ftp://ftp.sunet.se/pub/os/Linux/distributions/ultrapenguin/ultrapenguin-1.1/SRPMS...

[xscreensaver] / utils / erase.c

diff --git a/utils/erase.c b/utils/erase.c
new file mode 100644 (file)
index 0000000..f30f971
--- /dev/null
+++ b/utils/erase.c
@@ -0,0 +1,128 @@
+/* erase.c: Erase the screen in various more or less interesting ways.
+ * (c) 1997 by Johannes Keukelaar <johannes@nada.kth.se>
+ * Permission to use in any way granted. Provided "as is" without expressed
+ * or implied warranty. NO WARRANTY, NO EXPRESSION OF SUITABILITY FOR ANY
+ * PURPOSE. (I.e.: Use in any way, but at your own risk!)
+ */
+
+#include "utils.h"
+#include "yarandom.h"
+#include "usleep.h"
+
+#define NUM_MODES 6
+
+void
+erase_window(Display *dpy, Window window, GC gc,
+            int width, int height, int mode, int delay)
+{
+  int *clear_lines;
+  int i, j, line, num_lines=0, granularity, max_num;
+
+  max_num = 2*height;
+  if(2*width>max_num)
+    max_num = 2*width;
+
+  clear_lines = (int *)calloc(max_num, sizeof(int));
+  if(clear_lines)
+    {
+      if(mode<0 || mode>=NUM_MODES)
+       mode = random()%NUM_MODES;
+      granularity = 25;
+      switch(mode)
+       {
+       case 0:
+         for(i = 0; i < height; i++)
+           clear_lines[i] = i;
+         for(i = 0; i < height; i++)
+           {
+             int t, r;
+             t = clear_lines[i];
+             r = random()%height;
+             clear_lines[i] = clear_lines[r];
+             clear_lines[r] = t;
+           }
+         num_lines = height;
+         break;
+       case 1:
+         for(i = 0; i < width; i++)
+           clear_lines[i] = i+height;
+         for(i = 0; i < width; i++)
+           {
+             int t, r;
+             t = clear_lines[i];
+             r = random()%width;
+             clear_lines[i] = clear_lines[r];
+             clear_lines[r] = t;
+           }
+         num_lines = width;
+         break;
+       case 2:
+         for(i = 0; i < width/2; i++)
+           clear_lines[i] = i*2+height;
+         for(i = 0; i < height/2; i++)
+           clear_lines[i+width/2] = i*2;
+         for(i = 0; i < width/2; i++)
+           clear_lines[i+width/2+height/2] = width-i*2-(width%2?0:1)+height;
+         num_lines = width+height/2;
+         granularity = 4;
+         break;
+       case 3:
+         for(i = 0; i < max_num/4; i++)
+           {
+             clear_lines[i*4] = i*2;
+             clear_lines[i*4+1] = height-i*2-(height%2?0:1);
+             clear_lines[i*4+2] = height+i*2;
+             clear_lines[i*4+3] = height+width-i*2-(width%2?0:1);
+           }
+         num_lines = max_num;
+         granularity = 4;
+         break;
+       case 4:
+         j = 0;
+         for(i = 0; i < width*2; i++)
+           {
+             line = (i/16)*16-(i%16)*15;
+             if(line>=0 && line<width)
+               {
+                 clear_lines[j] = height+line;
+                 j++;
+               }
+           }
+         num_lines = width;
+         granularity = 4;
+         break;
+       case 5:
+         j = 0;
+         for(i = width*2; i >= 0; i--)
+           {
+             line = (i/16)*16-(i%16)*15;
+             if(line>=0 && line<width)
+               {
+                 clear_lines[j] = height+line;
+                 j++;
+               }
+           }
+         num_lines = width;
+         granularity = 4;
+         break;
+       }
+      for (i = 0; i < num_lines; i++)
+       { 
+         if(clear_lines[i] < height)
+           XDrawLine (dpy, window, gc, 0, clear_lines[i], width, 
+                      clear_lines[i]);
+         else
+           XDrawLine (dpy, window, gc, clear_lines[i]-height, 0,
+                      clear_lines[i]-height, height);
+         XFlush (dpy);
+         if ((i % granularity) == 0)
+           {
+             usleep (delay*granularity);
+           }
+       }
+      
+      free(clear_lines);
+    }
+
+  XClearWindow (dpy, window);
+}