From 95f3eaf001188a1e098bea246e6736751e5fcd0d Mon Sep 17 00:00:00 2001
From: Morgan Hardwood <bugs@londonlight.org>
Date: Wed, 31 May 2017 18:55:41 +0200
Subject: [PATCH] Diagonal curve should be bypassed when it is linear,
 regardless of node count, fixes #3902

---
 rtengine/diagonalcurves.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rtengine/diagonalcurves.cc b/rtengine/diagonalcurves.cc
index 1c75e3059..82faa6cd5 100644
--- a/rtengine/diagonalcurves.cc
+++ b/rtengine/diagonalcurves.cc
@@ -58,7 +58,7 @@ DiagonalCurve::DiagonalCurve (const std::vector<double>& p, int poly_pn)
                 x[i] = p[ix++];
                 y[i] = p[ix++];
 
-                if (x[i] != y[i]) {
+                if (std::fabs(x[i] - y[i]) >= 0.000009) {
                     identity = false;
                 }
             }