Non-cyclic contour hue

[jschueller]

What happened?

An idea mentioned by Regis to improve readability of contour plots was to avoid purple colors

But this clashes with #2587

How to reproduce the issue?

diff --git a/lib/src/Base/Func/EvaluationImplementation.cxx b/lib/src/Base/Func/EvaluationImplementation.cxx
index a56d7f823..5d6437c9b 100644
--- a/lib/src/Base/Func/EvaluationImplementation.cxx
+++ b/lib/src/Base/Func/EvaluationImplementation.cxx
@@ -447,7 +447,7 @@ Graph EvaluationImplementation::draw(const UnsignedInteger firstInputMarginal,
     current.setLabels(Description(1, labels[i]));
     current.setDrawLabels(false);
     current.setLegend(labels[i]);
-    current.setColor(Contour::ConvertFromHSV((360.0 * i / levels.getDimension()), 1.0, 1.0));
+    current.setColor(Contour::ConvertFromHSV((270.0 * i / levels.getDimension()), 1.0, 1.0));
     graph.add(current);
   }
   return graph;
diff --git a/lib/src/Base/Stat/CovarianceModelImplementation.cxx b/lib/src/Base/Stat/CovarianceModelImplementation.cxx
index 96f26e59c..f153e4c8f 100644
--- a/lib/src/Base/Stat/CovarianceModelImplementation.cxx
+++ b/lib/src/Base/Stat/CovarianceModelImplementation.cxx
@@ -1277,7 +1277,7 @@ Graph CovarianceModelImplementation::draw(const UnsignedInteger rowIndex,
     current.setLabels(Description(1, labels[i]));
     current.setDrawLabels(false);
     current.setLegend(labels[i]);
-    current.setColor(Contour::ConvertFromHSV((360.0 * i / levels.getDimension()), 1.0, 1.0));
+    current.setColor(Contour::ConvertFromHSV((270.0 * i / levels.getDimension()), 1.0, 1.0));
     graph.add(current);
   }
   return graph;

[regislebrun]

@jschueller In the HSV color space the hue is divided into 6 sectors bounded by the primary and complementary colors. The idea I had was to remove the last sector, so 360.0 should be replaced by 300.0 and not 270.0.
I checked it on the NormalGamma PDF and it looks good to me. The last color is violet, quite far away from red

[josephmure]

Imo this issue is fixed by #2587 because it allows the user to select different (usually better) color maps than HSV.