[Groff-commit] groff ChangeLog src/preproc/pic/object.cpp

[Werner LEMBERG]

CVSROOT:        /cvsroot/groff
Module name:    groff
Changes by:     Werner LEMBERG <wl>     09/09/01 05:26:33

Modified files:
        .              : ChangeLog 
        src/preproc/pic: object.cpp 

Log message:
        [pic] Fix a border case for arc computation.
        
        * src/preproc/pic/object.cpp (object_spec::make_arc): It can happen
        that test `radius < d' in the loop is satisfied, but the difference
        in the two values is on the order of 1e-10.  If `radius' is small,
        doubling the value can lead to a fairly gross error.
        
        The original code appears to have been intended to deal with the
        situation when radius is orders of magnitude less than `d'.  The
        replacement code simply assigns `radius' the smallest value that
        avoids problems with the floating point code further on in the
        routine.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/groff/ChangeLog?cvsroot=groff&r1=1.1208&r2=1.1209
http://cvs.savannah.gnu.org/viewcvs/groff/src/preproc/pic/object.cpp?cvsroot=groff&r1=1.11&r2=1.12

Patches:
Index: ChangeLog
===================================================================
RCS file: /cvsroot/groff/groff/ChangeLog,v
retrieving revision 1.1208
retrieving revision 1.1209
diff -u -b -r1.1208 -r1.1209
--- ChangeLog   14 Aug 2009 18:14:47 -0000      1.1208
+++ ChangeLog   1 Sep 2009 05:26:30 -0000       1.1209
@@ -1,3 +1,18 @@
+2009-09-01  Michael Cain  <address@hidden>
+
+       [pic] Fix a border case for arc computation.
+
+       * src/preproc/pic/object.cpp (object_spec::make_arc): It can happen
+       that test `radius < d' in the loop is satisfied, but the difference
+       in the two values is on the order of 1e-10.  If `radius' is small,
+       doubling the value can lead to a fairly gross error.
+
+       The original code appears to have been intended to deal with the
+       situation when radius is orders of magnitude less than `d'.  The
+       replacement code simply assigns `radius' the smallest value that
+       avoids problems with the floating point code further on in the
+       routine.
+
 2009-08-14  Roger Leigh <address@hidden>
 
        * man/groff_char.man: Fix white heart and diamond unicode values.

Index: src/preproc/pic/object.cpp
===================================================================
RCS file: /cvsroot/groff/groff/src/preproc/pic/object.cpp,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -b -r1.11 -r1.12
--- src/preproc/pic/object.cpp  5 Jan 2009 20:11:08 -0000       1.11
+++ src/preproc/pic/object.cpp  1 Sep 2009 05:26:32 -0000       1.12
@@ -1830,8 +1830,8 @@
     if (radius <= 0)
       radius = .25;
     // make the radius big enough
-    while (radius < d)
-      radius *= 2.0;
+    if (radius < d)
+      radius = d;
     double alpha = acos(d/radius);
     double theta = atan2(h.y, h.x);
     if (cw)