sec-scribble.html

gtk的教材和问答集

  gtk_signal_connect (GTK_OBJECT (drawing_area), "button_press_event",
		      (GtkSignalFunc) 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);

  gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
			     GTK_SIGNAL_FUNC (gtk_widget_destroy),
			     GTK_OBJECT (window));
  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
}
/* example-end */</PRE
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>C.3.2. scribble-xinput.c</A
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CLASS="PROGRAMLISTING"
>/* example-start scribble-xinput scribble-xinput.c */

/* 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 &#60;gtk/gtk.h&#62;

/* Backing pixmap for drawing area */
static GdkPixmap *pixmap = NULL;

/* Create a new backing pixmap of the appropriate size */
static gint
configure_event (GtkWidget *widget, GdkEventConfigure *event)
{
  if (pixmap)
     gdk_pixmap_unref(pixmap);

  pixmap = gdk_pixmap_new(widget-&#62;window,
                          widget-&#62;allocation.width,
                          widget-&#62;allocation.height,
                          -1);
  gdk_draw_rectangle (pixmap,
                      widget-&#62;style-&#62;white_gc,
                      TRUE,
                      0, 0,
                      widget-&#62;allocation.width,
                      widget-&#62;allocation.height);

  return TRUE;
}

/* Redraw the screen from the backing pixmap */
static gint
expose_event (GtkWidget *widget, GdkEventExpose *event)
{
  gdk_draw_pixmap(widget-&#62;window,
                  widget-&#62;style-&#62;fg_gc[GTK_WIDGET_STATE (widget)],
                  pixmap,
                  event-&#62;area.x, event-&#62;area.y,
                  event-&#62;area.x, event-&#62;area.y,
                  event-&#62;area.width, event-&#62;area.height);

  return FALSE;
}

/* Draw a rectangle on the screen, size depending on pressure,
   and color on the type of device */
static void
draw_brush (GtkWidget *widget, GdkInputSource source,
            gdouble x, gdouble y, gdouble pressure)
{
  GdkGC *gc;
  GdkRectangle update_rect;

  switch (source)
    {
    case GDK_SOURCE_MOUSE:
      gc = widget-&#62;style-&#62;dark_gc[GTK_WIDGET_STATE (widget)];
      break;
    case GDK_SOURCE_PEN:
      gc = widget-&#62;style-&#62;black_gc;
      break;
    case GDK_SOURCE_ERASER:
      gc = widget-&#62;style-&#62;white_gc;
      break;
    default:
      gc = widget-&#62;style-&#62;light_gc[GTK_WIDGET_STATE (widget)];
    }

  update_rect.x = x - 10 * pressure;
  update_rect.y = y - 10 * pressure;
  update_rect.width = 20 * pressure;
  update_rect.height = 20 * pressure;
  gdk_draw_rectangle (pixmap, gc, TRUE,
                      update_rect.x, update_rect.y,
                      update_rect.width, update_rect.height);
  gtk_widget_draw (widget, &#38;update_rect);
}

static void
print_button_press (guint32 deviceid)
{
  GList *tmp_list;

  /* gdk_input_list_devices returns an internal list, so we shouldn't
     free it afterwards */
  tmp_list = gdk_input_list_devices();

  while (tmp_list)
    {
      GdkDeviceInfo *info = (GdkDeviceInfo *)tmp_list-&#62;data;

      if (info-&#62;deviceid == deviceid)
        {
          g_print("Button press on device '%s'\n", info-&#62;name);
          return;
        }

      tmp_list = tmp_list-&#62;next;
    }
}

static gint
button_press_event (GtkWidget *widget, GdkEventButton *event)
{
  print_button_press (event-&#62;deviceid);
  
  if (event-&#62;button == 1 &#38;&#38; pixmap != NULL)
    draw_brush (widget, event-&#62;source, event-&#62;x, event-&#62;y, event-&#62;pressure);

  return TRUE;
}

static gint
motion_notify_event (GtkWidget *widget, GdkEventMotion *event)
{
  gdouble x, y;
  gdouble pressure;
  GdkModifierType state;

  if (event-&#62;is_hint)
    gdk_input_window_get_pointer (event-&#62;window, event-&#62;deviceid,
                                  &#38;x, &#38;y, &#38;pressure,
				  NULL, NULL, &#38;state);
  else
    {
      x = event-&#62;x;
      y = event-&#62;y;
      pressure = event-&#62;pressure;
      state = event-&#62;state;
    }
    
  if (state &#38; GDK_BUTTON1_MASK &#38;&#38; pixmap != NULL)
    draw_brush (widget, event-&#62;source, x, y, pressure);
  
  return TRUE;
}

void
input_dialog_destroy (GtkWidget *w, gpointer data)
{
  *((GtkWidget **)data) = NULL;
}

void
create_input_dialog ()
{
  static GtkWidget *inputd = NULL;

  if (!inputd)
    {
      inputd = gtk_input_dialog_new();

      gtk_signal_connect (GTK_OBJECT(inputd), "destroy",
                          (GtkSignalFunc)input_dialog_destroy, &#38;inputd);
      gtk_signal_connect_object (GTK_OBJECT(GTK_INPUT_DIALOG(inputd)-&#62;close_button),
                                 "clicked",
                                 (GtkSignalFunc)gtk_widget_hide,
                                 GTK_OBJECT(inputd));
      gtk_widget_hide ( GTK_INPUT_DIALOG(inputd)-&#62;save_button);

      gtk_widget_show (inputd);
    }
  else
    {
      if (!GTK_WIDGET_MAPPED(inputd))
        gtk_widget_show(inputd);
      else
        gdk_window_raise(inputd-&#62;window);
    }
}

void
quit ()
{
  gtk_exit (0);
}

int
main (int argc, char *argv[])
{
  GtkWidget *window;
  GtkWidget *drawing_area;
  GtkWidget *vbox;

  GtkWidget *button;

  gtk_init (&#38;argc, &#38;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);

  gtk_signal_connect (GTK_OBJECT (window), "destroy",
                      GTK_SIGNAL_FUNC (quit), NULL);

  /* Create the drawing area */

  drawing_area = gtk_drawing_area_new ();
  gtk_drawing_area_size (GTK_DRAWING_AREA (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 */

  gtk_signal_connect (GTK_OBJECT (drawing_area), "expose_event",
                      (GtkSignalFunc) expose_event, NULL);
  gtk_signal_connect (GTK_OBJECT(drawing_area),"configure_event",
                      (GtkSignalFunc) configure_event, NULL);

  /* Event signals */

  gtk_signal_connect (GTK_OBJECT (drawing_area), "motion_notify_event",
                      (GtkSignalFunc) motion_notify_event, NULL);
  gtk_signal_connect (GTK_OBJECT (drawing_area), "button_press_event",
                      (GtkSignalFunc) 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);

  /* The following call enables tracking and processing of extension
     events for the drawing area */
  gtk_widget_set_extension_events (drawing_area, GDK_EXTENSION_EVENTS_CURSOR);

  /* .. And some buttons */
  button = gtk_button_new_with_label ("Input Dialog");
  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  gtk_signal_connect (GTK_OBJECT (button), "clicked",
                      GTK_SIGNAL_FUNC (create_input_dialog), NULL);
  gtk_widget_show (button);

  button = gtk_button_new_with_label ("Quit");
  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
                             GTK_SIGNAL_FUNC (gtk_widget_destroy),
                             GTK_OBJECT (window));
  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
}
/* example-end */</PRE
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