附对比图：

合成后失真严重

代码优化后：

原代码：

参数解释：

1. img为你需要把他合成到A图片上的B图片，以下简称为章

2. srcImagePath为A图片的绝对路径

3. targetPath为合成后的图片输出路径

4. x,y为章需要合成到A图片上的位置坐标，w,h为将章缩小到多少长宽比例

注意这行代码：g.drawImage(img, x, y, w, h, null);

public static void markByIcon(Image img, String srcImagePath, String targetPath, int x, int y,int w, int h) throws IOException {OutputStream os = null;try {logger.info("图片水印开始添加。。。");logger.info("图片水印输入路径" + srcImagePath);logger.info("图片水印输出路径" + targetPath);Image srcImage = ImageIO.read(new File(srcImagePath));BufferedImage buffImg = new BufferedImage(srcImage.getWidth(null), srcImage.getHeight(null),BufferedImage.TYPE_INT_BGR);Graphics2D g = buffImg.createGraphics();g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);g.drawImage(srcImage.getScaledInstance(srcImage.getWidth(null), srcImage.getHeight(null), Image.SCALE_SMOOTH),0, 0, null);g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 1));g.drawImage(img, x, y, w, h, null);g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));g.dispose();os = new FileOutputStream(targetPath);//生成图片ImageIO.write(buffImg, "JPG", os);logger.info("图片水印添加成功。。。");} catch (Exception e) {logger.error("图片水印添加失败。。。", e);throw e;} finally {try {if (null != os) {os.close();}} catch (Exception e) {e.printStackTrace();}}}

优化后代码：

原代码是将章在合成的时候按比例缩小，在缩小过程中失真了，优化后为先将章缩小到想要的比例，然后用缩小后的章进行合成

压缩代码：

/*** * 将图片按照指定的图片尺寸压缩 * * @param srcImgPath :源图片路径 * @param outImgPath * :输出的压缩图片的路径 * @param new_w* * :压缩后的图片宽 * @param new_h * :压缩后的图片高*/public static BufferedImage compressImage(String srcImgPath, int new_w, int new_h) {BufferedImage src = inputImage(srcImgPath);BufferedImage bufferedImage = disposeImage(src, new_w, new_h);return bufferedImage;}/*** 处理图片 * * @param src * @param outImgPath * @param new_w * @param new_h*/private synchronized static BufferedImage disposeImage(BufferedImage src, int new_w, int new_h) {// 得到图片int old_w = src.getWidth();// 得到源图宽int old_h = src.getHeight();// 得到源图长BufferedImage newImg = null;// 判断输入图片的类型switch (src.getType()) {case 13:// png,gifnewImg = new BufferedImage(new_w, new_h,// BufferedImage.TYPE_4BYTE_ABGR);break;default:newImg = new BufferedImage(new_w, new_h, BufferedImage.TYPE_INT_RGB);break;}Graphics2D g = newImg.createGraphics();// 从原图上取颜色绘制新图g.drawImage(src, 0, 0, old_w, old_h, null);g.dispose();// 根据图片尺寸压缩比得到新图的尺寸newImg.getGraphics().drawImage(src.getScaledInstance(new_w, new_h, Image.SCALE_SMOOTH), 0, 0,null);// 调用方法输出图片文件return newImg;}/*** * 将图片文件输出到指定的路径，并可设定压缩质量 * * @param outImgPath * @param newImg * @param per*/private static void OutImage(String outImgPath, BufferedImage newImg) {// 判断输出的文件夹路径是否存在，不存在则创建File file = new File(outImgPath);if (!file.getParentFile().exists()) {file.getParentFile().mkdirs();}// 输出到文件流try {ImageIO.write(newImg, outImgPath.substring(outImgPath.lastIndexOf(".") + 1), new File(outImgPath));} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}

优化后代码：

先通过compressImage方法将章图片进行比例缩小，然后用缩小后的bufferedImage去进行合成

BufferedImage bufferedImage = ImageUtil.compressImage(signPath, photoConfig.getWidth(), photoConfig.getHeight());
Image signImg = ImageUtil.sign(bufferedImage);
if (signImg == null) {throw new MyException("图片生成失败,签名异常");
}
ImageUtil.markBySignIcon(signImg, imagePath, targetPath, x, y, photoConfig.getWidth(), photoConfig.getHeight());

此时我将原markByIcon方法进行了修改，修改后代码如下，修改后的方法名为markBySignIcon如上最后一行

public static void markBySignIcon(Image img, String srcImagePath, String targetPath, int x, int y,int w, int h) throws IOException {OutputStream os = null;try {logger.info("图片水印开始添加。。。");logger.info("图片水印输入路径" + srcImagePath);logger.info("图片水印输出路径" + targetPath);Image srcImage = ImageIO.read(new File(srcImagePath));BufferedImage buffImg = new BufferedImage(srcImage.getWidth(null), srcImage.getHeight(null),BufferedImage.TYPE_INT_BGR);Graphics2D g = buffImg.createGraphics();g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);g.drawImage(srcImage.getScaledInstance(srcImage.getWidth(null), srcImage.getHeight(null), Image.SCALE_SMOOTH),0, 0, null);g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 1));g.drawImage(img, x, y, img.getWidth(null), img.getHeight(null), null);g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));g.dispose();os = new FileOutputStream(targetPath);//生成图片ImageIO.write(buffImg, "JPG", os);logger.info("图片水印添加成功。。。");} catch (Exception e) {logger.error("图片水印添加失败。。。", e);throw e;} finally {try {if (null != os) {os.close();}} catch (Exception e) {e.printStackTrace();}}}

还记得之前标红，要注意的代码么，现在改成如下

g.drawImage(img, x, y, img.getWidth(null), img.getHeight(null), null);

到此，用来合成的小图章在合成后，效果会较原来好很多