Java operation pictures Daquan

foreword

This article mainly uses Java to process various operations on pictures.

1. Obtain the image format supported by the system

code:

System.out.println(Arrays.asList(ImageIO.getReaderFormatNames()));
System.out.println(Arrays.asList(ImageIO.getReaderFileSuffixes()));
System.out.println(Arrays.asList(ImageIO.getReaderMIMETypes()));

String[] writerFormatName = ImageIO.getWriterFormatNames();
String[] writerSuffixName = ImageIO.getWriterFileSuffixes();
String[] writerMIMEType = ImageIO.getWriterMIMETypes();

output:

[JPG, jpg, tiff, pcx, PCX, bmp, BMP, gif, GIF, WBMP, png, PNG, raw, RAW, JPEG, pnm, PNM, tif, TIF, TIFF, wbmp, jpeg]
[, jpg, tiff, pcx, bmp, gif, png, ppm, tif, pgm, wbmp, jpeg, pbm]
[, image/vnd.wap.wbmp, image/png, image/jpeg, image/x-portable-graymap, image/pcx, image/bmp, image/gif, image/x-windows-pcx, image/x-windows-bmp, image/x-pc-paintbrush, image/x-pcx, image/x-bmp, image/x-png, image/x-portable-bitmap, image/x-portable-pixmap, image/tiff, image/x-portable-anymap]

2. Generate custom pictures

code:

@SneakyThrows
public static void main(String[] args) {
    
    
    BufferedImage bufferedImage = new BufferedImage(400, 400, BufferedImage.TYPE_INT_BGR);
    Graphics g = bufferedImage.getGraphics();
    try {
    
    
        g.fillRect(20, 40, 400, 400);
        g.setColor(new Color(120, 120, 120));
        g.setFont(new Font("隶书", Font.BOLD, 28));
        g.drawString("自定义图片", 200, 200);
        ImageIO.write(bufferedImage, "jpg", new File("D:/test.jpg"));
    } finally {
    
    
        g.dispose();//释放画笔
    }
}

output:

3. Get the image format

code:

 public static String getImageFormatName(File file) throws IOException {
    
    
     String formatName = null;
     ImageInputStream iis = ImageIO.createImageInputStream(file);
     Iterator<ImageReader> imageReader = ImageIO.getImageReaders(iis);
     if (imageReader.hasNext()) {
    
    
         ImageReader reader = imageReader.next();
         formatName = reader.getFormatName();
     }
     return formatName;
 }

4. Image cropping

public static String cutImage(String sourcePath, String targetPath, int x, int y, int width, int height) throws IOException {
    
    
        File file = new File(sourcePath);
        if (!file.exists()) {
    
    
            throw new IOException("not found the image：" + sourcePath);
        }
        if (null == targetPath || targetPath.isEmpty()) {
    
    
            targetPath = sourcePath;
        }

        String formatName = getImageFormatName(file);
        if (null == formatName) {
    
    
            return targetPath;
        }
        formatName = formatName.toLowerCase();

        // 防止图片后缀与图片本身类型不一致的情况
        String pathPrefix = getPathWithoutSuffix(targetPath);
        targetPath = pathPrefix + formatName;

        // GIF需要特殊处理
        if (IMAGE_FORMAT.GIF.getValue() == formatName) {
    
    
            GifDecoder decoder = new GifDecoder();
            int status = decoder.read(sourcePath);
            if (status != GifDecoder.STATUS_OK) {
    
    
                throw new IOException("read image " + sourcePath + " error!");
            }

            AnimatedGifEncoder encoder = new AnimatedGifEncoder();
            encoder.start(targetPath);
            encoder.setRepeat(decoder.getLoopCount());
            for (int i = 0; i < decoder.getFrameCount(); i++) {
    
    
                encoder.setDelay(decoder.getDelay(i));
                BufferedImage childImage = decoder.getFrame(i);
                BufferedImage image = childImage.getSubimage(x, y, width, height);
                encoder.addFrame(image);
            }
            encoder.finish();
        } else {
    
    
            BufferedImage image = ImageIO.read(file);
            image = image.getSubimage(x, y, width, height);
            ImageIO.write(image, formatName, new File(targetPath));
        }
        return targetPath;
    }

5. Image compression

 public static String zoom(String sourcePath, String targetPath, int width, int height) throws IOException {
    
    
        File file = new File(sourcePath);
        if (!file.exists()) {
    
    
            throw new IOException("not found the image ：" + sourcePath);
        }
        if (null == targetPath || targetPath.isEmpty()) {
    
    
            targetPath = sourcePath;
        }
        String formatName = getImageFormatName(file);
        if (null == formatName) {
    
    
            return targetPath;
        }
        formatName = formatName.toLowerCase();
        String pathPrefix = getPathWithoutSuffix(targetPath);
        targetPath = pathPrefix + formatName;

        // GIF处理
        if (IMAGE_FORMAT.GIF.getValue() == formatName) {
    
    
            GifDecoder decoder = new GifDecoder();
            int status = decoder.read(sourcePath);
            if (status != GifDecoder.STATUS_OK) {
    
    
                throw new IOException("read image " + sourcePath + " error!");
            }
            AnimatedGifEncoder encoder = new AnimatedGifEncoder();
            encoder.start(targetPath);
            encoder.setRepeat(decoder.getLoopCount());
            for (int i = 0; i < decoder.getFrameCount(); i++) {
    
    
                encoder.setDelay(decoder.getDelay(i));
                BufferedImage image = zoom(decoder.getFrame(i), width, height);
                encoder.addFrame(image);
            }
            encoder.finish();
        } else {
    
    
            BufferedImage image = ImageIO.read(file);
            BufferedImage zoomImage = zoom(image, width, height);
            ImageIO.write(zoomImage, formatName, new File(targetPath));
        }
        return targetPath;
    }

6. Image watermark

  private static void waterMark(Image srcImg, String path) throws IOException {
    
    
        int srcImgWidth = srcImg.getWidth(null);
        int srcImgHeight = srcImg.getHeight(null);
/*
        //网络图片
        URL url = new URL("url");
        //将URL对象输入流转化为图片对象 (url.openStream()方法，获得一个输入流)
        Image srcImg = ImageIO.read(url.openStream());
        //获取图片的宽
        int srcImgWidth = srcImg.getWidth(null);
        //获取图片的高
        int srcImgHeight = srcImg.getHeight(null);
        System.out.println("图片的宽:"+srcImgWidth);
        System.out.println("图片的高:"+srcImgHeight);
*/
        BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight, BufferedImage.TYPE_INT_RGB);
        // 加水印
        //创建画笔
        Graphics2D g = bufImg.createGraphics();
        //绘制原始图片
        g.drawImage(srcImg, 0, 0, srcImgWidth, srcImgHeight, null);
/*
        //文字水印
        //根据图片的背景设置水印颜色
        g.setColor(new Color(255, 255, 255, 128));
        //设置字体  画笔字体样式为微软雅黑，加粗，文字大小为60pt
        g.setFont(new Font("微软雅黑", Font.BOLD, 60));
        String waterMarkContent = "自定义水印";
        //设置水印的坐标(为原图片中间位置)
        int x = srcImgWidth / 2;
        int y = srcImgHeight / 2;
        //画出水印 第一个参数是水印内容，第二个参数是x轴坐标，第三个参数是y轴坐标
        g.drawString(waterMarkContent, x, y);
        g.dispose();*/

        //图片水印
        // 水印文件
        String waterMarkImage = "D:/print.jpg";
        Image srcWaterMark = ImageIO.read(new File(waterMarkImage));
        //获取水印图片的宽度
        int widthWaterMark = srcWaterMark.getWidth(null);
        //获取水印图片的高度
        int heightWaterMark = srcWaterMark.getHeight(null);
        //设置 alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.9f));
        //绘制水印图片
        g.drawImage(srcWaterMark, (srcImgWidth - widthWaterMark) / 10,
                (srcImgHeight - heightWaterMark) / 10, widthWaterMark, heightWaterMark, null);
        // 水印文件结束
        g.dispose();

        //文件输出地址
        String tarImgPath = path;
        // 输出图片
        FileOutputStream outImgStream = new FileOutputStream(tarImgPath);
        ImageIO.write(bufImg, "png", outImgStream);
        outImgStream.flush();
        outImgStream.close();
    }

7. Thumbnails Tools

Through the above various operations on the picture, it is still necessary to convert the flow. Is there a tool that has already been formed? Yes, the Thumbnails tool class can handle the above situations.

There are mainly the following functional processing:

to rotate

watermark

cut out

Specify the size to zoom

Scale proportionally

Do not scale according to the specified size

Convert image format

Output to OutputStream

Output to BufferedImage

The code example is as follows:

rely

<dependency>
        <groupId>net.coobird</groupId>
        <artifactId>thumbnailator</artifactId>
        <version>0.4.17</version>
</dependency>

the code

 @SneakyThrows
    public static void main(String[] args) {
    
    
        //指定大小进行缩放
        Thumbnails.of("D:/test.jpg").size(100, 100).toFile("D:/test.jpg.jpg");

        //按照比例进行缩放
        // scale 图片的压缩比例 值在0-1之间，1f就是原图，0.5就是原图的一半大小
        // outputQuality 图片压缩的质量 值在0-1 之间，越接近1质量越好，越接近0 质量越差
        Thumbnails.of("D:/test.jpg").scale(0.75f).outputQuality(0.8f).toFile("D:/test.jpg");

        //不按照比例，指定大小进行缩放 100 keepAspectRatio(false) 默认是按照比例缩放的
        Thumbnails.of("D:/test.jpg").size(100, 100).keepAspectRatio(false).toFile("D:/test.jpg");

        //旋转  rotate(角度),正数：顺时针 负数：逆时针
        Thumbnails.of("D:/test.jpg").size(1024, 1024).rotate(90).toFile("C:/image+90.jpg");

        //水印 watermark(位置，水印图，透明度)
        Thumbnails.of("D:/test.jpg").size(1024, 1024)
                .watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("水印地址")), 0.5f)
                .outputQuality(0.4f).toFile("输出地址");

        //裁剪
        Thumbnails.of("D:/test.jpg").sourceRegion(Positions.CENTER, 400, 400).size(200, 200).keepAspectRatio(false)
                .toFile("输出地址");

        //转化图片格式
        Thumbnails.of("D:/test.jpg").size(666, 666).outputFormat("png").toFile("D:/test.png");

        // 输出到OutputStream
        OutputStream os = new FileOutputStream("D:/test.jpg");
        Thumbnails.of("test.jpg").size(666, 666).toOutputStream(os);

        //输出到BufferedImage
        BufferedImage thumbnail = Thumbnails.of("D:/test.jpg").size(666, 666).asBufferedImage();
        ImageIO.write(thumbnail, "jpg", new File("test.jpg"));
    }

Like, collect, follow
, those who know are not as good as those who are good