Fix new color propagation method (#6109)

* Fixed artifacts thanks to Alberto

* Added blur to Color propagation

* Clean format code - small improvments

* color propagation: Enable old mode at blur = 0

* Improve GUI

* color propagation: smooth progress bar for blur > 0

* change label

* Some cleanups

* color propagation: small speedup for blur > 0

* color propagation: speedup for blur > 0 when region with clipped highlights is small

* Speed-up for blur=1 - clean GUI code

* color propagation: cleanups

* Harmonize events in tonecurve.cc

* tonecurve.cc : cleanup

* Highlight reconstruction: small changes to gui

* Use Gtk::Box instead of Gtk::VBox

* Change maximum number of blur levels to 4

* Suppress BENCHFUN

* Suppress bad commit locallabtools

Co-authored-by: Desmis <jdesmis@gmail.com>
Co-authored-by: Ingo Weyrich <heckflosse67@gmx.de>

rtengine/color.h

@@ -206,6 +206,11 @@ public:
         return static_cast<double>(r) * workingspace[1][0] + static_cast<double>(g) * workingspace[1][1] + static_cast<double>(b) * workingspace[1][2];
     }
 
+    static float rgbLuminance(float r, float g, float b, const float workingspace[3])
+    {
+        return r * workingspace[0] + g * workingspace[1] + b * workingspace[2];
+    }
+
 #ifdef __SSE2__
     static vfloat rgbLuminance(vfloat r, vfloat g, vfloat b, const vfloat workingspace[3])
     {