prepared algorithm for custom pseudo color

app/Operations/PseudoColorOp.cpp

@@ -33,16 +33,27 @@ bool PseudoColorOp::needCurrentImg() const {
     return true;
 }
 
+static int getLinearHue(int value, int nhue){
+    return floor(value * nhue / 255);
+}
+
 void PseudoColorOp::operator()(const imagein::Image* image, const std::map<const imagein::Image*, std::string>&) {
-   GrayscaleImage* tmpImg = Converter<GrayscaleImage>::convert(*image);
-   Image* resImg = new Image(tmpImg->getWidth(), tmpImg->getHeight(), 3);
+    GrayscaleImage* tmpImg = Converter<GrayscaleImage>::convert(*image);
+    Image* resImg = new Image(tmpImg->getWidth(), tmpImg->getHeight(), 3);
+
+    int nhue = 255; // changer cette valeur en fonction de la fenêtre de dialog
+
+    int (*getHue)(int a, int b);
+
+    getHue = getLinearHue;
+
     for(unsigned int j = 0; j < tmpImg->getHeight(); ++j) {
         for(unsigned int i = 0; i < tmpImg->getWidth(); ++i) {
             Image::depth_t value = tmpImg->getPixel(i, j);
-            const int nhue = 256;
-            const int ngrad = ceil(256. / (double)nhue);
-            const int hue = floor(value * nhue / 256); /* € [0, nhue[ */
-            const int grad = value - ceil((double)hue * 256. / (double)nhue); /* € [0, ngrad[ */
+            
+            const int ngrad = ceil(255. / (double)nhue);
+            const int hue =  getHue(value, nhue); /* € [0, nhue[ */
+            const int grad = value - ceil((double)hue * 255 / (double)nhue); /* € [0, ngrad[ */
             QColor color = QColor::fromHsl(300 - hue * 300 / nhue, 255, (grad + 1) * 255 / (ngrad + 1));
             resImg->setPixel(i, j, 0, color.red());
             resImg->setPixel(i, j, 1, color.green());