# HG changeset patch
# User Sebastien Jodogne <s.jodogne@gmail.com>
# Date 1592845449 -7200
# Node ID f18eaade61538527ad59135e591b2ed64b12b65c
# Parent  73c22208272f4c18b01b50386003b066b08fb298
simplification in ImageProcessing::ShiftScale()

diff -r 73c22208272f -r f18eaade6153 Core/Images/ImageProcessing.cpp
--- a/Core/Images/ImageProcessing.cpp	Mon Jun 22 18:59:45 2020 +0200
+++ b/Core/Images/ImageProcessing.cpp	Mon Jun 22 19:04:09 2020 +0200
@@ -386,7 +386,8 @@
 
 
   // Computes "a * x + b" at each pixel => Note that this is not the
-  // same convention as in "ShiftScale()"
+  // same convention as in "ShiftScale()", but it is the convention of
+  // "ShiftScale2()"
   template <typename TargetType,
             typename SourceType,
             bool UseRound,
@@ -1367,15 +1368,14 @@
   }
 
 
-  void ImageProcessing::ShiftScale(ImageAccessor& image,
-                                   float offset,
-                                   float scaling,
-                                   bool useRound)
+  void ImageProcessing::ShiftScale2(ImageAccessor& image,
+                                    float offset,
+                                    float scaling,
+                                    bool useRound)
   {
-    // Rewrite "(x + offset) * scaling" as "a * x + b"
-
+    // We compute "a * x + b"
     const float a = scaling;
-    const float b = offset * scaling;
+    const float b = offset;
     
     switch (image.GetFormat())
     {
@@ -1430,16 +1430,15 @@
   }
 
 
-  void ImageProcessing::ShiftScale(ImageAccessor& target,
-                                   const ImageAccessor& source,
-                                   float offset,
-                                   float scaling,
-                                   bool useRound)
+  void ImageProcessing::ShiftScale2(ImageAccessor& target,
+                                    const ImageAccessor& source,
+                                    float offset,
+                                    float scaling,
+                                    bool useRound)
   {
-    // Rewrite "(x + offset) * scaling" as "a * x + b"
-
+    // We compute "a * x + b"
     const float a = scaling;
-    const float b = offset * scaling;
+    const float b = offset;
     
     switch (target.GetFormat())
     {
@@ -1470,36 +1469,30 @@
   }
 
 
-  void ImageProcessing::ShiftScale2(ImageAccessor& image,
-                                    float offset,
-                                    float scaling,
-                                    bool useRound)
+  void ImageProcessing::ShiftScale(ImageAccessor& image,
+                                   float offset,
+                                   float scaling,
+                                   bool useRound)
   {
-    if (std::abs(scaling) < 0.001f)
-    {
-      Set(image, offset);
-    }
-    else
-    {
-      ShiftScale(image, offset / scaling, scaling, useRound);
-    }
+    // Rewrite "(x + offset) * scaling" as "a * x + b"
+
+    const float a = scaling;
+    const float b = offset * scaling;
+    ShiftScale2(image, b, a, useRound);
   }
 
 
-  void ImageProcessing::ShiftScale2(ImageAccessor& target,
-                                    const ImageAccessor& source,
-                                    float offset,
-                                    float scaling,
-                                    bool useRound)
+  void ImageProcessing::ShiftScale(ImageAccessor& target,
+                                   const ImageAccessor& source,
+                                   float offset,
+                                   float scaling,
+                                   bool useRound)
   {
-    if (std::abs(scaling) < 0.0001f)
-    {
-      Set(target, offset);
-    }
-    else
-    {
-      ShiftScale(target, source, offset / scaling, scaling, useRound);
-    }
+    // Rewrite "(x + offset) * scaling" as "a * x + b"
+
+    const float a = scaling;
+    const float b = offset * scaling;
+    ShiftScale2(target, source, b, a, useRound);
   }