基本思想是,您希望使其看起来好像图形在可视区域内保持居中。我首先想到尝试扩展翻译点,也许这可能有效,但我无法让它发挥作用(3岁的孩子想读书并没有给我太多时间进行实验)。
基本上,您需要添加另一个平移,其中根据可视区域和缩放将 x/y 点移动适当的量,以便图像在可视区域内保持静止,然后在顶部应用缩放和法线平移其中...
double width = getWidth();
double height = getHeight();
double zoomWidth = width * zoom;
double zoomHeight = height * zoom;
double anchorx = (width - zoomWidth) / 2;
double anchory = (height - zoomHeight) / 2;
AffineTransform at = new AffineTransform();
at.translate(anchorx, anchory);
at.scale(zoom, zoom);
at.translate(-100, -100);
So, the anchorx/y
表示根据可视区域的宽度和高度,生成的图形需要偏移的量,以便图像保持在其中的“中心”...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseWheelEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.text.NumberFormat;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private double zoom = 1d;
private BufferedImage img;
public TestPane() {
try {
img = ImageIO.read(new File("..."));
} catch (IOException ex) {
ex.printStackTrace();
}
addMouseWheelListener(new MouseAdapter() {
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
if (e.getPreciseWheelRotation() < 0) {
zoom -= 0.1;
} else {
zoom += 0.1;
}
// zoom += e.getPreciseWheelRotation();
if (zoom < 0.01) {
zoom = 0.01;
}
repaint();
}
});
}
public String format(double value) {
return NumberFormat.getNumberInstance().format(value);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
double width = getWidth();
double height = getHeight();
double zoomWidth = width * zoom;
double zoomHeight = height * zoom;
double anchorx = (width - zoomWidth) / 2;
double anchory = (height - zoomHeight) / 2;
AffineTransform at = new AffineTransform();
at.translate(anchorx, anchory);
at.scale(zoom, zoom);
at.translate(-100, -100);
g2d.setTransform(at);
g2d.drawImage(img, 0, 0, this);
g2d.dispose();
}
}
}
可能有一个非常棒的数学公式你可以用它来代替,但我很笨;)