在java中调整jpeg图像的大小

Question

我正在研究java中的图像比较。我认为在比较图像之前，最好处理图像以设置固定大小的图像。是否有任何java功能来调整图像大小。我想将图像重新缩放到300 * 225。

Answer 1

BufferedImage img = ImageIO.read(imageFile);
Image scaled = img.getScaledInstance(300, 255, Image.SCALE_DEFAULT);

您还可以查看java-image-scaling库。

Answer 2

BufferedImage createResizedCopy(Image originalImage, 
                int scaledWidth, int scaledHeight, 
                boolean preserveAlpha)
{
    int imageType = preserveAlpha ? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
    BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight, imageType);
    Graphics2D g = scaledBI.createGraphics();
    if (preserveAlpha) {
            g.setComposite(AlphaComposite.Src);
    }
    g.drawImage(originalImage, 0, 0, scaledWidth, scaledHeight, null); 
    g.dispose();
    return scaledBI;
}  

• This threads answers your question well

• Very interesting article on manipulating images

Answer 3

public ImageIcon resizeImage(String filePath, int w, int h) {


        String data = filePath;
        BufferedImage bsrc, bdest;
        ImageIcon theIcon;

//scale the image
        try
        {

            bsrc = ImageIO.read(new File(data));

            bdest = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bdest.createGraphics();
            AffineTransform at = AffineTransform.getScaleInstance((double) w / bsrc.getWidth(),
                    (double) h / bsrc.getHeight());
            g.drawRenderedImage(bsrc, at);

            //add the scaled image
            theIcon = new ImageIcon(bdest);
            return theIcon;
        }
        catch (Exception e)
        {
            System.out.println("This image can not be resized. Please check the path and type of file.");
            return null;
        }

     }