java - 如何调整图像大小和旋转图像

Question

我想旋转图像，在下一个级别我想调整它的大小，请帮我。我创建一个从 JPanel 扩展的类并重写 PaintComponent() 方法用于绘制图像。

public class NewJPanel extends javax.swing.JPanel {

/** Creates new form NewJPanel */
public NewJPanel() {
    initComponents();
}

@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.drawImage(image, 20, 20, this);
}

Answer 1

这是我使用的一些代码。您可以修改它以满足您的需要。

调整图像大小:

/**
 * Resizes the image
 *
 * @param filePath File path to the image to resize
 * @param w        Width of the image
 * @param h        Height of the image
 * @return A resized image
 */
public ImageIcon resizeImage(String filePath, int w, int h) {
    String data = filePath;
    BufferedImage bsrc, bdest;
    ImageIcon theIcon;
    //scale the image
    try {
        if (dataSource == DataTypeEnum.file) {
            bsrc = ImageIO.read(new File(data));
        } else {
            bsrc = ImageIO.read(new URL(filePath));
        }
        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) {
        Window.getLogger().warning("This image can not be resized. " +
                "Please check the path and type of file.");
        //restore the old background
        return null;
    }
}

旋转图像:
注意:角度以弧度为单位

public static BufferedImage rotate(BufferedImage image, double angle) {
    double sin = Math.abs(Math.sin(angle)),
           cos = Math.abs(Math.cos(angle));
    int w = image.getWidth(),
        h = image.getHeight();
    int neww = (int) Math.floor(w * cos + h * sin),
        newh = (int) Math.floor(h * cos + w * sin);
    GraphicsConfiguration gc = getDefaultConfiguration();
    BufferedImage result =
            gc.createCompatibleImage(neww, newh, Transparency.TRANSLUCENT);
    Graphics2D g = result.createGraphics();
    g.translate((neww - w) / 2, (newh - h) / 2);
    g.rotate(angle, w / 2, h / 2);
    g.drawRenderedImage(image, null);
    g.dispose();
    return result;
}