Setting Chart Series Palette to use a gradient

jmangan

Is there a way to set a start and end color for a chart (say a pie chart), and have BIRT count the number of slices at run time and calculate a gradient for the slices and apply the colors to the Series Palette?

JasonW

Yes this is possible. Individual bars/slices support gradients, but you want the entire pie chart to act like a gradient I assume. There are a couple of ways to do this but the easiest is to just use a little script like:

piecnt = 0;
startColor = null;
endColor = null;
importPackage( Packages.org.eclipse.birt.chart.model.attribute.impl );

function afterDataSetFilled(series, dataSet, icsc)
{
importPackage( Packages.java.io );
importPackage( Packages.org.eclipse.birt.chart.model.type.impl );

if( series.getClass() == PieSeriesImpl ){
if( series.getSeriesIdentifier() == "mypie" ){
var list = dataSet.getValues();
piecnt = list.length;
}


}
startColor = ColorDefinitionImpl.RED();
endColor = ColorDefinitionImpl.ORANGE();
//startColor = ColorDefinitionImpl.GREY();
//endColor = ColorDefinitionImpl.BLACK();

}
function buildPalette( sliceNumber )
{
var sr = startColor.getRed();
var sg = startColor.getGreen();
var sb = startColor.getBlue();

var er = endColor.getRed();
var eg = endColor.getGreen();
var eb = endColor.getBlue();

var nr = ((er-sr)/piecnt)*sliceNumber + sr;
var ng = ((eg-sg)/piecnt)*sliceNumber + sg;
var nb = ((eb-sb)/piecnt)*sliceNumber + sb;

var nc = ColorDefinitionImpl.create( nr, ng, nb );
return nc;


}

function beforeGeneration( chart, icsc )
{
sd = chart.getSeriesDefinitions( ).get( 0 );
sd.getSeriesPalette( ).getEntries( ).clear( );

for ( i = 1; i <= piecnt; i++ )
{
sd.getSeriesPalette().getEntries().add( buildPalette(i) );
}
}

In this example I used red to orange. Sample report and picture attached