cairo-5c 1.10 / usr / share / doc / cairo-5c / spinman.5c

/* $Id$
 *
 * Copyright © 2004 Keith Packard
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Keith Packard
 *
 * Contributor(s):
 *      Keith Packard <keithp@keithp.com>
 */

autoimport Cairo;

const real off_x = -100;
const real off_y = 30;

void clear (cairo_t cr) {
    save (cr);
    identity_matrix (cr);
    set_source_rgb (cr, 1, 1, 1);
    rectangle (cr, 0, 0, width(cr), height(cr));
    fill (cr);
    restore (cr);
}

void picture (cairo_t cr)
{
    save (cr);
    
    set_source_rgb (cr, 0, 0, 0);
    move_to (cr, off_x, off_y);
#    show_text (cr, "nickle and cairo together");
    show_text (cr, "CAIRO");
    
    move_to (cr, off_x, off_y);
    rel_line_to (cr, 250, 0);
    set_source_rgb (cr, 0, 0, 1);
    stroke (cr);
    
    move_to (cr, 5, 0);
    arc (cr, 5, 0, 5, 0, 10);
    set_source_rgb (cr, 1, 0, 0);
    fill (cr);
    restore (cr);
}

typedef union {
    struct {
	int time;
	real x, y;
	int button;
    } press;
    struct {
	int time;
	real x, y;
    } motion;
    struct {
	int time;
	real x, y;
	int button;
    } release;
} event_t;

event_t
read_event (file f, cairo_t cr)
{
    for (;;) {
    event_t	e;
    string	line = File::fgets (f);
    file	l = File::string_read (line);
    File::fscanf (l, "%d %s", &(int time), &(string name));
    
    void transform_inplace (&real x, &real y)
    {
	point_t a = device_to_user (cr, (point_t) { x = x, y = y });
	x = a.x;
	y = a.y;
    }

    switch (name) {
    case "press":
	File::fscanf (l, "%d %d %d", &(int button), &(real x), &(real y));
        transform_inplace (&x, &y);
	return (event_t) { press = {
	    time = time, x = x, y = y, button = button
	}};
    case "release":
	File::fscanf (l, "%d %d %d", &(int button), &(real x), &(real y));
        transform_inplace (&x, &y);
	return (event_t) { release = {
	    time = time, x = x, y = y, button = button
	}};
    case "motion":
	File::fscanf (l, "%d %d", &(real x), &(real y));
        transform_inplace (&x, &y);
	return (event_t) { motion = {
	    time = time, x = x, y = y
	}};
    case "delete":
	exit (0);
    }
    }
}

void animate (cairo_t cr)
{
    translate (cr, 150, 150);
    real t = 0;
    bool down = false;
    file ef = open_event (cr);
    for (;;)
    {
	event_t ev = read_event (ef, cr);
	real x, y;
	union switch (ev) {
	case press p:
	    down = true;
	    x = p.x; y = p.y;
	    break;
	case motion m:
	    x = m.x; y = m.y;
	    break;
	case release:
	    down = false;
	    break;
	}
	if (down)
	{
	    t = atan2 (y, x);
	    disable (cr);
	    save (cr);
	    clear (cr);
	    save (cr);
	    set_font (cr, "sans-12");
	    set_source_rgb (cr, 0, 0, 0);
	    move_to (cr, 3, 20);
	    show_text (cr, sprintf ("%5.2f", t));
	    restore (cr);
	    rotate (cr, t);
	    picture (cr);
	    restore (cr);
	    enable (cr);
	}
    }
}

void main ()
{
    cairo_t cr = new ();
    
    set_font (cr, "bitstream vera sans-100");
    animate (cr);
}

if (dim(argv) > 0) main ();