Change the Color Map of the Intensity Graph at Run-time

[PLK]

Hello,

Recently I've found out that the ColorScale class of the Intensity Graph has the ColorMap property as a read-only one. I am wondering if it is any way to change the ColorMap of the Intensity Graph at Run-time.

Thank you in advance.

[Alex+ra]

Hi PLK,

I was able to change the ColorMap property of the IntensityPlot (a member of the Intensity Graph) using the following code (in C#, MStudio 2012, VStudio 2010):

intensityPlot1.ColorScale.ColorMap.Add(0, Color.FromArgb(redValue[0], greenValue[0], blueValue[0]));
intensityPlot1.ColorScale.ColorMap.Add(50, Color.FromArgb(redValue[1], greenValue[1], blueValue[1]));
intensityPlot1.ColorScale.ColorMap.Add(100, Color.FromArgb(redValue[2], greenValue[2], blueValue[2]));

If you try to change the intensityGraph1.ColorScale.ColorMap, the scale and plot won't line up. You have to change the color scale of the plot to see a change, and the color scale of the graph to change the legend. 

Let me know if this gets you going in the right direction!

Regards,

Alexandra 

[PLK]

Hi Alexandra,

Thanks for the right direction you have guided me to. In my opinion, it is more advantageous to use the AddRange member of the ColorMap object. It will add a whole color map at once. So, I've ended up with the following:

// Create the small Rainbow color map

double ScaleMin=intensityPlot1.ColorScale.Range.Minimum;

double ScaleMax=intensityPlot1.ColorScale.Range.Maximum;

double valLen=ScaleMax-ScaleMin;

double[] values={ScaleMin,ScaleMin+valLen/4,ScaleMin+valLen/2,ScaleMin+valLen/4*3,ScaleMax};

Color[] colors={Color.FromArgb(0,0,255),Color.FromArgb(0,255,255),Color.FromArgb(0,255,0),

                        Color.FromArgb(255,255,0),Color.FromArgb(255,0,0)};

IntensityColorMap cMap=new IntensityColorMap(values,colors);

Minimum and maximum values of the scale are required in more general case when the scale has the Auto-range property

// Change the color scale of the plot

intensityPlot1.ColorScale.LowColor=colors[0];

intensityPlot1.ColorScale.HighColor=colors[colors.Length-1];

intensityPlot1.ColorScale.ColorMap.Clear();

intensityPlot1.ColorScale.ColorMap.AddRange(cMap);

It is important to change the LowColor and HighColor of the ColorScale to the boundary colors of the new ColorMap, because it won't adjust them automatically

// Change the color map of the legend

intensityGraph1.ColorScales[0].LowColor=colors[0];

intensityGraph1.ColorScales[0].HighColor=colors[colors.Length-1];

intensityGraph1.ColorScales[0].ColorMap.Clear();

intensityGraph1.ColorScales[0].ColorMap.AddRange(cMap);

Following you tip I've done all changes on the ColorMap for the first element of the graph ColorScales array in order to adjust the graph legend as well. And finally

// Redraw the graph

intensityGraph1.Refresh();

This approach is working well. Thank you again for your help.

Sincerely,

Pavel