From 6433a64f4cd41e88499386b0b7c7ae05d30683b8 Mon Sep 17 00:00:00 2001 From: Tom Hughes Date: Sat, 22 Jun 2013 12:33:32 +0100 Subject: [PATCH 14/15] Avoid potential zero division resulting in nan in agg::gamma_linear --- include/agg_gamma_functions.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/agg_gamma_functions.h b/include/agg_gamma_functions.h index fa38a45..beb0c04 100644 --- a/include/agg_gamma_functions.h +++ b/include/agg_gamma_functions.h @@ -94,7 +94,11 @@ namespace agg { if(x < m_start) return 0.0; if(x > m_end) return 1.0; - return (x - m_start) / (m_end - m_start); + double delta = m_end - m_start; + // avoid nan from potential zero division + // https://github.com/mapnik/mapnik/issues/761 + if (delta <= 0.0) return 0.0; + return (x - m_start) / delta; } private: -- 1.8.1.4