Is it possible to achieve transparent background in pie chart?

Hello. I’ve been trying to generate a piechart as an asset to my pdf template.

I need it to be png with transparent background but I’m only getting black solid colour instead.

Maybe I’m missing some property or doing something wrong with my colour settings.

Thanks!

Here is my code :

PieChart chart = new PieChartBuilder()
                .width(200)
                .height(200)
                .theme(Styler.ChartTheme.GGPlot2)
                .build();

        chart.getStyler().setLegendVisible(false);

        Color[] sliceColors = new Color[] {
                new Color(238, 88, 88), //red
                new Color(213, 122, 212), //purple
                new Color(106,230, 182), //mentol
                new Color(88,155,238) //baby blue
        };

        chart.getStyler().setSeriesColors(sliceColors);
        chart.getStyler().setChartTitleBoxVisible(false);
        chart.getStyler().setHasAnnotations(false);
        chart.getStyler().setChartBackgroundColor(
                new Color(255,255, 255, 0)
        );
        chart.getStyler().setPlotBackgroundColor(
                new Color(255,255, 255, 0)
        );
        chart.getStyler().setPlotBorderVisible(false);

        chart.addSeries("laptop", 65);
        chart.addSeries("pc", 10);
        chart.addSeries("tel", 12.5);
        chart.addSeries("winda", 12.5);

        BitmapEncoder.saveBitmap(chart, "./Sample_Chart", BitmapEncoder.BitmapFormat.PNG);

[timmolter]

I thought that the default background had an alpha of 1, which would mean necessitating manually setting to background alpha to 0 to get the desired transparency. If it’s now exporting with no transparency, then that would also be a bug in my opinion. In fact that might be why I set the type to TYPE_INT_RGB originally in:

new BufferedImage(chart.getWidth(), chart.getHeight(), BufferedImage.TYPE_INT_ARGB);

[Mr14huashao]

@staho @timmolter The code is updated. After the test, the background of the exported image is not black. You do not need to set alpha. This is not a color transparency issue, but a background issue for generating images.

    chart.getStyler().setChartBackgroundColor(new Color(255, 255, 255));
    chart.getStyler().setPlotBackgroundColor(new Color(255, 255, 255));