/* GTK - The GIMP Toolkit

 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#include <stdlib.h>

#include <gtk/gtk.h>

/* Backing pixmap for drawing area */

static GdkPixmap *pixmap = NULL;

/* Create a new backing pixmap of the appropriate size */

static gboolean configure_event( GtkWidget         *widget,

                                 GdkEventConfigure *event )

{

  if (pixmap)

    g_object_unref (pixmap);

  pixmap = gdk_pixmap_new (widget->window,

			   widget->allocation.width,

			   widget->allocation.height,

			   -1);

  gdk_draw_rectangle (pixmap,

		      widget->style->white_gc,

		      TRUE,

		      0, 0,

		      widget->allocation.width,

		      widget->allocation.height);

  return TRUE;

}

/* Redraw the screen from the backing pixmap */

static gboolean expose_event( GtkWidget      *widget,

                              GdkEventExpose *event )

{

  gdk_draw_drawable (widget->window,

		     widget->style->fg_gc[gtk_widget_get_state (widget)],

		     pixmap,

		     event->area.x, event->area.y,

		     event->area.x, event->area.y,

		     event->area.width, event->area.height);

  return FALSE;

}

/* Draw a rectangle on the screen */

static void draw_brush( GtkWidget *widget,

                        gdouble    x,

                        gdouble    y)

{

  GdkRectangle update_rect;

  update_rect.x = x - 5;

  update_rect.y = y - 5;

  update_rect.width = 10;

  update_rect.height = 10;

  gdk_draw_rectangle (pixmap,

		      widget->style->black_gc,

		      TRUE,

		      update_rect.x, update_rect.y,

		      update_rect.width, update_rect.height);

  gtk_widget_queue_draw_area (widget, 

		              update_rect.x, update_rect.y,

		              update_rect.width, update_rect.height);

}

static gboolean button_press_event( GtkWidget      *widget,

                                    GdkEventButton *event )

{

  if (event->button == 1 && pixmap != NULL)

    draw_brush (widget, event->x, event->y);

  return TRUE;

}

static gboolean motion_notify_event( GtkWidget *widget,

                                     GdkEventMotion *event )

{

  int x, y;

  GdkModifierType state;

  if (event->is_hint)

    gdk_window_get_pointer (event->window, &x, &y, &state);

  else

    {

      x = event->x;

      y = event->y;

      state = event->state;

    }

  if (state & GDK_BUTTON1_MASK && pixmap != NULL)

    draw_brush (widget, x, y);

  return TRUE;

}

void quit ()

{

  exit (0);

}

int main( int   argc, 

          char *argv[] )

{

  GtkWidget *window;

  GtkWidget *drawing_area;

  GtkWidget *vbox;

  GtkWidget *button;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

  gtk_widget_set_name (window, "Test Input");

  vbox = gtk_vbox_new (FALSE, 0);

  gtk_container_add (GTK_CONTAINER (window), vbox);

  gtk_widget_show (vbox);

  g_signal_connect (window, "destroy",

                    G_CALLBACK (quit), NULL);

  /* Create the drawing area */

  drawing_area = gtk_drawing_area_new ();

  gtk_widget_set_size_request (GTK_WIDGET (drawing_area), 200, 200);

  gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);

  gtk_widget_show (drawing_area);

  /* Signals used to handle backing pixmap */

  g_signal_connect (drawing_area, "expose-event",

		    G_CALLBACK (expose_event), NULL);

  g_signal_connect (drawing_area,"configure-event",

		    G_CALLBACK (configure_event), NULL);

  /* Event signals */

  g_signal_connect (drawing_area, "motion-notify-event",

		    G_CALLBACK (motion_notify_event), NULL);

  g_signal_connect (drawing_area, "button-press-event",

		    G_CALLBACK (button_press_event), NULL);

  gtk_widget_set_events (drawing_area, GDK_EXPOSURE_MASK

			 | GDK_LEAVE_NOTIFY_MASK

			 | GDK_BUTTON_PRESS_MASK

			 | GDK_POINTER_MOTION_MASK

			 | GDK_POINTER_MOTION_HINT_MASK);

  /* .. And a quit button */

  button = gtk_button_new_with_label ("Quit");

  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  g_signal_connect_swapped (button, "clicked",

			    G_CALLBACK (gtk_widget_destroy),

			    window);

  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;

}