

###### gtk_drawing_area_set_content_height

Sets the desired height of the contents of the drawing area.

###### gtk_drawing_area_set_content_width

Sets the desired width of the contents of the drawing area.

###### gtk_drawing_area_set_draw_func

Setting a draw function is the main thing you want to do when using a drawing area.

##### Methods inherited from GtkWidget (164)

Please see GtkWidget for a full list of methods.

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GtkAccessible (21)

###### gtk_accessible_announce

Requests the user’s screen reader to announce the given message.

since: 4.14

###### gtk_accessible_get_accessible_id

Retrieves the accessible identifier for the accessible object.

since: 4.22

###### gtk_accessible_get_accessible_parent

Retrieves the accessible parent for an accessible object.

since: 4.10

###### gtk_accessible_get_accessible_role

Retrieves the accessible role of an accessible object.

###### gtk_accessible_get_at_context

Retrieves the implementation for the given accessible object.

since: 4.10

###### gtk_accessible_get_bounds

Queries the coordinates and dimensions of this accessible.

since: 4.10

###### gtk_accessible_get_first_accessible_child

Retrieves the first accessible child of an accessible object.

since: 4.10

###### gtk_accessible_get_next_accessible_sibling

Retrieves the next accessible sibling of an accessible object.

since: 4.10

###### gtk_accessible_get_platform_state

Queries a platform state, such as focus.

since: 4.10

###### gtk_accessible_reset_property

Resets the accessible property to its default value.

###### gtk_accessible_reset_relation

Resets the accessible relation to its default value.

###### gtk_accessible_reset_state

Resets the accessible state to its default value.

###### gtk_accessible_set_accessible_parent

Sets the parent and sibling of an accessible object.

since: 4.10

###### gtk_accessible_update_next_accessible_sibling

Updates the next accessible sibling.

since: 4.10

###### gtk_accessible_update_platform_state

Informs ATs that the platform state has changed.

since: 4.18

###### gtk_accessible_update_property

Updates a list of accessible properties.

###### gtk_accessible_update_property_value

Updates an array of accessible properties.

###### gtk_accessible_update_relation

Updates a list of accessible relations.

###### gtk_accessible_update_relation_value

Updates an array of accessible relations.

###### gtk_accessible_update_state

Updates a list of accessible states.

###### gtk_accessible_update_state_value

Updates an array of accessible states.

##### Methods inherited from GtkBuildable (1)

###### gtk_buildable_get_buildable_id

Gets the ID of the `buildable` object.

#### Properties

###### Gtk.DrawingArea:content-height

The content height.

###### Gtk.DrawingArea:content-width

The content width.

##### Properties inherited from GtkWidget (35)

###### Gtk.Widget:can-focus

Whether the widget or any of its descendents can accept the input focus.

###### Gtk.Widget:can-target

Whether the widget can receive pointer events.

###### Gtk.Widget:css-classes

A list of css classes applied to this widget.

###### Gtk.Widget:css-name

The name of this widget in the CSS tree.

###### Gtk.Widget:cursor

The cursor used by `widget`.

###### Gtk.Widget:focus-on-click

Whether the widget should grab focus when it is clicked with the mouse.

###### Gtk.Widget:focusable

Whether this widget itself will accept the input focus.

###### Gtk.Widget:halign

How to distribute horizontal space if widget gets extra space.

###### Gtk.Widget:has-default

Whether the widget is the default widget.

###### Gtk.Widget:has-focus

Whether the widget has the input focus.

###### Gtk.Widget:has-tooltip

Enables or disables the emission of the `GtkWidget::query-tooltip` signal on `widget`.

###### Gtk.Widget:height-request

Overrides for height request of the widget.

###### Gtk.Widget:hexpand

Whether to expand horizontally.

###### Gtk.Widget:hexpand-set

Whether to use the `hexpand` property.

###### Gtk.Widget:layout-manager

The `GtkLayoutManager` instance to use to compute the preferred size of the widget, and allocate its children.

###### Gtk.Widget:limit-events

Makes this widget act like a modal dialog, with respect to event delivery.

since: 4.18

###### Gtk.Widget:margin-bottom

Margin on bottom side of widget.

###### Gtk.Widget:margin-end

Margin on end of widget, horizontally.

###### Gtk.Widget:margin-start

Margin on start of widget, horizontally.

###### Gtk.Widget:margin-top

Margin on top side of widget.

###### Gtk.Widget:name

The name of the widget.

###### Gtk.Widget:opacity

The requested opacity of the widget.

###### Gtk.Widget:overflow

How content outside the widget’s content area is treated.

###### Gtk.Widget:parent

The parent widget of this widget.

###### Gtk.Widget:receives-default

Whether the widget will receive the default action when it is focused.

###### Gtk.Widget:root

The `GtkRoot` widget of the widget tree containing this widget.

###### Gtk.Widget:scale-factor

The scale factor of the widget.

###### Gtk.Widget:sensitive

Whether the widget responds to input.

###### Gtk.Widget:tooltip-markup

Sets the text of tooltip to be the given string, which is marked up with Pango markup.

###### Gtk.Widget:tooltip-text

Sets the text of tooltip to be the given string.

###### Gtk.Widget:valign

How to distribute vertical space if widget gets extra space.

###### Gtk.Widget:vexpand

Whether to expand vertically.

###### Gtk.Widget:vexpand-set

Whether to use the `vexpand` property.

###### Gtk.Widget:visible

Whether the widget is visible.

###### Gtk.Widget:width-request

Overrides for width request of the widget.

##### Properties inherited from GtkAccessible (1)

###### GtkAccessible:accessible-role

The accessible role of the given `GtkAccessible` implementation.

#### Signals

###### Gtk.DrawingArea::resize

Emitted once when the widget is realized, and then each time the widget is changed while realized.

##### Signals inherited from GtkWidget (13)

###### GtkWidget::destroy

Signals that all holders of a reference to the widget should release the reference that they hold.

###### GtkWidget::direction-changed

Emitted when the text direction of a widget changes.

###### GtkWidget::hide

Emitted when `widget` is hidden.

###### GtkWidget::keynav-failed

Emitted if keyboard navigation fails.

###### GtkWidget::map

Emitted when `widget` is going to be mapped.

###### GtkWidget::mnemonic-activate

Emitted when a widget is activated via a mnemonic.

###### GtkWidget::move-focus

Emitted when the focus is moved.

###### GtkWidget::query-tooltip

Emitted when the widget’s tooltip is about to be shown.

###### GtkWidget::realize

Emitted when `widget` is associated with a `GdkSurface`.

###### GtkWidget::show

Emitted when `widget` is shown.

###### GtkWidget::state-flags-changed

Emitted when the widget state changes.

###### GtkWidget::unmap

Emitted when `widget` is going to be unmapped.

###### GtkWidget::unrealize

Emitted when the `GdkSurface` associated with `widget` is destroyed.

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

#### Class structure

    struct GtkDrawingAreaClass {
      GtkWidgetClass parent_class;
      void (* resize) (
        GtkDrawingArea* area,
        int width,
        int height
      );

    }

No description available.

###### Class members

`parent_class: GtkWidgetClass`

  No description available.

`resize: void (* resize) ( GtkDrawingArea* area, int width, int height )`

  No description available.

#### Virtual methods

###### Gtk.DrawingAreaClass.resize

No description available.