java更改图像的高度和宽度

Question

有一个宽450像素、高450像素的图像。我想把这个图像转换成75 x 75像素。我该怎么做

Answer 1

BufferedImage scaledImg = new BufferedImage(75, 75, BufferedImage.TYPE_INT_RGB);
scaledImg.createGraphics().drawImage(sourceImg, 0, 0, 75, 75, null);

Answer 2

从How to resize an image in Java?

public class ImageResize {

    private static final int IMG_WIDTH = 75;
    private static final int IMG_HEIGHT = 75;

    public static void main(String [] args){

    try{

        BufferedImage originalImage = ImageIO.read(new File("c:\\image\\img1.jpg"));
        int type = originalImage.getType() == 0? BufferedImage.TYPE_INT_ARGB : originalImage.getType();

        BufferedImage resizeImageJpg = resizeImage(originalImage, type);
        ImageIO.write(resizeImageJpg, "jpg", new File("c:\\image\\img1_jpg.jpg")); 

        BufferedImage resizeImagePng = resizeImage(originalImage, type);
        ImageIO.write(resizeImagePng, "png", new File("c:\\image\\img1_png.jpg")); 

        BufferedImage resizeImageHintJpg = resizeImageWithHint(originalImage, type);
        ImageIO.write(resizeImageHintJpg, "jpg", new File("c:\\image\\img1_hint_jpg.jpg")); 

        BufferedImage resizeImageHintPng = resizeImageWithHint(originalImage, type);
        ImageIO.write(resizeImageHintPng, "png", new File("c:\\image\\img1_hint_png.jpg")); 

    }catch(IOException e){
        System.out.println(e.getMessage());
    }

    }

    private static BufferedImage resizeImage(BufferedImage originalImage, int type){
    BufferedImage resizedImage = new BufferedImage(IMG_WIDTH, IMG_HEIGHT, type);
    Graphics2D g = resizedImage.createGraphics();
    g.drawImage(originalImage, 0, 0, IMG_WIDTH, IMG_HEIGHT, null);
    g.dispose();

    return resizedImage;
    }

    private static BufferedImage resizeImageWithHint(BufferedImage originalImage, int type){

    BufferedImage resizedImage = new BufferedImage(IMG_WIDTH, IMG_HEIGHT, type);
    Graphics2D g = resizedImage.createGraphics();
    g.drawImage(originalImage, 0, 0, IMG_WIDTH, IMG_HEIGHT, null);
    g.dispose();    
    g.setComposite(AlphaComposite.Src);

    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
    RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g.setRenderingHint(RenderingHints.KEY_RENDERING,
    RenderingHints.VALUE_RENDER_QUALITY);
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
    RenderingHints.VALUE_ANTIALIAS_ON);

    return resizedImage;
    }   
}