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/* GdkPixbuf library - Scaling and compositing demo
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* Copyright (C) 1999 The Free Software Foundation
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* Authors: Federico Mena-Quintero <federico@gimp.org>
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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#include <gdk-pixbuf/gdk-pixbuf.h>
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#define FRAME_DELAY 50
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#define BACKGROUND_NAME "background.jpg"
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static const char *image_names[] = {
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#define N_IMAGES (sizeof (image_names) / sizeof (image_names[0]))
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static GdkPixbuf *frame;
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/* Background image */
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static GdkPixbuf *background;
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int back_width, back_height;
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static GdkPixbuf *images[N_IMAGES];
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/* Loads the images for the demo and returns whether the operation succeeded */
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background = gdk_pixbuf_new_from_file (BACKGROUND_NAME);
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back_width = gdk_pixbuf_get_width (background);
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back_height = gdk_pixbuf_get_height (background);
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for (i = 0; i < N_IMAGES; i++) {
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images[i] = gdk_pixbuf_new_from_file (image_names[i]);
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/* Expose callback for the drawing area */
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expose_cb (GtkWidget *widget, GdkEventExpose *event, gpointer data)
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rowstride = gdk_pixbuf_get_rowstride (frame);
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pixels = gdk_pixbuf_get_pixels (frame) + rowstride * event->area.y + event->area.x * 3;
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gdk_draw_rgb_image_dithalign (widget->window,
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widget->style->black_gc,
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event->area.x, event->area.y,
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event->area.width, event->area.height,
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GDK_RGB_DITHER_NORMAL,
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event->area.x, event->area.y);
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static int frame_num;
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/* Timeout handler to regenerate the frame */
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timeout (gpointer data)
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gdk_pixbuf_copy_area (background, 0, 0, back_width, back_height,
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f = (double) (frame_num % CYCLE_LEN) / CYCLE_LEN;
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xmid = back_width / 2.0;
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ymid = back_height / 2.0;
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radius = MIN (xmid, ymid) / 2.0;
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for (i = 0; i < N_IMAGES; i++) {
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GdkRectangle r1, r2, dest;
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ang = 2.0 * M_PI * (double) i / N_IMAGES - f * 2.0 * M_PI;
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iw = gdk_pixbuf_get_width (images[i]);
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ih = gdk_pixbuf_get_height (images[i]);
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r = radius + (radius / 3.0) * sin (f * 2.0 * M_PI);
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xpos = floor (xmid + r * cos (ang) - iw / 2.0 + 0.5);
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ypos = floor (ymid + r * sin (ang) - ih / 2.0 + 0.5);
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k = (i & 1) ? sin (f * 2.0 * M_PI) : cos (f * 2.0 * M_PI);
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r2.width = back_width;
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r2.height = back_height;
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if (gdk_rectangle_intersect (&r1, &r2, &dest))
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gdk_pixbuf_composite (images[i],
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dest.width, dest.height,
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? MAX (127, fabs (255 * sin (f * 2.0 * M_PI)))
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: MAX (127, fabs (255 * cos (f * 2.0 * M_PI)))));
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gtk_widget_draw (da, NULL);
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static guint timeout_id;
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/* Destroy handler for the window */
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destroy_cb (GtkObject *object, gpointer data)
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gtk_timeout_remove (timeout_id);
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main (int argc, char **argv)
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gtk_init (&argc, &argv);
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if (!load_pixbufs ()) {
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g_message ("main(): Could not load all the pixbufs!");
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frame = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, back_width, back_height);
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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gtk_widget_set_usize (window, back_width, back_height);
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gtk_window_set_policy (GTK_WINDOW (window), FALSE, FALSE, FALSE);
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gtk_signal_connect (GTK_OBJECT (window), "destroy",
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GTK_SIGNAL_FUNC (destroy_cb), NULL);
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gtk_widget_push_visual (gdk_rgb_get_visual ());
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gtk_widget_push_colormap (gdk_rgb_get_cmap ());
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da = gtk_drawing_area_new ();
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gtk_widget_pop_visual ();
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gtk_widget_pop_colormap ();
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gtk_signal_connect (GTK_OBJECT (da), "expose_event",
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GTK_SIGNAL_FUNC (expose_cb), NULL);
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gtk_container_add (GTK_CONTAINER (window), da);
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timeout_id = gtk_timeout_add (FRAME_DELAY, timeout, NULL);
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gtk_widget_show_all (window);