Merge pull request matplotlib#28707 from jsspencer/fix_sketch_divide_by_zero

Avoid division-by-zero in Sketch::Sketch

Author: ksunden

src/path_converters.h

@@ -5,6 +5,7 @@
 
 #include <cmath>
 #include <cstdint>
+#include <limits>
 
 #include "agg_clip_liang_barsky.h"
 #include "mplutils.h"
@@ -1019,8 +1020,18 @@ class Sketch
     {
         rewind(0);
         const double d_M_PI = 3.14159265358979323846;
-        m_p_scale = (2.0 * d_M_PI) / (m_length * m_randomness);
-        m_log_randomness = 2.0 * log(m_randomness);
+        // Set derived values to zero if m_length or m_randomness are zero to
+        // avoid divide-by-zero errors when a sketch is created but not used.
+        if (m_length <= std::numeric_limits<double>::epsilon() || m_randomness <= std::numeric_limits<double>::epsilon()) {
+            m_p_scale = 0.0;
+        } else {
+            m_p_scale = (2.0 * d_M_PI) / (m_length * m_randomness);
+        }
+        if (m_randomness <= std::numeric_limits<double>::epsilon()) {
+            m_log_randomness = 0.0;
+        } else {
+            m_log_randomness = 2.0 * log(m_randomness);
+        }
     }
 
     unsigned vertex(double *x, double *y)