java处理扩大与缩小图片

java处理扩大与缩小图片

图片扩大与缩小

在java.desktop.javax.imageio包下有操作图片相关的类。

不过，这些ImageIO只支持一些常见的图片类型:jpg,png等。

Java SE ImageIO docs

使用起来也不难：

    @Test
    public void testUp1() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.png");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        BufferedImage image = new BufferedImage(2000,1100 , bufferedImage.getType());
        Graphics2D graphics = image.createGraphics();
        graphics.drawImage(bufferedImage, 0,0,2000,1100,null);
        graphics.dispose();
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }

我准备的图片是一张1200*800的图片，jpg格式。

接着，我们转为2000*1100的图片，格式不变。

这是放大。

如果是缩小，就修改目标长度和宽度。比如800*400

想想，还能做其他的操作吗？

图片分层

比如双层？

    @Test
    public void testUp1() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.jpg");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        BufferedImage image = new BufferedImage(800,800 , bufferedImage.getType());
        Graphics2D graphics = image.createGraphics();
        graphics.drawImage(bufferedImage, 0,0,800,400,null);
        graphics.drawImage(bufferedImage, 0,400,800,400,null);
        graphics.dispose();
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }

图片灰度处理

在或者，图片变黑白？

依然是那张美女图。

    @Test
    public void testUp() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.jpg");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        ColorSpace space = ColorSpace.getInstance(ColorSpace.CS_GRAY);
        ColorConvertOp op = new ColorConvertOp(space, null);
        BufferedImage image = op.filter(bufferedImage, null);
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }

图片变绿色负片

说实话，我不太了解图像相关的知识，所以，如果名字不对，请包涵。

    @Test
    public void testUp() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.jpg");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        ColorSpace space = ColorSpace.getInstance(ColorSpace.CS_CIEXYZ);
        ColorConvertOp op = new ColorConvertOp(space, null);
        BufferedImage image = op.filter(bufferedImage, null);
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }

图片红化

    @Test
    public void testUp() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.jpg");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        ColorSpace space = ColorSpace.getInstance(ColorSpace.CS_PYCC);
        ColorConvertOp op = new ColorConvertOp(space, null);
        BufferedImage image = op.filter(bufferedImage, null);
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }

图片锐化

    @Test
    public void testUp() throws IOException {
    
    
        ClassPathResource classPathResource = new ClassPathResource("test.jpg");
        BufferedImage bufferedImage = ImageIO.read(classPathResource.getInputStream());
        ColorSpace space = ColorSpace.getInstance(ColorSpace.CS_LINEAR_RGB);
        ColorConvertOp op = new ColorConvertOp(space, null);
        BufferedImage image = op.filter(bufferedImage, null);
        OutputStream outputStream = new FileOutputStream("out.jpg");
        ImageIO.write(image, "jpg", outputStream);
        outputStream.flush();
        outputStream.close();
    }