From e7dcacdb43b2f78b6fdc47480e064df07e0f53d7 Mon Sep 17 00:00:00 2001
From: Emil Martinec <ejmartin@uchicago.edu>
Date: Thu, 23 Sep 2010 01:17:51 -0500
Subject: [PATCH] Patch for issue 186 -- blue pixels appearing when "avoid
 color clipping" is selected for the color boost tool, and black point is
 nonzero.  Problem was roundoff error.

---
 rtengine/improcfun.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/rtengine/improcfun.cc b/rtengine/improcfun.cc
index 26db61a73..58c323b05 100644
--- a/rtengine/improcfun.cc
+++ b/rtengine/improcfun.cc
@@ -390,7 +390,8 @@ void ImProcFunctions::colorCurve (LabImage* lold, LabImage* lnew) {
         }
     }
     
-    double shift_a = params->colorShift.a * chroma_scale, shift_b = params->colorShift.b * chroma_scale;
+	float eps = 0.001;
+    double shift_a = params->colorShift.a * chroma_scale + eps, shift_b = params->colorShift.b * chroma_scale + eps;
 
     short** oa = lold->a;
     short** ob = lold->b;