图片处理的三方工具

图片处理的三方工具

1.应用场景

对图片的操作，按比例缩放，固定尺寸缩放，按尺寸等比缩放，旋转，加水印，压缩图片质量，解决jdk原生对图片编码的兼容问题。

2.示例

2.1 jdk原生不支持的编码处理

public static void main(String[] args) throws Exception {
        InputStream in = new FileInputStream("D:\\11.jpg");
        System.out.println("输入数据量in="+in.available());
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[];
        while(true) {
            int offset = -1;
            try {
                offset = in.read(buffer);
            }catch(EOFException ex){
                ex.printStackTrace();
            }
            if(offset!=-1){
                baos.write(buffer, 0, offset);
            }else{
                break;
            }
        }
        baos.flush();
        InputStream stream1 = new ByteArrayInputStream(baos.toByteArray());
        BufferedImage bis = ImageIO.read(stream1);

    }

错误信息

输入数据量in=1250482
Exception in thread "main" javax.imageio.IIOException: Unsupported Image Type
	at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:1079)
	at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:1050)
	at javax.imageio.ImageIO.read(ImageIO.java:1448)
	at javax.imageio.ImageIO.read(ImageIO.java:1352)
	at com.example.demo.latitude.util.ImageUtil.main(ImageUtil.java:35)

Process finished with exit code 1

错误原因

javax.imageio.IIOException: Unsupported Image Type
一般是由于图片颜色模式是CMYK导致的，因为其内部读取文件的类JPEGImageReader只能读取RGB color mode，一般经过ps的图片自动保存曾jpeg格式颜色空间都会改变成CMYK，如果强行转换颜色空间会导致图片失色，gift的图色彩模式是CMYK模式（注意，这是给印刷机用的）在java.awt包下的Image类只能使用RGB模式。可以添加twelvemonkeys的jar即可解决报错，jdk的ImageIO有自动发现功能，会自动查找相关的编解码类并使用，而不使用jdk默认的编解码类，因此代码也不用修改，很方便。

需要的jar

        
        
            com.twelvemonkeys.imageio
            imageio-jpeg
            3.6
        
        
            com.twelvemonkeys.imageio
            imageio-tiff
            3.6
        
        
        
            com.twelvemonkeys.servlet
            servlet
            3.6
        
        

2.2 图片的快速处理工具

图片缩略图

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        Thumbnails.of(srcImagePath).size(200, 300).toFile(newImagePath);

指定比例缩略图

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        Thumbnails.of(srcImagePath).scale(0.9f).toFile(newImagePath);

对图片进行旋转

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        Thumbnails.of(srcImagePath).scale(1.0f).rotate(180).toFile(newImagePath);

对图片进行格式转换

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        Thumbnails.of(srcImagePath).scale(1.0f).outputFormat("jpg").toFile(newImagePath);

对图片进行剪裁

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        Thumbnails.of(srcImagePath).scale(1.0f).sourceRegion(Positions.CENTER, 400,      400).toFile(newImagePath);

对图片进行加水印操作

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        String warterImagePath = "C:\\Users\\23892\\Desktop\\3.png";
        Thumbnails.of(srcImagePath).scale(1.0f).watermark(Positions.CENTER, ImageIO.read(new File(warterImagePath)), 0.25f).toFile(newImagePath);

对图片进行加文字水印操作

        String newImagePath = "C:\\Users\\23892\\Desktop\\2.jpg";
        String srcImagePath = "C:\\Users\\23892\\Desktop\\2.png";
        BufferedImage bi = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = bi.createGraphics();
        g.setColor(Color.LIGHT_GRAY);
        g.drawRect(0, 0, 10, 10);
        char[] data = "lonsun".toCharArray();
        g.drawChars(data, 0, data.length, 5, 32);
        Thumbnails.of(srcImagePath).scale(1.0f).watermark(Positions.CENTER, bi, 1.0f).toFile(newImagePath);

需要的jar

        
            net.coobird
            thumbnailator
            0.4.8