How to save current chart in ChartPanel as PNG programmatically?

Question

I have created a JFreeChart in a ChartPanel and I want to save it programmatically. The functionality should exist as it is possible to do this manually (right click menu and PNG option from there).

I found the method chartPanel.createImage(??, ??), but I don't know what width and height I need to set.

score 10 · Accepted Answer · answered Jan 17 '16 at 08:13

10

The solution was to use a method ChartUtilities.writeChartAsPNG

Example:

try {

    OutputStream out = new FileOutputStream(chartName);
    ChartUtilities.writeChartAsPNG(out,
            aJFreeChart,
            aChartPanel.getWidth(),
            aChartPanel.getHeight());

} catch (IOException ex) {
    logger.error(ex);
}

answered Jan 17 '16 at 08:13

zygimantus

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3

Why not one of the `ChartUtilities.saveChartAsPNG()` variations? – trashgod Jan 17 '16 at 11:25
3

At the version 1.5.0 the classe ChartUtilities changed to org.jfree.chart.ChartUtils; – Jadson Santos Jan 09 '19 at 13:48

score 2 · Answer 2 · answered Jan 26 '18 at 14:39

Also, you can do this:

public static void exportAsPNG throws IOException {
    JFreeChart chart = createChart(createDataset());


    BufferedImage image = new BufferedImage(600, 400, BufferedImage.TYPE_INT_ARGB);
    Graphics2D g2 = image.createGraphics();

    g2.setRenderingHint(JFreeChart.KEY_SUPPRESS_SHADOW_GENERATION, true);
    Rectangle r = new Rectangle(0, 0, 600, 400);
    chart.draw(g2, r);
    File f = new File("/tmp/PNGTimeSeriesChartDemo1.png");



    BufferedImage chartImage = chart.createBufferedImage( 600, 400, null); 
    ImageIO.write( chartImage, "png", f ); 
}

Could you explain what is the advantage of your answer over the accepted, embedded one? — Line, Feb 18 '19 at 16:03

score 2 · Answer 3 · answered Nov 06 '20 at 20:07

Prior to version 1.5 use ChartUtilities class

ChartUtilities.saveChartAsPNG(<File>, chart, width, height);
ChartUtilities.writeChartAsPNG(<OutputStream>, chart, width, height);

With version 1.5 JFreeChart renamed ChartUtilities class to ChartUtils. It offers the same functionality.

ChartUtils.saveChartAsPNG(<File>, chart, width, height);
ChartUtils.writeChartAsPNG(<OutputStream>, chart, width, height);

Please note that there are more variants of those methods.

How to save current chart in ChartPanel as PNG programmatically?

3 Answers3