透明背景PNG - Java的 - BufferedImage

Question

我想從一個透明的而不是白色背景的Java顯示圖像創建一個PNG。嘗試將新顏色（0,0,0,0）中的alpha設置爲0 - 背景顯示爲白色仍然是？

我使用的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

你是不是在指定的顏色模式的alpha分量。試試這種方式：

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());