透明背景png-Java-BufferedImage

Question

I'm trying to have a png created from an image in Java display with a transparent instead of white background. Tried setting alpha to 0 in new Color(0,0,0,0) - background appears white still ?

I am using BufferedImage

WritableRaster raster = onscreenImage.getRaster();
            WritableRaster newRaster;
            newRaster = raster.createWritableChild(0, 0, width, height, 0, 0, new int[] {0, 1, 2});
            DirectColorModel cm = (DirectColorModel) onscreenImage.getColorModel();
            DirectColorModel newCM = new DirectColorModel(cm.getPixelSize(),
                                                          cm.getRedMask(),
                                                          cm.getGreenMask(),
                                                          cm.getBlueMask());
            BufferedImage rgbBuffer = new BufferedImage(newCM, newRaster, false,  null);
            try { ImageIO.write(rgbBuffer, suffix, file); }
            catch (IOException e) { e.printStackTrace(); }

Answer 1

You aren't specifying the alpha component in the color model. Try in this way:

newRaster = raster.createWritableChild(0, 0, width, height, 0, 0, null);
DirectColorModel cm = (DirectColorModel) onscreenImage.getColorModel();
DirectColorModel newCM = new DirectColorModel(cm.getPixelSize(),
                                                      cm.getRedMask(),
                                                      cm.getGreenMask(),
                                                      cm.getBlueMask(),
                                                      cm.getAlphaMask());