解決Java處理圖像時可能變紅、變色問題

解決Java處理圖像時可能變紅、變色問題

...省略上下文代碼
URL url = new URL(url);

/* Java上傳圖片時，對某些圖片進行縮放、裁剪或者生成縮略圖時會蒙上一層紅色，實際使用中發現有部分圖片會蒙上一層紅色的蒙層，
	因此通過Toolkit創建圖片，然後轉成BufferedImage的類型來解決這個問題。 */
Image imageToolkitTitle = Toolkit.getDefaultToolkit().createImage(url);
BufferedImage image = this.toBufferedImage(imageToolkitTitle);
...

/**
 * 將圖片轉成BufferedImage格式
 *
 * @author SevenWong
 * @date 2020-04-30 15:30:00
 **/
private BufferedImage toBufferedImage(Image image) {
	if (image instanceof BufferedImage) {
		return (BufferedImage) image;
	}
	// This code ensures that all the pixels in the image are loaded
	image = new ImageIcon(image).getImage();
	BufferedImage bimage = null;
	GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
	try {
		int transparency = Transparency.OPAQUE;
		GraphicsDevice gs = ge.getDefaultScreenDevice();
		GraphicsConfiguration gc = gs.getDefaultConfiguration();
		bimage = gc.createCompatibleImage(image.getWidth(null),
				image.getHeight(null), transparency);
	} catch (HeadlessException e) {
		// The system does not have a screen
	}
	if (bimage == null) {
		// Create a buffered image using the default color model
		int type = BufferedImage.TYPE_INT_RGB;
		bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
	}
	// Copy image to buffered image
	Graphics2D g = bimage.createGraphics();

	// 增加透明度解決png透明圖片會變黑的問題
	bimage = g.getDeviceConfiguration().createCompatibleImage(image.getWidth(null), image.getHeight(null), Transparency.TRANSLUCENT);
	g = bimage.createGraphics();

	// Paint the image onto the buffered image
	g.drawImage(image, 0, 0, null);
	g.dispose();
	return bimage;
}