Question

I am trying to create a gradient fill for a series in an area chart that I am building through the BIRT chart API, but the book “Integrating and Extending BIRT” and the Interwebs seem curiously silent about how to get it to work. It seems no matter what I do, I always get a flat color from the default palette. I’ve tried using SeriesDefinition.getSeriesPalette().update(Gradient) and even creating my own Palette with the gradient fill in it and setting that on the SeriesDefinition, but to no avail. I’ve also noticed that if I do not perform a shift() on the Palette, even if it’s shift(0), which the Javadocs claim will do nothing, I get NullPointerException when I try to generate the chart:

Caused by: java.lang.NullPointerException
at org.eclipse.birt.chart.render.Area.renderDataPoints(Area.java:521)
at org.eclipse.birt.chart.render.Line.renderSeries(Line.java:570)
at org.eclipse.birt.chart.render.AxesRenderer.renderPlot(AxesRenderer.java:2181)
at org.eclipse.birt.chart.render.AxesRenderer.render(AxesRenderer.java:314)
at org.eclipse.birt.chart.factory.Generator.render(Generator.java:1368)
... 108 more

Here’s the latest (non-working) code that I’ve tried:

Gradient gradient = FillUtil.createDefaultGradient(BirtReportBuilder.COLOR_WHITE);
gradient.setStartColor(ColorDefinitionImpl.WHITE());
gradient.setEndColor(ColorDefinitionImpl.create(76, 116, 131));
gradient.setDirection(90);
SeriesDefinition sdY = SeriesDefinitionImpl.create();
sdY.getQuery().setDefinition("\"Quantity\"");
Palette pal = PaletteImpl.create(gradient);
pal.shift(0);
sdY.setSeriesPalette(pal);
sdY.getSeries().add(as1);
yAxisPrimary.getSeriesDefinitions().add(sdY);

So what’s the magic incantation to get the BIRT charting API to use my Gradient as the area fill?

Answer 1

This code works for me, I get a ugly coloured serie…

sdY.getSeriesPalette().update(GradientImpl.create(ColorDefinitionImpl.create(255,255,255), ColorDefinitionImpl.create(200,0,0,150), 90, false));

Hope it will help you ;p