public void TestDrawRgbColorMatrix()
{
// init three matrices
double[,] redM = new double[5, 5];
double[,] grnM = new double[5, 5];
double[,] bluM = new double[5, 5];
//convert some values to null or NaN
redM[1, 1] = double.NaN;
grnM[1, 1] = double.NaN;
bluM[1, 1] = double.NaN;
redM[2, 2] = 1.0;
grnM[2, 2] = 1.0;
bluM[2, 2] = double.NaN;
redM[3, 3] = 0.01;
grnM[3, 3] = 0.01;
bluM[3, 3] = 0.11;
var blueEnhanceParameter = 0.0;
var image = (Bitmap)LDSpectrogramRGB.DrawRgbColorMatrix(redM, grnM, bluM, doReverseColor: true, blueEnhanceParameter);
Assert.That.PixelIsColor(new Point(1, 1), Color.FromArgb(128, 128, 128), image);
Assert.That.PixelIsColor(new Point(2, 2), Color.FromArgb(128, 128, 128), image);
// empty values are rendered as white because of `doReverseColour`
Assert.That.ImageRegionIsColor(Rectangle.FromLTRB(0, 0, 1, 5), Color.FromArgb(255, 255, 255), image);
Assert.That.ImageRegionIsColor(Rectangle.FromLTRB(4, 0, 5, 5), Color.FromArgb(255, 255, 255), image);
}