DrawingArea
GtkDrawingArea is a widget that 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 signal@Gtk.Widget::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 signal@Gtk.DrawingArea::resize signal to take any necessary actions when the widget changes size.
Call method@Gtk.DrawingArea.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 method@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 func@Gdk.cairo_set_source_rgba or func@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.
Constructors
Properties
The accessible role of the given GtkAccessible implementation.
The content height.
The content width.
A list of css classes applied to this widget.
Whether the widget should grab focus when it is clicked with the mouse.
Enables or disables the emission of the ::query-tooltip signal on @widget.
Whether to use the hexpand property.
The GtkLayoutManager instance to use to compute the preferred size of the widget, and allocate its children.
Margin on bottom side of widget.
Margin on start of widget, horizontally.
Whether the widget will receive the default action when it is focused.
The scale factor of the widget.
Sets the text of tooltip to be the given string, which is marked up with Pango markup.
Sets the text of tooltip to be the given string.
Whether to use the vexpand property.
Functions
Enable or disable an action installed with gtk_widget_class_install_action().
Looks up the action in the action groups associated with
Activates the default.activate action from @widget.
Adds @controller to @widget so that it will receive events.
Adds a style class to @widget.
Adds a widget to the list of mnemonic labels for this widget.
Queues an animation frame update and adds a callback to be called before each frame.
Requests the user's screen reader to announce the given message.
Called by widgets as the user moves around the window using keyboard shortcuts.
Computes the bounds for @widget in the coordinate space of @target.
Computes whether a container should give this widget extra space when possible.
Translates the given @point in @widget's coordinates to coordinates relative to @target’s coordinate system.
Computes a matrix suitable to describe a transformation from
Signals that all holders of a reference to the widget should release the reference that they hold.
Emitted when the text direction of a widget changes.
Emitted when @widget is hidden.
Emitted if keyboard navigation fails.
Emitted when @widget is going to be mapped.
Emitted when a widget is activated via a mnemonic.
Emitted when the focus is moved.
Emitted when @widget is associated with a GdkSurface.
Emitted once when the widget is realized, and then each time the widget is changed while realized.
Emitted when @widget is shown.
Emitted when the widget state changes.
Emitted when @widget is going to be unmapped.
Emitted when the GdkSurface associated with @widget is destroyed.
Creates a new PangoLayout with the appropriate font map, font description, and base direction for drawing text for this widget.
Clears the template children for the given widget.
Retrieves the accessible parent for an accessible object.
Retrieves the accessible role of an accessible object.
Returns the baseline that has currently been allocated to @widget.
Returns the height that has currently been allocated to @widget.
Returns the width that has currently been allocated to @widget.
Gets the first ancestor of @widget with type @widget_type.
Retrieves the accessible implementation for the given GtkAccessible.
Returns the baseline that has currently been allocated to @widget.
Gets the ID of the @buildable object.
Determines whether the input focus can enter @widget or any of its children.
Queries whether @widget can be the target of pointer events.
Gets the value set with gtk_widget_set_child_visible().
Gets the clipboard object for @widget.
Retrieves the content height of the GtkDrawingArea.
Retrieves the content width of the GtkDrawingArea.
Returns the list of style classes applied to @widget.
Returns the CSS name that is used for @self.
Gets the reading direction for a particular widget.
Get the GdkDisplay for the toplevel window associated with this widget.
Retrieves the first accessible child of an accessible object.
Returns the widget’s first child.
Determines whether @widget can own the input focus.
Returns the current focus child of @widget.
Returns whether the widget should grab focus when it is clicked with the mouse.
Gets the font map of @widget.
Obtains the frame clock for a widget.
Returns the current value of the has-tooltip property.
Gets whether the widget would like any available extra horizontal space.
Gets whether gtk_widget_set_hexpand() has been used to explicitly set the expand flag on this widget.
Returns the widget’s last child.
Retrieves the layout manager used by @widget.
Gets the bottom margin of @widget.
Gets the end margin of @widget.
Gets the start margin of @widget.
Gets the top margin of @widget.
Retrieves the next accessible sibling of an accessible object
Returns the widget’s next sibling.
#Fetches the requested opacity for this widget.
Returns the widget’s overflow value.
Query a platform state, such as focus.
Retrieves the minimum and natural size of a widget, taking into account the widget’s preference for height-for-width management.
Returns the widget’s previous sibling.
Gets the primary clipboard of @widget.
Determines whether @widget is realized.
Determines whether @widget is always treated as the default widget within its toplevel when it has the focus, even if another widget is the default.
Gets whether the widget prefers a height-for-width layout or a width-for-height layout.
Retrieves the internal scale factor that maps from window coordinates to the actual device pixels.
Returns the widget’s sensitivity.
Gets the settings object holding the settings used for this widget.
Returns the content width or height of the widget.
Returns the widget state as a flag set.
Returns the style context associated to @widget.
Fetch an object build from the template XML for @widget_type in this @widget instance.
Gets the contents of the tooltip for @widget.
Gets the contents of the tooltip for @widget.
Gets whether the widget would like any available extra vertical space.
Gets whether gtk_widget_set_vexpand() has been used to explicitly set the expand flag on this widget.
Determines whether the widget is visible.
Returns whether @css_class is currently applied to @widget.
Determines whether @widget is the current default widget within its toplevel.
Determines if the widget should show a visible indication that it has the global input focus.
Returns whether the widget is currently being destroyed.
Creates and initializes child widgets defined in templates.
Inserts @group into @widget.
Inserts @widget into the child widget list of @parent.
Inserts @widget into the child widget list of @parent.
Determines whether @widget is somewhere inside @ancestor, possibly with intermediate containers.
Determines whether @widget can be drawn to.
Returns the widget’s effective sensitivity.
Emits the ::keynav-failed signal on the widget.
Returns the widgets for which this widget is the target of a mnemonic.
Emits the ::mnemonic-activate signal.
Returns a GListModel to track the children of @widget.
Returns a GListModel to track the class@Gtk.EventControllers of @widget.
Flags the widget for a rerun of the vfunc@Gtk.Widget.size_allocate function.
Flags a widget to have its size renegotiated.
Removes @controller from @widget, so that it doesn't process events anymore.
Removes a style from @widget.
Removes a widget from the list of mnemonic labels for this widget.
Removes a tick callback previously registered with gtk_widget_add_tick_callback().
Resets the accessible @property to its default value.
Resets the accessible @relation to its default value.
Resets the accessible @state to its default value.
Sets the parent and sibling of an accessible object.
Specifies whether the input focus can enter the widget or any of its children.
Sets whether @widget can be the target of pointer events.
Sets whether @widget should be mapped along with its parent.
Sets the desired height of the contents of the drawing area.
Sets the desired width of the contents of the drawing area.
Clear all style classes applied to @widget and replace them with @classes.
Sets a named cursor to be shown when pointer devices point towards @widget.
Sets the reading direction on a particular widget.
Setting a draw function is the main thing you want to do when using a drawing area.
Specifies whether @widget can own the input focus.
Set @child as the current focus child of @widget.
Sets whether the widget should grab focus when it is clicked with the mouse.
Sets the font map to use for Pango rendering.
Sets the has-tooltip property on @widget to @has_tooltip.
Sets whether the widget would like any available extra horizontal space.
Sets whether the hexpand flag will be used.
Sets the layout manager delegate instance that provides an implementation for measuring and allocating the children of @widget.
Sets the bottom margin of @widget.
Sets the end margin of @widget.
Set all margins to the same value.
Set start and end margin to horizontal and top and bottom margin to vertical
Set margins.
Sets the start margin of @widget.
Sets the top margin of @widget.
Request the @widget to be rendered partially transparent.
Sets how @widget treats content that is drawn outside the widget's content area.
Specifies whether @widget will be treated as the default widget within its toplevel when it has the focus, even if another widget is the default.
Sets the sensitivity of a widget.
Sets the minimum size of a widget.
Turns on flag values in the current widget state.
Sets @markup as the contents of the tooltip, which is marked up with Pango markup.
Sets @text as the contents of the tooltip.
Sets whether the widget would like any available extra vertical space.
Sets whether the vexpand flag will be used.
Sets the visibility state of @widget.
Returns whether @widget should contribute to the measuring and allocation of its parent.
Triggers a tooltip query on the display where the toplevel of @widget is located.
Turns off flag values for the current widget state.
Updates the next accessible sibling of @self.