topic Re: How to use RenderingRule with Colormap to display imagery in greyscale in ArcGIS API for Silverlight Questions

How to use RenderingRule with Colormap to display imagery in greyscale

BobbyRadakovich — Thu, 10 Feb 2011 17:27:30 GMT

I am trying to apply a RenderingRule using a Colormap to switch my imagery display from color to greyscale (print preview for people without color printers). Here is my code snippet from the button handler that handles the switch:

[INDENT]        private void Button1_Click(object sender, RoutedEventArgs e)
        {
[INDENT]            ArcGISImageServiceLayer lyr = (ArcGISImageServiceLayer)(MyMap.Layers[0]);
            RenderingRule rule = new RenderingRule();
            rule.VariableName = "Raster";
            rule.RasterFunctionName = "Colormap";
            Dictionary<string, object> parms = new Dictionary<string, object>();
            parms.Add("ColormapName", "Gray");
            lyr.RenderingRule = rule;
            lyr.Refresh();
[/INDENT]        }
[/INDENT]
The code runs fine, but when the imagery layer refreshes instead of displaying in greyscale it just disappears altogether.

Ideas?

Re: How to use RenderingRule with Colormap to display imagery in greyscale

DominiqueBroux — Thu, 10 Feb 2011 18:35:38 GMT

Your dictionary of parameters looks initialized but never used.

Re: How to use RenderingRule with Colormap to display imagery in greyscale

ChristopherHill — Sat, 11 Dec 2021 08:11:02 GMT

private void Button1_Click(object sender, RoutedEventArgs e)
{
ArcGISImageServiceLayer lyr = (ArcGISImageServiceLayer)(MyMap.Layers[0]);


// Make sure when you are applying rendering rule that you are only 
// using a single color band id. Layer may have multiple color bands.
// You have to select a single color band id to convert to grayscale.

lry.BandIds = new int[] { bandID }; 
RenderingRule rule = new RenderingRule();
rule.VariableName = "Raster";
rule.RasterFunctionName = "Colormap";
Dictionary<string, object> parms = new Dictionary<string, object>();
parms.Add("ColormapName", "Gray");
rule.RasterFunctionArguments = parms; // Missing this line
lyr.RenderingRule = rule;
lyr.Refresh();
}