X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=hacks%2Fxlyap.c;h=ab7fde5db42b3fd1120da61a1732129284b762bd;hb=06e9a7886a77cad92f9ddbc169d6d199a4d8b76d;hp=a343cfff4759176ddd169b117aa5c9e49a329625;hpb=c6b273ef7292ba10943694df1656b05203d7b62f;p=xscreensaver

diff --git a/hacks/xlyap.c b/hacks/xlyap.c
index a343cfff..ab7fde5d 100644
--- a/hacks/xlyap.c
+++ b/hacks/xlyap.c
@@ -47,8 +47,8 @@
 char *progclass = "XLyap";
 
 char *defaults [] = {
-  "*background:		black",
-  "*foreground:		white",
+  ".background:		black",
+  ".foreground:		white",
   "*randomize:		false",
   "*builtin:		-1",
   "*minColor:		1",
@@ -582,6 +582,9 @@ main_event(void)
 	  break;
 	    case ButtonRelease:
     EndRubberBand(canvas, &rubber_data, &event);
+	  break;
+            default: 
+    screenhack_handle_event (dpy, &event);
 	  break;
 	    }
 	}
@@ -596,13 +599,13 @@ main_event(void)
 static int
 complyap(void)
 {
-  register i, bindex;
-  double total, prod, x, r;
+  int i, bindex;
+  double total, prod, x, dx, r;
 
   if (!run)
     return TRUE;
   a += a_inc;
-  if (a >= max_a)
+  if (a >= max_a) {
     if (sendpoint(lyapunov) == TRUE)
       return FALSE;
     else {
@@ -611,6 +614,7 @@ complyap(void)
 	save_to_file();
       return TRUE;
     }
+  }
   if (b >= max_b) {
     FlushBuffer();
     if (savefile)
@@ -646,7 +650,14 @@ complyap(void)
   if (useprod) {      /* using log(a*b) */
     for (i=0;i<dwell;i++) {
       x = (*map)(x, r);
-      prod *= ABS((*deriv)(x, r));
+      dx = (*deriv)(x, r); /* ABS is a macro, so don't be fancy */
+      dx = ABS(dx);
+      if (dx == 0.0) /* log(0) is nasty so break out. */
+      {
+        i++;
+        break;
+      }
+      prod *= dx;
       /* we need to prevent overflow and underflow */
       if ((prod > 1.0e12) || (prod < 1.0e-12)) {
 	total += log(prod);
@@ -666,12 +677,19 @@ complyap(void)
 #endif
     }
     total += log(prod);
-    lyapunov = (total * M_LOG2E) / (double)dwell;
+    lyapunov = (total * M_LOG2E) / (double)i;   
   }
   else {	/* use log(a) + log(b) */
     for (i=0;i<dwell;i++) {
       x = (*map)(x, r);
-      total += log(ABS((*deriv)(x, r)));
+      dx = (*deriv)(x, r); /* ABS is a macro, so don't be fancy */
+      dx = ABS(dx);
+      if (x == 0.0)  /* log(0) check */
+      {
+        i++;
+        break;
+      }
+      total += log(dx);
       if (++bindex >= maxindex) {
 	bindex = 0;
 	if (Rflag)
@@ -685,8 +703,9 @@ complyap(void)
       deriv = Derivs[Forcing[findex]];
 #endif
     }
-    lyapunov = (total * M_LOG2E) / (double)dwell;
+    lyapunov = (total * M_LOG2E) / (double)i;
   }
+
   if (sendpoint(lyapunov) == TRUE)
     return FALSE;
   else {
@@ -1422,6 +1441,15 @@ sendpoint(double expo)
   static int index;
   static double tmpexpo;
 
+#if 0
+/* The relationship minexp <= expo <= maxexp should always be true. This test
+   enforces that. But maybe not enforcing it makes better pictures. */
+  if (expo < minexp)
+    expo = minexp;
+  else if (expo > maxexp)
+    expo = maxexp;
+#endif
+
   point.x++;
   tmpexpo = (negative) ? expo : -1.0 * expo;
   if (tmpexpo > 0) {
@@ -1854,6 +1882,14 @@ InitBuffer(void)
 static void
 BufferPoint(Display *display, Window window, int color, int x, int y)
 {
+
+/* Guard against bogus color values. Shouldn't be necessary but paranoia
+   is good. */
+  if (color < 0)
+    color = 0;
+  else if (color >= maxcolor)
+    color = maxcolor - 1;
+
   if (Points.npoints[color] == MAXPOINTS)
   {
     XDrawPoints(display, window, Data_GC[color],