JPanelのJFrameのサイズに基づいて画像のサイズを動的に変更します

Dynamically Resize Image Based Size Jframe Jpanel

この方法は、JPanelの画像の左上隅の座標x、yを計算し、それに従って画像を描画することです。

import java.awt.* import java.awt.image.BufferedImage import java.io.* import javax.imageio.ImageIO import javax.swing.* public class AutoResize extends JPanel { BufferedImage image public AutoResize(BufferedImage image) { this.image = image } protected void paintComponent(Graphics g) { super.paintComponent(g) Graphics2D g2 = (Graphics2D)g g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC) int w = getWidth() int h = getHeight() int iw = image.getWidth() int ih = image.getHeight() double xScale = (double)w/iw double yScale = (double)h/ih double scale = Math.min(xScale, yScale) // scale to fit //Math.max(xScale, yScale) // scale to fill int width = (int)(scale*iw) int height = (int)(scale*ih) int x = (w - width)/2 int y = (h - height)/2 g2.drawImage(image, x, y, width, height, this) } public static void main(String[] args) throws IOException { String path = "images/bison.jpg" BufferedImage image = ImageIO.read(new File(path)) AutoResize test = new AutoResize(image) JFrame f = new JFrame() f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) f.add(test) f.setSize(400,400) f.setLocation(200,200) f.setVisible(true) } }