examples/scribble-simple/scribble-simple.c

   1
   2 /* GTK - The GIMP Toolkit
   3  * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Library General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Library General Public
  16  * License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <stdlib.h>
  22 #include <gtk/gtk.h>
  23
  24 /* Backing pixmap for drawing area */
  25 static GdkPixmap *pixmap = NULL;
  26
  27 /* Create a new backing pixmap of the appropriate size */
  28 static gboolean configure_event( GtkWidget         *widget,
  29                                  GdkEventConfigure *event )
  30 {
  31   if (pixmap)
  32     g_object_unref (pixmap);
  33
  34   pixmap = gdk_pixmap_new (widget->window,
  35                            widget->allocation.width,
  36                            widget->allocation.height,
  37                            -1);
  38   gdk_draw_rectangle (pixmap,
  39                       widget->style->white_gc,
  40                       TRUE,
  41                       0, 0,
  42                       widget->allocation.width,
  43                       widget->allocation.height);
  44
  45   return TRUE;
  46 }
  47
  48 /* Redraw the screen from the backing pixmap */
  49 static gboolean expose_event( GtkWidget      *widget,
  50                               GdkEventExpose *event )
  51 {
  52   gdk_draw_drawable (widget->window,
  53                      widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
  54                      pixmap,
  55                      event->area.x, event->area.y,
  56                      event->area.x, event->area.y,
  57                      event->area.width, event->area.height);
  58
  59   return FALSE;
  60 }
  61
  62 /* Draw a rectangle on the screen */
  63 static void draw_brush( GtkWidget *widget,
  64                         gdouble    x,
  65                         gdouble    y)
  66 {
  67   GdkRectangle update_rect;
  68
  69   update_rect.x = x - 5;
  70   update_rect.y = y - 5;
  71   update_rect.width = 10;
  72   update_rect.height = 10;
  73   gdk_draw_rectangle (pixmap,
  74                       widget->style->black_gc,
  75                       TRUE,
  76                       update_rect.x, update_rect.y,
  77                       update_rect.width, update_rect.height);
  78   gtk_widget_queue_draw_area (widget,
  79                               update_rect.x, update_rect.y,
  80                               update_rect.width, update_rect.height);
  81 }
  82
  83 static gboolean button_press_event( GtkWidget      *widget,
  84                                     GdkEventButton *event )
  85 {
  86   if (event->button == 1 && pixmap != NULL)
  87     draw_brush (widget, event->x, event->y);
  88
  89   return TRUE;
  90 }
  91
  92 static gboolean motion_notify_event( GtkWidget *widget,
  93                                      GdkEventMotion *event )
  94 {
  95   int x, y;
  96   GdkModifierType state;
  97
  98   if (event->is_hint)
  99     gdk_window_get_pointer (event->window, &x, &y, &state);
 100   else
 101     {
 102       x = event->x;
 103       y = event->y;
 104       state = event->state;
 105     }
 106
 107   if (state & GDK_BUTTON1_MASK && pixmap != NULL)
 108     draw_brush (widget, x, y);
 109
 110   return TRUE;
 111 }
 112
 113 void quit ()
 114 {
 115   exit (0);
 116 }
 117
 118 int main( int   argc,
 119           char *argv[] )
 120 {
 121   GtkWidget *window;
 122   GtkWidget *drawing_area;
 123   GtkWidget *vbox;
 124
 125   GtkWidget *button;
 126
 127   gtk_init (&argc, &argv);
 128
 129   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
 130   gtk_widget_set_name (window, "Test Input");
 131
 132   vbox = gtk_vbox_new (FALSE, 0);
 133   gtk_container_add (GTK_CONTAINER (window), vbox);
 134   gtk_widget_show (vbox);
 135
 136   g_signal_connect (G_OBJECT (window), "destroy",
 137                     G_CALLBACK (quit), NULL);
 138
 139   /* Create the drawing area */
 140
 141   drawing_area = gtk_drawing_area_new ();
 142   gtk_widget_set_size_request (GTK_WIDGET (drawing_area), 200, 200);
 143   gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);
 144
 145   gtk_widget_show (drawing_area);
 146
 147   /* Signals used to handle backing pixmap */
 148
 149   g_signal_connect (G_OBJECT (drawing_area), "expose_event",
 150                     G_CALLBACK (expose_event), NULL);
 151   g_signal_connect (G_OBJECT (drawing_area),"configure_event",
 152                     G_CALLBACK (configure_event), NULL);
 153
 154   /* Event signals */
 155
 156   g_signal_connect (G_OBJECT (drawing_area), "motion_notify_event",
 157                     G_CALLBACK (motion_notify_event), NULL);
 158   g_signal_connect (G_OBJECT (drawing_area), "button_press_event",
 159                     G_CALLBACK (button_press_event), NULL);
 160
 161   gtk_widget_set_events (drawing_area, GDK_EXPOSURE_MASK
 162                          | GDK_LEAVE_NOTIFY_MASK
 163                          | GDK_BUTTON_PRESS_MASK
 164                          | GDK_POINTER_MOTION_MASK
 165                          | GDK_POINTER_MOTION_HINT_MASK);
 166
 167   /* .. And a quit button */
 168   button = gtk_button_new_with_label ("Quit");
 169   gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
 170
 171   g_signal_connect_swapped (G_OBJECT (button), "clicked",
 172                             G_CALLBACK (gtk_widget_destroy),
 173                             G_OBJECT (window));
 174   gtk_widget_show (button);
 175
 176   gtk_widget_show (window);
 177
 178   gtk_main ();
 179
 180   return 0;
 181 }