From 18f09dcbee6dfd466022e13eb80f3882dd2076ce Mon Sep 17 00:00:00 2001
From: heckflosse <heckflosse67@gmx.de>
Date: Sat, 23 Sep 2017 16:20:50 +0200
Subject: [PATCH] Fix wrong thumbnails for Canon G3 and G5, fixes #4000, fixes
 #4099

---
 rtengine/rawimage.cc | 13 +++++++++----
 rtengine/rawimage.h  |  2 +-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/rtengine/rawimage.cc b/rtengine/rawimage.cc
index f36e798d9..de392623d 100644
--- a/rtengine/rawimage.cc
+++ b/rtengine/rawimage.cc
@@ -112,7 +112,10 @@ void RawImage::get_colorsCoeff( float *pre_mul_, float *scale_mul_, float *cblac
         }
     }
 
-    if (data && (this->get_cam_mul(0) == -1 || forceAutoWB)) {
+    if (this->get_cam_mul(0) == -1 || forceAutoWB) {
+        if(!data) { // this happens only for thumbnail creation when get_cam_mul(0) == -1
+            compress_image(0, false);
+        }
         memset(dsum, 0, sizeof dsum);
 
         if (this->isBayer()) {
@@ -673,7 +676,7 @@ int RawImage::loadRaw (bool loadData, unsigned int imageNum, bool closeFile, Pro
     return 0;
 }
 
-float** RawImage::compress_image(int frameNum)
+float** RawImage::compress_image(int frameNum, bool freeImage)
 {
     if( !image ) {
         return nullptr;
@@ -757,8 +760,10 @@ float** RawImage::compress_image(int frameNum)
             }
     }
 
-    free(image); // we don't need this anymore
-    image = nullptr;
+    if(freeImage) {
+        free(image); // we don't need this anymore
+        image = nullptr;
+    }
     return data;
 }
 
diff --git a/rtengine/rawimage.h b/rtengine/rawimage.h
index c2cdcb6ec..b8a45d708 100644
--- a/rtengine/rawimage.h
+++ b/rtengine/rawimage.h
@@ -121,7 +121,7 @@ public:
     {
         return image;
     }
-    float** compress_image(int frameNum); // revert to compressed pixels format and release image data
+    float** compress_image(int frameNum, bool freeImage = true); // revert to compressed pixels format and release image data
     float** data;             // holds pixel values, data[i][j] corresponds to the ith row and jth column
     unsigned prefilters;               // original filters saved ( used for 4 color processing )
     unsigned int getFrameCount() const { return is_raw; }