How to Autopaint a Chart Series

Let's assume we use a Datasource and a Series Splitter when creating a Chart. This means that the number of Series to be displayed cannot be defined beforehand. Different Series are colored according to the specified Palette preset, but you can run into the situation when the number of Palette presets is limited.
In this example we will demonstrate how the undefined number of different Series could be painted with various color combinations.

To do this, you should execute the following code at report or Chart control loading:


 

//Getting ChartArea
 
ChartArea chartArea = chart.GetByName("ChartArea1") as ChartArea;
 
//Creating a CustomPalette to which we can add colors manually
//Initially it's empty
CustomPalette palette = new CustomPalette();
 
//Setting a new chartArea palette
chartArea.Palette = palette;
 
//Getting all Series from ChartArea
Series[] series = chartArea.GetSeries();
int numberOfColors = series.Length;
 
for (int i = 0; i < numberOfColors; i++)
{
 
  //With the help of HSV system we can get an equidistant hue
Color nextColor = ColorFromHSV((int)(360.0 * i / numberOfColors), 1, 1);
 
//Creating Item palettes
   CustomPaletteItem item = new CustomPaletteItem();
 
//Setting a fill and a stroke for a palette
   item.Fill = new SolidFill(nextColor);
   item.Stroke = new SimpleStroke(LineStyle.Solid, nextColor, 5);
//Adding an element to palette
   palette.Items.Add(item);
}

 

Follow the link to download a sample:http://perpetuumsoft.com/Support/M1/ChartAutoColoringReportSample2010.zip





For more information on HSV system, please refer to http://en.wikipedia.org/wiki/HSL_and_HSV


Conversion of HSV to RGB Color:

 

/// Convert HSV to RGB
       /// h is from 0-360
       /// s,v values are 0-1
       /// r,g,b values are 0-255
       public static Color ColorFromHSV(double hue, double saturation, double value)
       {
           int hi = Convert.ToInt32(Math.Floor(hue / 60)) % 6;
           double f = hue / 60 - Math.Floor(hue / 60);
 
           value = value * 255;
           int v = Convert.ToInt32(value);
           int p = Convert.ToInt32(value * (1 - saturation));
           int q = Convert.ToInt32(value * (1 - f * saturation));
           int t = Convert.ToInt32(value * (1 - (1 - f) * saturation));
 
           if (hi == 0)
               return Color.FromArgb(255, v, t, p);
           else if (hi == 1)
               return Color.FromArgb(255, q, v, p);
           else if (hi == 2)
               return Color.FromArgb(255, p, v, t);
           else if (hi == 3)
               return Color.FromArgb(255, p, q, v);
           else if (hi == 4)
               return Color.FromArgb(255, t, p, v);
           else
               return Color.FromArgb(255, v, p, q);
       }