/* GdkPixbuf library - Scaling and compositing demo

 *

 * Copyright (C) 1999 The Free Software Foundation

 *

 * Authors: Federico Mena-Quintero <federico@gimp.org>

 *

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

 * modify it under the terms of the GNU Lesser 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser 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 "config.h"

#include <stdlib.h>

#include <gtk/gtk.h>

#include <math.h>

#define FRAME_DELAY 50

#define BACKGROUND_NAME "background.jpg"

static const char *image_names[] = {

	"apple-red.png",

	"gnome-applets.png",

	"gnome-calendar.png",

	"gnome-foot.png",

	"gnome-gmush.png",

	"gnome-gimp.png",

	"gnome-gsame.png",

	"gnu-keys.png"

};

#define N_IMAGES (sizeof (image_names) / sizeof (image_names[0]))

/* Current frame */

static GdkPixbuf *frame;

/* Background image */

static GdkPixbuf *background;

static int back_width, back_height;

/* Images */

static GdkPixbuf *images[N_IMAGES];

/* Widgets */

static GtkWidget *da;

/* Loads the images for the demo and returns whether the operation succeeded */

static gboolean

load_pixbufs (void)

{

	int i;

        /* We pass NULL for the error return location, we don't care

         * about the error message.

         */

	background = gdk_pixbuf_new_from_file (BACKGROUND_NAME, NULL);

	if (!background)

		return FALSE;

	back_width = gdk_pixbuf_get_width (background);

	back_height = gdk_pixbuf_get_height (background);

	for (i = 0; i < N_IMAGES; i++) {

		images[i] = gdk_pixbuf_new_from_file (image_names[i], NULL);

		if (!images[i])

			return FALSE;

	}

	return TRUE;

}

/* Expose callback for the drawing area */

static gint

expose_cb (GtkWidget *widget, GdkEventExpose *event, gpointer data)

{

        cairo_t *cr;

        cr = gdk_cairo_create (event->window);

        gdk_cairo_set_source_pixbuf (cr, frame, 0, 0);

        gdk_cairo_rectangle (cr, &event->area);

        cairo_fill (cr);

        cairo_destroy (cr);

	return TRUE;

}

#define CYCLE_LEN 60

static int frame_num;

/* Timeout handler to regenerate the frame */

static gint

timeout (gpointer data)

{

	double f;

	int i;

	double xmid, ymid;

	double radius;

	gdk_pixbuf_copy_area (background, 0, 0, back_width, back_height,

			      frame, 0, 0);

	f = (double) (frame_num % CYCLE_LEN) / CYCLE_LEN;

	xmid = back_width / 2.0;

	ymid = back_height / 2.0;

	radius = MIN (xmid, ymid) / 2.0;

	for (i = 0; i < N_IMAGES; i++) {

		double ang;

		int xpos, ypos;

		int iw, ih;

		double r;

		GdkRectangle r1, r2, dest;

		double k;

		ang = 2.0 * G_PI * (double) i / N_IMAGES - f * 2.0 * G_PI;

		iw = gdk_pixbuf_get_width (images[i]);

		ih = gdk_pixbuf_get_height (images[i]);

		r = radius + (radius / 3.0) * sin (f * 2.0 * G_PI);

		xpos = floor (xmid + r * cos (ang) - iw / 2.0 + 0.5);

		ypos = floor (ymid + r * sin (ang) - ih / 2.0 + 0.5);

		k = (i & 1) ? sin (f * 2.0 * G_PI) : cos (f * 2.0 * G_PI);

		k = 2.0 * k * k;

		k = MAX (0.25, k);

		r1.x = xpos;

		r1.y = ypos;

		r1.width = iw * k;

		r1.height = ih * k;

		r2.x = 0;

		r2.y = 0;

		r2.width = back_width;

		r2.height = back_height;

		if (gdk_rectangle_intersect (&r1, &r2, &dest))

			gdk_pixbuf_composite (images[i],

					      frame,

					      dest.x, dest.y,

					      dest.width, dest.height,

					      xpos, ypos,

					      k, k,

					      GDK_INTERP_NEAREST,

					      ((i & 1)

					       ? MAX (127, fabs (255 * sin (f * 2.0 * G_PI)))

					       : MAX (127, fabs (255 * cos (f * 2.0 * G_PI)))));

	}

	gtk_widget_queue_draw (da);

	frame_num++;

	return TRUE;

}

static guint timeout_id;

/* Destroy handler for the window */

static void

destroy_cb (GtkObject *object, gpointer data)

{

	g_source_remove (timeout_id);

	timeout_id = 0;

	gtk_main_quit ();

}

extern void pixbuf_init();

int

main (int argc, char **argv)

{

	GtkWidget *window;

	pixbuf_init ();

	gtk_init (&argc, &argv);

	if (!load_pixbufs ()) {

		g_message ("main(): Could not load all the pixbufs!");

		exit (EXIT_FAILURE);

	}

	frame = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, back_width, back_height);

	window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

	gtk_widget_set_size_request (window, back_width, back_height);

        gtk_window_set_resizable (GTK_WINDOW (window), FALSE);

	g_signal_connect (window, "destroy",

			  G_CALLBACK (destroy_cb), NULL);

	da = gtk_drawing_area_new ();

	g_signal_connect (da, "expose_event",

			  G_CALLBACK (expose_cb), NULL);

	gtk_container_add (GTK_CONTAINER (window), da);

	timeout_id = gdk_threads_add_timeout (FRAME_DELAY, timeout, NULL);

	gtk_widget_show_all (window);

	gtk_main ();

	return 0;

}