Floating point dng files in [0;1] range have black thumbnail, fixes #4669

rtengine/dcraw.cc

@@ -10043,29 +10043,6 @@ static void expandFloats(Bytef * dst, int tileWidth, int bytesps) {
   }
 }
 
-static void copyFloatDataToInt(float * src, ushort * dst, size_t size, float max) {
-  bool negative = false, nan = false;
-
-#ifdef _OPENMP
-#pragma omp parallel for
-#endif
-  for (size_t i = 0; i < size; ++i) {
-    if (src[i] < 0.0f) {
-      negative = true;
-      src[i] = 0.0f;
-    } else if (std::isnan(src[i])) {
-      nan = true;
-      src[i] = max;
-    }
-    // Copy the data to the integer buffer to build the thumbnail
-    dst[i] = (ushort)src[i];
-  }
-  if (negative)
-    fprintf(stderr, "DNG Float: Negative data found in input file\n");
-  if (nan)
-    fprintf(stderr, "DNG Float: NaN data found in input file\n");
-}
-
 static int decompress(size_t srcLen, size_t dstLen, unsigned char *in, unsigned char *out) {
     // At least in zlib 1.2.11 the uncompress function is not thread save while it is thread save in zlib 1.2.8
     // This simple replacement is thread save. Used example code from https://zlib.net/zlib_how.html
@@ -10207,9 +10184,6 @@ void CLASS deflate_dng_load_raw() {
 }
   }
 
-  if (ifd->sample_format == 3) {  // Floating point data
-    copyFloatDataToInt(float_raw_image, raw_image, raw_width*raw_height, maximum);
-  }
 }
 
 /* RT: removed unused functions */

rtengine/rawimage.h

@@ -167,10 +167,22 @@ public:
     {
         return top_margin;
     }
+
+    int get_rawwidth() const
+    {
+        return raw_width;
+    }
+
     int get_FujiWidth() const
     {
         return fuji_width;
     }
+
+    float const * get_FloatRawImage() const
+    {
+        return float_raw_image;
+    }
+
     eSensorType getSensorType();
 
     void getRgbCam (float rgbcam[3][4]);
@@ -312,6 +324,11 @@ public:
         return filters == 9;
     }
 
+    bool isFloat() const
+    {
+        return float_raw_image;
+    }
+
 public:
     // dcraw functions
     void pre_interpolate()

rtengine/rtthumbnail.cc

@@ -66,7 +66,11 @@ void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4],
     if (ri->isBayer()) {
         const int height = ri->get_iheight();
         const int width = ri->get_iwidth();
-
+        const bool isFloat = ri->isFloat();
+        const int top_margin = ri->get_topmargin();
+        const int left_margin = ri->get_leftmargin();
+        const int raw_width = ri->get_rawwidth();
+        const float * const float_raw_image = ri->get_FloatRawImage();
 #ifdef _OPENMP
         #pragma omp parallel for if(multiThread)
 #endif
@@ -76,8 +80,15 @@ void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4],
             int col = 0;
 
             for (; col < width - 1; col += 2) {
-                float val0 = image[row * width + col][c0];
+                float val0;
-                float val1 = image[row * width + col + 1][c1];
+                float val1;
+                if (isFloat) {
+                    val0 = float_raw_image[(row + top_margin) * raw_width + col + left_margin];
+                    val1 = float_raw_image[(row + top_margin) * raw_width + col + left_margin + 1];
+                } else {
+                    val0 = image[row * width + col][c0];
+                    val1 = image[row * width + col + 1][c1];
+                }
                 val0 -= cblack[c0];
                 val1 -= cblack[c1];
                 val0 *= scale_mul[c0];
@@ -87,7 +98,12 @@ void scale_colors (rtengine::RawImage *ri, float scale_mul[4], float cblack[4],
             }
 
             if (col < width) { // in case width is odd
-                float val0 = image[row * width + col][c0];
+                float val0;
+                if (isFloat) {
+                    val0 = float_raw_image[(row + top_margin) * raw_width + col + left_margin];
+                } else {
+                    val0 = image[row * width + col][c0];
+                }
                 val0 -= cblack[c0];
                 val0 *= scale_mul[c0];
                 image[row * width + col][c0] = rtengine::CLIP (val0);