GTK+ Reference Manual
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GtkDrawingArea

Name

GtkDrawingArea -- a widget for custom user interface elements.

Synopsis


#include <gtk/gtk.h>


struct      GtkDrawingArea;
GtkWidget*  gtk_drawing_area_new            (void);
void        gtk_drawing_area_size           (GtkDrawingArea *darea,
                                             gint width,
                                             gint height);

Object Hierarchy


  GtkObject
   +----GtkWidget
         +----GtkDrawingArea

Description

The GtkDrawingArea widget is used for creating custom user interface elements. After creating a drawing area, the application may want to connect to:

As a convenience, the GtkDrawingArea widget synthesizes a "configure_event" when the widget is realized and any time the size of a widget changes when it is realized. It often suffices to connect to this signal instead of "realize" and "size_allocate".

The following code portion demonstrates using a drawing area to implement a widget that draws a circle. As this example demonstrates, an expose handler should draw only the pixels within the requested area and should draw or clear all these pixels.

gboolean
expose_event (GdkWidget *widget, GdkEventExpose *event, gpointer data)
{
  gdk_window_clear_area (widget->window,
                         event->area.x, event->area.y,
                         event->area.width, event->area.height);
  gdk_gc_set_clip_rectangle (widget->style->fg_gc[widget->state],
                             &event->area);
  gdk_draw_arc (widget->window,
                widget->style->fg_gc[widget->state],
                TRUE,
                0, 0, widget->allocation.width, widget->allocation.height,
                0, 64 * 360);
  gdk_gc_set_clip_rectangle (widget->style->fg_gc[widget->state],
                             NULL);

  return TRUE;
}
[...]
  GtkWidget *drawing_area = gdk_drawing_area_new();
  gdk_drawing_area_size (GTK_DRAWING_AREA (drawing_area),
                         100, 100);
  gtk_signal_connect (GTK_OBJECT (drawing_area),

Details

struct GtkDrawingArea

struct GtkDrawingArea;

The GtkDrawingArea struct contains private data only, and should be accessed using the functions below.

gtk_drawing_area_new ()

GtkWidget*  gtk_drawing_area_new            (void);

Create a new drawing area.

Returns : 

gtk_drawing_area_size ()

void        gtk_drawing_area_size           (GtkDrawingArea *darea,
                                             gint width,
                                             gint height);

Set 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.



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