http://packetstormsecurity.org/UNIX/admin/xscreensaver-4.01.tar.gz

[xscreensaver] / hacks / xspirograph.c

diff --git a/hacks/xspirograph.c b/hacks/xspirograph.c
index 0853faa580812cfd98583b281ba99e577e67bae9..2cc52f283a8a83b0fc5a1775d955c237ff174b40 100644 (file)
--- a/hacks/xspirograph.c
+++ b/hacks/xspirograph.c
@@ -12,6 +12,10 @@
  * documentation.  No representations are made about the suitability of this
  * software for any purpose.  It is provided "as is" without express or 
  * implied warranty.
+ *
+ * Modified (Dec 2001) by Matthew Strait <straitm@mathcs.carleton.edu>
+ * Added -subdelay and -alwaysfinish
+ * Prevented redrawing over existing lines
  */
 
 #include <math.h>
@@ -20,8 +24,10 @@
 
 static GC      draw_gc;
 static int     sleep_time;
+static int     sub_sleep_time;
 static int     num_layers;
 static unsigned int default_fg_pixel;
+static Bool    always_finish_p;
 
 static void
 init_tsg (Display *dpy, Window window)
@@ -48,6 +54,8 @@ go (Display *dpy, Window window,
   int width, height;
   int xmid, ymid;
   int x1, y1, x2, y2;
+  float firstx = 0, firsty = 0;
+  float tmpx, tmpy;
   int theta;
   int delta;
 
@@ -62,9 +70,10 @@ go (Display *dpy, Window window,
   y1 = ymid;
 
 
-  for (theta = 1; theta < ( 360 * 100 ); theta++)
+  for (theta = 1; /* theta < ( 360 * 100 ) */; theta++) 
+                  /* see below about alwaysfinish */
     {
-       x2 = xmid + ((       radius1              /* * * * *            */
+       tmpx = xmid + ((       radius1            /* * * * *            */
                   - radius2        )            /* This algo simulates */
                   * cos((      theta           /* the rotation of a    */
                   * M_PI           )           /* circular disk inside */
@@ -78,7 +87,7 @@ go (Display *dpy, Window window,
                   / 180            )            /* of delta needs to be */
                                    );           /* given, which greatly */
                                                /* adds to the beauty   */
-       y2 = ymid + (                           /* of the figure.       */
+       tmpy = ymid + (                         /* of the figure.       */
                      ( radius1 - radius2       /*                      */
                       ) * sin                  /* Imperfection adds to */
                        (                       /* beauty, symbolically */
@@ -96,14 +105,39 @@ go (Display *dpy, Window window,
                                    ) * M_PI / 180
                                     )
                                      );
-                               
+        
+       /*makes integers from the calculated values to do the drawing*/
+       x2 = tmpx;
+       y2 = tmpy;
+
+       /*stores the first values for later reference*/
+       if(theta == 1)
+       {
+               firstx = tmpx;
+               firsty = tmpy;
+       }
 
         XDrawLine (dpy, window, draw_gc, x1, y1, x2, y2);
 
        x1 = x2;
        y1 = y2;
         XFlush (dpy);
-    }
+
+       /* compares the exact values calculated to the first
+          exact values calculated */
+       /* this will break when nothing new is being drawn */
+       if(tmpx == firstx && tmpy == firsty && theta != 1)
+               break;
+
+       /* this will break after 36000 iterations if 
+          the -alwaysfinish option is not specified */
+       if(!always_finish_p && theta > ( 360 * 100 ) )
+               break;
+
+       /* usleeping every time is too slow */
+       if(theta%100 == 0)
+               usleep(sub_sleep_time);
+    }  
 }
 
 
@@ -130,7 +164,7 @@ getset (Display *dpy, Window window, XColor *color, Bool *got_color)
   XClearWindow (dpy, window);
 
 
-  for(counter = 0; counter < num_layers; counter ++)
+  for(counter = 0; counter < num_layers; counter++)
   {
     divisor = ((frand (3.0) + 1) * (((random() & 1) * 2) - 1));
 
@@ -149,6 +183,7 @@ getset (Display *dpy, Window window, XColor *color, Bool *got_color)
       else
        XSetForeground (dpy, draw_gc, default_fg_pixel);
     }
+
     go (dpy, window, radius1, -radius2, distance);
 
     /* once again, with a parameter negated, just for kicks */
@@ -163,6 +198,7 @@ getset (Display *dpy, Window window, XColor *color, Bool *got_color)
       else
        XSetForeground (dpy, draw_gc, default_fg_pixel);
     }
+
     go (dpy, window, radius1, radius2, distance);
   }
 }
@@ -201,15 +237,20 @@ getset_go (Display *dpy, Window window)
 char *progclass = "XSpiroGraph";
 
 char *defaults [] = {
-  ".background: black",
-  "*delay:      5",
-  "*layers:     1",
+  ".background:                black",
+  "*delay:             5",
+  "*subdelay:          0",
+  "*layers:            1",
+  "*alwaysfinish:      false",
   0
 };
 
 XrmOptionDescRec options [] = {   
   { "-delay",           ".delay",               XrmoptionSepArg, 0 },
-  { "-layers",          ".layers",              XrmoptionSepArg, 0 },
+  { "-subdelay",        ".subdelay",            XrmoptionSepArg, 0 },
+  { "-layers",          ".layers",             XrmoptionSepArg, 0 },
+  { "-alwaysfinish",    ".alwaysfinish",       XrmoptionNoArg, "true"},
+  { "-noalwaysfinish",  ".alwaysfinish",       XrmoptionNoArg, "false"},
   { 0, 0, 0, 0 }
 };
 int options_size = (sizeof (options) / sizeof (options[0]));
@@ -218,7 +259,10 @@ void
 screenhack (Display *dpy, Window window)
 {
   sleep_time = get_integer_resource("delay", "Integer");
+  sub_sleep_time = get_integer_resource("subdelay", "Integer");
   num_layers = get_integer_resource("layers", "Integer");
+  always_finish_p = get_boolean_resource ("alwaysfinish", "Boolean");
+  
   init_tsg (dpy, window);
   while (1)
    getset_go (dpy, window);