[Plplot-cvs] SF.net SVN: plplot:[10356] trunk/src/plctrl.c

[<ai...@us...>]

Revision: 10356
          http://plplot.svn.sourceforge.net/plplot/?rev=10356&view=rev
Author:   airwin
Date:     2009-08-28 17:45:15 +0000 (Fri, 28 Aug 2009)

Log Message:
-----------
Coarsen fuzzy range checks so they will work even in the single-precision
(32-bit floating point) case.  Thanks to Arjen for pointing out this
potential issue.

Modified Paths:
--------------
    trunk/src/plctrl.c

Modified: trunk/src/plctrl.c
===================================================================
--- trunk/src/plctrl.c	2009-08-28 17:07:01 UTC (rev 10355)
+++ trunk/src/plctrl.c	2009-08-28 17:45:15 UTC (rev 10356)
@@ -56,6 +56,10 @@
 
 #define BUFFER_SIZE 256
 
+/* small epsilon for fuzzy range checks that is still large enough to
+   work even in the single precision floating point case.*/
+#define FUZZ_EPSILON 1.e-4
+
 /* Static functions */
 
 /* Used by any external init code to suggest a path */
@@ -1254,7 +1258,7 @@
           break;
         }
         /* fuzzy range check. */
-        if(*(*a+i) < -1.e-12 || *(*a+i) > (1. + 1.e-12)) {
+        if(*(*a+i) < -FUZZ_EPSILON || *(*a+i) > (1. + FUZZ_EPSILON)) {
           err = 1;
           break;
         } else if(*(*a+i) < 0.) {
@@ -1442,10 +1446,10 @@
       b[i] = (PLFLT)b_i/255.;
       a[i] = 1.0;
       pos[i] = 0.01*(PLFLT)pos_i;
-      fuzzy_range_check(r[i], 0., 1., 1.e-12, 1);
-      fuzzy_range_check(g[i], 0., 1., 1.e-12, 2);
-      fuzzy_range_check(b[i], 0., 1., 1.e-12, 3);
-      fuzzy_range_check(pos[i], 0., 1., 1.e-12, 4);
+      fuzzy_range_check(r[i], 0., 1., FUZZ_EPSILON, 1);
+      fuzzy_range_check(g[i], 0., 1., FUZZ_EPSILON, 2);
+      fuzzy_range_check(b[i], 0., 1., FUZZ_EPSILON, 3);
+      fuzzy_range_check(pos[i], 0., 1., FUZZ_EPSILON, 4);
       if(return_sscanf == 5) {
         /* Next to oldest tk format with rev specified. */
         rev[i] = (PLBOOL)rev_i;
@@ -1477,14 +1481,14 @@
          1. except for the hls colour space case where the first
          coordinate is checked within range from 0. to 360.*/
       if(rgb) {
-        fuzzy_range_check(r[i], 0., 1., 1.e-12, 5);
+        fuzzy_range_check(r[i], 0., 1., FUZZ_EPSILON, 5);
       } else {
-        fuzzy_range_check(r[i], 0., 360., 360.e-12, 6);
+        fuzzy_range_check(r[i], 0., 360., (360.*FUZZ_EPSILON), 6);
       }
-      fuzzy_range_check(g[i], 0., 1., 1.e-12, 7);
-      fuzzy_range_check(b[i], 0., 1., 1.e-12, 8);
-      fuzzy_range_check(a[i], 0., 1., 1.e-12, 9);
-      fuzzy_range_check(pos[i], 0., 1., 1.e-12, 10);
+      fuzzy_range_check(g[i], 0., 1., FUZZ_EPSILON, 7);
+      fuzzy_range_check(b[i], 0., 1., FUZZ_EPSILON, 8);
+      fuzzy_range_check(a[i], 0., 1., FUZZ_EPSILON, 9);
+      fuzzy_range_check(pos[i], 0., 1., FUZZ_EPSILON, 10);
       
       rev[i] = (PLBOOL)rev_i;
     }


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