关于给图片添加水印

笔记

第一步 初始化

BufferedImage是Image的实现类，是一个带缓冲区图像类，主要作用是将一幅图片加载到内存中，提供获得绘图对象、图像缩放、选择图像平滑度等功能，通常用来做图片大小变换、图片变灰、设置透明不透明等。

/**
 * 初始化
 *
 * @param resourceImgPath
 * @param degree
 * @return
 * @throws IOException
 */
private static WaterMarkDto initGraphic(String resourceImgPath, Integer degree) throws IOException {
    Image srcImg = ImageIO.read(new File(resourceImgPath));
    // 创建图片对象
    BufferedImage buffImg = new BufferedImage(srcImg.getWidth(null), srcImg.getHeight(null), BufferedImage.TYPE_INT_RGB);
    // 基于图片对象打开绘图
    Graphics2D g = buffImg.createGraphics();
    // 消除画图锯齿
    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g.drawImage(srcImg.getScaledInstance(srcImg.getWidth(null), srcImg.getHeight(null), Image.SCALE_SMOOTH), 0, 0, null);
    // 旋转
    if (null != degree) {
        g.rotate(Math.toRadians(degree),
                (double) buffImg.getWidth() / 2,
                (double) buffImg
                        .getHeight() / 2);
    }
    return new WaterMarkDto().setGraphics(g).setResourceImage(srcImg).setBufferedImage(buffImg);
}

@Data
@Accessors(chain = true)
public class WaterMarkDto {

    private Graphics2D graphics;

    private Image resourceImage;

    private BufferedImage bufferedImage;
}

第二步 实现

/**
 * 给图片添加水印、可设置水印图片旋转角度
 *
 * @param iconPath        水印图片路径
 * @param resourceImgPath 源图片路径
 * @param targetPath      目标图片路径
 * @param degree          水印图片旋转角度
 */
public static void markImageByIcon(String iconPath, String resourceImgPath, String targetPath, Integer degree) {
    OutputStream os = null;
    try {
        if (StringUtils.isBlank(targetPath)) {
            targetPath = resourceImgPath.substring(0, resourceImgPath.lastIndexOf("."))
                    + FinalValue.WATER_MARK_IMG_POSTFIX + resourceImgPath.substring(resourceImgPath.lastIndexOf("."));
        }
        WaterMarkDto waterMarkDto = initGraphic(resourceImgPath, degree);
        Graphics2D graphics = waterMarkDto.getGraphics();
        ImageIcon imgIcon = new ImageIcon(iconPath);
        Image img = imgIcon.getImage();
        graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, FinalValue.WATER_MARK_TRANSPARENT));
        int width = waterMarkDto.getResourceImage().getWidth(null);
        int height = waterMarkDto.getResourceImage().getHeight(null);
        int iconWidth = img.getWidth(null);
        int iconHeight = img.getHeight(null);
        int x = (width - iconWidth)/2;
        int y = (height - iconHeight)/2;
        x = x < 0 ? 0 : x;
        y = y < 0 ? 0 : y;
        // 表示水印图片的位置
        graphics.drawImage(img, x, y, null);
        graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));
        graphics.dispose();
        os = new FileOutputStream(targetPath);
        ImageIO.write(waterMarkDto.getBufferedImage(), "JPG", os);
    } catch (Exception e) {
        log.error("生成图片水印失败:{}", e);
    } finally {
        try {
            if (null != os) {
                os.close();
            }
        } catch (Exception e) {
            log.error("关闭图片水印流失败:{}", e);
        }
    }
}

/**
 * 给图片添加水印文字、可设置水印文字的旋转角度
 *
 * @param logoText
 * @param resourceImgPath
 * @param targerPath
 * @param degree
 */
public static void markImageByText(String logoText, String resourceImgPath, String targerPath, Integer degree) {

    InputStream is = null;
    OutputStream os = null;
    try {
        if (StringUtils.isBlank(targerPath)) {
            targerPath = resourceImgPath.substring(0, resourceImgPath.lastIndexOf(".")) + FinalValue.WATER_MARK_IMG_POSTFIX + "f" + resourceImgPath.substring(resourceImgPath.lastIndexOf("."));
        }
        WaterMarkDto waterMarkDto = initGraphic(resourceImgPath, degree);
        Graphics2D graphics = waterMarkDto.getGraphics();
        graphics.setColor(Color.BLACK);
        graphics.setFont(FinalValue.WATER_MARK_FONT);
        graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, FinalValue.WATER_MARK_TRANSPARENT));
        graphics.drawString(logoText, FinalValue.WATER_MARK_POSITION_WIDTH, FinalValue.WATER_MARK_POSITION_HEIGHT);
        graphics.dispose();
        os = new FileOutputStream(targerPath);
        ImageIO.write(waterMarkDto.getBufferedImage(), "JPG", os);
    } catch (Exception e) {
        log.error("生成文字水印失败:{}", e);
        e.printStackTrace();
    } finally {
        try {
            if (null != is) {
                is.close();
            }
        } catch (Exception e) {
            log.error("关闭写入流失败:{}", e);
        }
        try {
            if (null != os) {
                os.close();
            }
        } catch (Exception e) {
            log.error("关闭输出流失败:{}", e);
        }
    }
}