--sunfruit
設置圖片的每個象素Alpha，使得圖片透明，核心代碼如下
private void setAlpha(ByteArrayOutputStream os) {
/**
* 增加測試項
* 讀取圖片，繪制成半透明
*/
try {
ImageIcon imageIcon = new ImageIcon(os.toByteArray());
BufferedImage bufferedImage = new BufferedImage(imageIcon.getIconWidth(),imageIcon.getIconHeight()
, BufferedImage.TYPE_4BYTE_ABGR);
Graphics2D g2D = (Graphics2D) bufferedImage.getGraphics();
g2D.drawImage(imageIcon.getImage(), 0, 0,
imageIcon.getImageObserver());
//循環每一個像素點，改變像素點的Alpha值
int alpha = 100;
for (int j1 = bufferedImage.getMinY(); j1 < bufferedImage.getHeight(); j1++) {
for (int j2 = bufferedImage.getMinX(); j2 < bufferedImage.getWidth(); j2++) {
int rgb = bufferedImage.getRGB(j2, j1);
rgb = ( (alpha + 1) << 24) | (rgb & 0x00ffffff);
bufferedImage.setRGB(j2, j1, rgb);
}
}
g2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());
//生成圖片為PNG
ImageIO.write(bufferedImage, "png", new File(圖片路徑));
}
catch (Exception e) {
e.printStackTrace();
}
}