3 * A GdkPixbuf represents an image, normally in RGB or RGBA format.
4 * Pixbufs are normally used to load files from disk and perform
7 * This demo is not all that educational, but looks cool. It was written
8 * by Extreme Pixbuf Hacker Federico Mena Quintero. It also shows
9 * off how to use GtkDrawingArea to do a simple animation.
11 * Look at the Image demo for additional pixbuf usage examples.
20 #define FRAME_DELAY 50
22 #define RELATIVE_BACKGROUND_NAME "background.jpg"
23 #define INSTALLED_BACKGROUND_NAME DEMOCODEDIR"/background.jpg"
25 static const char *relative_image_names[] = {
36 static const char *installed_image_names[] = {
37 DEMOCODEDIR"/apple-red.png",
38 DEMOCODEDIR"/gnome-applets.png",
39 DEMOCODEDIR"/gnome-calendar.png",
40 DEMOCODEDIR"/gnome-foot.png",
41 DEMOCODEDIR"/gnome-gmush.png",
42 DEMOCODEDIR"/gnome-gimp.png",
43 DEMOCODEDIR"/gnome-gsame.png",
44 DEMOCODEDIR"/gnu-keys.png"
47 #define N_IMAGES G_N_ELEMENTS (relative_image_names)
50 static GtkWidget *window = NULL;
53 static GdkPixbuf *frame;
55 /* Background image */
56 static GdkPixbuf *background;
57 static gint back_width, back_height;
60 static GdkPixbuf *images[N_IMAGES];
65 /* Loads the images for the demo and returns whether the operation succeeded */
67 load_pixbufs (GError **error)
70 const gchar **image_names;
73 return TRUE; /* already loaded earlier */
75 background = gdk_pixbuf_new_from_file (RELATIVE_BACKGROUND_NAME, NULL);
78 background = gdk_pixbuf_new_from_file (INSTALLED_BACKGROUND_NAME, error);
81 return FALSE; /* note that "error" was filled in and returned */
83 back_width = gdk_pixbuf_get_width (background);
84 back_height = gdk_pixbuf_get_height (background);
86 if (g_file_test (relative_image_names[0], G_FILE_TEST_EXISTS))
87 image_names = relative_image_names;
89 image_names = installed_image_names;
91 for (i = 0; i < N_IMAGES; i++)
93 images[i] = gdk_pixbuf_new_from_file (image_names[i], error);
95 return FALSE; /* Note that "error" was filled with a GError */
101 /* Expose callback for the drawing area */
103 expose_cb (GtkWidget *widget,
104 GdkEventExpose *event,
110 rowstride = gdk_pixbuf_get_rowstride (frame);
112 pixels = gdk_pixbuf_get_pixels (frame) + rowstride * event->area.y + event->area.x * 3;
114 gdk_draw_rgb_image_dithalign (widget->window,
115 widget->style->black_gc,
116 event->area.x, event->area.y,
117 event->area.width, event->area.height,
118 GDK_RGB_DITHER_NORMAL,
120 event->area.x, event->area.y);
127 static int frame_num;
129 /* Timeout handler to regenerate the frame */
131 timeout (gpointer data)
138 gdk_pixbuf_copy_area (background, 0, 0, back_width, back_height,
141 f = (double) (frame_num % CYCLE_LEN) / CYCLE_LEN;
143 xmid = back_width / 2.0;
144 ymid = back_height / 2.0;
146 radius = MIN (xmid, ymid) / 2.0;
148 for (i = 0; i < N_IMAGES; i++)
154 GdkRectangle r1, r2, dest;
157 ang = 2.0 * M_PI * (double) i / N_IMAGES - f * 2.0 * M_PI;
159 iw = gdk_pixbuf_get_width (images[i]);
160 ih = gdk_pixbuf_get_height (images[i]);
162 r = radius + (radius / 3.0) * sin (f * 2.0 * M_PI);
164 xpos = floor (xmid + r * cos (ang) - iw / 2.0 + 0.5);
165 ypos = floor (ymid + r * sin (ang) - ih / 2.0 + 0.5);
167 k = (i & 1) ? sin (f * 2.0 * M_PI) : cos (f * 2.0 * M_PI);
178 r2.width = back_width;
179 r2.height = back_height;
181 if (gdk_rectangle_intersect (&r1, &r2, &dest))
182 gdk_pixbuf_composite (images[i],
185 dest.width, dest.height,
190 ? MAX (127, fabs (255 * sin (f * 2.0 * M_PI)))
191 : MAX (127, fabs (255 * cos (f * 2.0 * M_PI)))));
194 gtk_widget_queue_draw (da);
200 static guint timeout_id;
203 cleanup_callback (GtkObject *object,
206 g_source_remove (timeout_id);
218 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
219 gtk_window_set_title (GTK_WINDOW (window), "Pixbufs");
220 gtk_window_set_resizable (GTK_WINDOW (window), FALSE);
222 gtk_signal_connect (GTK_OBJECT (window), "destroy", GTK_SIGNAL_FUNC (gtk_widget_destroyed), &window);
223 gtk_signal_connect (GTK_OBJECT (window), "destroy", GTK_SIGNAL_FUNC (cleanup_callback), NULL);
227 if (!load_pixbufs (&error))
231 dialog = gtk_message_dialog_new (GTK_WINDOW (window),
232 GTK_DIALOG_DESTROY_WITH_PARENT,
235 "Failed to load an image: %s",
238 g_error_free (error);
240 gtk_signal_connect (GTK_OBJECT (dialog),
242 GTK_SIGNAL_FUNC (gtk_widget_destroy),
245 gtk_widget_show (dialog);
249 gtk_widget_set_size_request (window, back_width, back_height);
251 frame = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, back_width, back_height);
253 da = gtk_drawing_area_new ();
255 gtk_signal_connect (GTK_OBJECT (da), "expose_event",
256 GTK_SIGNAL_FUNC (expose_cb), NULL);
258 gtk_container_add (GTK_CONTAINER (window), da);
260 timeout_id = gtk_timeout_add (FRAME_DELAY, timeout, NULL);
264 if (!GTK_WIDGET_VISIBLE (window))
266 gtk_widget_show_all (window);
270 gtk_widget_destroy (window);