From 20fcffae94e2968fd9b5a09a278a35b71cab718c Mon Sep 17 00:00:00 2001
From: heckflosse <heckflosse67@gmx.de>
Date: Thu, 15 Feb 2018 13:42:10 +0100
Subject: [PATCH] Using Wavelet/Residual with contrast set to != 0 crashes on
 completely black image, fixes #4399

---
 rtengine/ipwavelet.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/rtengine/ipwavelet.cc b/rtengine/ipwavelet.cc
index ad4a169b6..572e8429e 100644
--- a/rtengine/ipwavelet.cc
+++ b/rtengine/ipwavelet.cc
@@ -1739,6 +1739,11 @@ void ImProcFunctions::WaveletcontAllL(LabImage * labco, float ** varhue, float *
 
     }
 
+    if(max0 <= 0.0) {
+        // completely black image => nothing to do
+        return;
+    }
+
     //      printf("MAXmax0=%f MINmin0=%f\n",max0,min0);
 
 //tone mapping