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GtkDrawingArea — a widget for custom user interface elements.
#include <gtk/gtk.h> struct GtkDrawingArea; GtkWidget* gtk_drawing_area_new (void); void gtk_drawing_area_size (GtkDrawingArea *darea,gint width,gint height);
GtkDrawingArea implements
Mouse and button press signals to respond to input from the user. (Use gtk_widget_add_events() to enable events you wish to receive.)
The "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 "configure_event" signal to take any necessary actions when the widget changes size.
The "expose_event" signal 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. Note that GDK automatically clears the exposed area to the background color before sending the expose event, and that drawing is implicitly clipped to the exposed area.
Example 1. Simple GtkDrawingArea usage.
gboolean expose_event_callback (GtkWidget *widget, GdkEventExpose *event, gpointer data) { gdk_draw_arc (widget->window, widget->style->fg_gc[GTK_WIDGET_STATE (widget)], TRUE, 0, 0, widget->allocation.width, widget->allocation.height, 0, 64 * 360); return TRUE; } [...] GtkWidget *drawing_area = gtk_drawing_area_new (); gtk_widget_set_size_request (drawing_area, 100, 100); g_signal_connect (G_OBJECT (drawing_area), "expose_event", G_CALLBACK (expose_event_callback), NULL);
Expose events are normally delivered when a drawing area first comes
onscreen, or when it's covered by another window and then uncovered
(exposed). You can also force an expose event by adding to the "damage
region" of the drawing area's window; gtk_widget_queue_draw_area() and
The available routines for drawing are documented on the
To receive mouse events on a drawing area, you will need to enable
them with gtk_widget_add_events(). To receive keyboard events, you
will need to set the
struct GtkDrawingArea;
The GtkDrawingArea struct contains private data only, and should be accessed using the functions below.
GtkWidget* gtk_drawing_area_new (void);
Creates a new drawing area.
Returns : | a new GtkDrawingArea |
void gtk_drawing_area_size (GtkDrawingArea *darea,gint width,gint height);
gtk_drawing_area_size is deprecated and should not be used in newly-written code.
(Use gtk_widget_set_size_request() instead.) Sets the size that the drawing area will request in response to a "size_request" signal. The drawing area may actually be allocated a size larger than this depending on how it is packed within the enclosing containers.
darea : | a GtkDrawingArea. |
width : | the width to request. |
height : | the height to request. |
Sometimes GtkImage is a useful alternative to a drawing area.
You can put a
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