There are a few types you've probably noticed in the previous
examples that might need explaining. The gint, gchar and
other "2void
gtk_dial_adjustment_value_changed (GtkAdjustment *adjustment,
gpointer data)
{
GtkDial *dial;
g_return_if_fail (adjustment != NULL);
g_return_if_fail (data != NULL);
dial = GTK_DIAL (data);
if (dial->old_value != adjustment->value)
{
gtk_dial_update (dial);
dial->old_value = adjustment->value;
}
}
/* example-end */
Source location: examples/scribble-simple/scribble-simple.cc
/* 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.
*
* Revision history:
* Modified for gtk-- by sac@transmeta.com
* Modified for gdk-- by freyd@uni-muenster.de
* Modified (Added Erase function) by k.i.beaumont@larc.nasa.gov
* General cleanup by Karl Nelson.
*/
#include <gtk--/main.h>
#include <gtk--/style.h>
#include <gtk--/window.h>
#include <gtk--/button.h>
#include <gtk--/box.h>
#include <gtk--/drawingarea.h>
class ScribbleDrawingArea : public Gtk::DrawingArea
{
/* Backing pixmap for drawing area */
Gdk_Pixmap pixmap;
Gdk_GC gc;
Gdk_GC brush_gc;
Gdk_Window win;
Gdk_Visual visual;
virtual gint configure_event_impl (GdkEventConfigure *event);
virtual gint expose_event_impl (GdkEventExpose *event);
virtual gint button_press_event_impl (GdkEventButton *event);
virtual gint motion_notify_event_impl (GdkEventMotion *event);
void draw_brush (gdouble x, gdouble y);
public:
void erase();
ScribbleDrawingArea ();
~ScribbleDrawingArea ();
};
ScribbleDrawingArea::ScribbleDrawingArea()
: Gtk::DrawingArea(), pixmap (0)
{
set_events (GDK_EXPOSURE_MASK
| GDK_LEAVE_NOTIFY_MASK
| GDK_BUTTON_PRESS_MASK
| GDK_POINTER_MOTION_MASK
| GDK_POINTER_MOTION_HINT_MASK);
}
ScribbleDrawingArea::~ScribbleDrawingArea()
{}
/* Create a new backing pixmap of the appropriate size */
int ScribbleDrawingArea::configure_event_impl (GdkEventConfigure * /* event */)
{
win = get_window();
visual = win.get_visual();
if (pixmap)
pixmap.release();
gc = get_style()->get_white_gc();
pixmap.create(get_window(), width(), height());
pixmap.draw_rectangle (gc, true, 0, 0, width(), height());
return true;
}
/* Redraw the screen from the backing pixmap */
int ScribbleDrawingArea::expose_event_impl (GdkEventExpose *event)
{
gc = get_style()->get_fg_gc(get_state());
win.draw_pixmap(gc ,
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 */
void ScribbleDrawingArea::draw_brush (gdouble x, gdouble y)
{
GdkRectangle update_rect;
update_rect.x = (int)x - 5;
update_rect.y = (int)y - 5;
update_rect.width = 10;
update_rect.height = 10;
// we can't create the brush gc in the ctor because there was not window
// so we will initialize it here once, and use it from then on.
if (!brush_gc)
{
brush_gc = Gdk_GC(pixmap);
Gdk_Color red("red");
get_colormap().alloc(red);
brush_gc.set_foreground(red);
}
pixmap.draw_rectangle(
brush_gc,
true,
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
draw(&update_rect);
}
gint ScribbleDrawingArea::button_press_event_impl (GdkEventButton *event)
{
if (event->button == 1 && pixmap)
draw_brush (event->x, event->y);
return true;
}
gint ScribbleDrawingArea::motion_notify_event_impl (GdkEventMotion *event)
{
int x, y;
GdkModifierType state;
Gdk_Window window(event->window);
if (event->is_hint)
window.get_pointer (x, y, state);
else
{
x = (int)event->x;
y = (int)event->y;
state = (GdkModifierType) event->state;
}
if (state & GDK_BUTTON1_MASK && pixmap)
draw_brush (x, y);
return true;
}
void ScribbleDrawingArea::erase()
{
// clear pixmap area to white.
gc = get_style()->get_white_gc();
pixmap.draw_rectangle (gc, true, 0, 0, width(), height());
// request a refresh of whole area.
draw(0);
}
/*****************************************************************/
class ScribbleWindow : public Gtk::Window
{
ScribbleDrawingArea drawing_area;
Gtk::Button eraser;
Gtk::Button button;
Gtk::VBox vbox;
public:
ScribbleWindow ();
~ScribbleWindow ();
};
ScribbleWindow::ScribbleWindow ()
: Gtk::Window(GTK_WINDOW_TOPLEVEL),
eraser("erase"),
button ("quit"),
vbox (false, 0)
{
add (vbox);
/* Create the drawing area */
drawing_area.size (400, 400);
vbox.pack_start (drawing_area, true, true, 0);
/* Add the buttons */
vbox.pack_start (eraser, false, false, 0);
vbox.pack_start (button, false, false, 0);
eraser.clicked.connect(slot(drawing_area, &ScribbleDrawingArea::erase));
button.clicked.connect(destroy.slot());
destroy.connect(Gtk::Main::quit.slot());
drawing_area.show();
eraser.show();
button.show();
vbox.show();
}
ScribbleWindow::~ScribbleWindow()
{}
int
main (int argc, char *argv[])
{
Gtk::Main myapp(argc, argv);
ScribbleWindow window;
window.show();
myapp.run();
return 0;
}