Curved Line Charts

[tox0tes]

Is it possible to use curved lines in a line chart instead of jaggedness like so:

[RichardWest]

Is it possible to use curved lines in a line chart instead of jaggedness

Yes, use XYSplineRenderer.

[asd]

Hi

I instance an JFreeChart object
JFreeChart chart = ChartFactory.createLineChar(..);

so
chart.getPlot(); returns a CategoryPlot
chart.getXYPlot(); crash with: java.lang.ClassCastException: org.jfree.chart.plot.CategoryPlot cannot be cast to org.jfree.chart.plot.XYPlot

CategoryPlot.setRenderer( new XYSplineRenderer() ); will not work, so how can I use Splinerenderer?

I use version 1.0.9.

Thanks in advance

[RichardWest]

Try using ChartFactory.createXYLineChart(...) instead.

[tox0tes]

Code: Select all

import org.jfree.chart.renderer.xy.XYSplineRenderer;

I am getting

cannot find symbol
symbol : class XYSplineRenderer
location: package org.jfree.chart.renderer.xy

[RichardWest]

Code: Select all

import org.jfree.chart.renderer.xy.XYSplineRenderer;

I am getting

cannot find symbol
symbol : class XYSplineRenderer
location: package org.jfree.chart.renderer.xy

XYSplineRenderer has been available since v1.0.7 as stated in the JavaDoc, so you must be using v1.0.7 or later.

[tox0tes]

thanks, i upgraded to the correct version and now it works. How do I make the plot points smaller?

[RichardWest]

thanks, i upgraded to the correct version and now it works. How do I make the plot points smaller?

Extend XYSplineRenderer and override the getItemShape method inherited from AbstractRenderer.

[tox0tes]

thanks a lot, works great

[tox0tes]

almost.... there is a problem where the curve extends beyond the auto-range:

[RichardWest]

almost.... there is a problem where the curve extends beyond the auto-range:

The auto-range is best on the minimum and maximum values in the dataset plus some margin. The spline is not considered. The easiest solution would be to increase the lower margin, but feel free to contribute a patch if you figure out a more robust solution.