I have a function in my java app that rotates an image by x degrees. Right now I pop up a simple JOptionPane that collects the rotation angle as a double from the us开发者_如何转开发er.
Is there a java widget that would allow the user to click / drag to a point on a circle to set the rotation angle visually?
Already checked out: AWT, SWT, Swing
Why not create one yourself? It should be fairly simple to do. Here is a quick draft i made in a few minutes... You can change it to your liking:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.MouseMotionListener;
import java.awt.geom.AffineTransform;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
* @author Savvas Dalkitsis
*/
public class Test {
public static void main(String[] args) {
JFrame f = new JFrame("Test");
final JRotation rot = new JRotation();
f.getContentPane().add(rot);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setVisible(true);
rot.addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseDragged(MouseEvent e) {
System.out.println(rot.getRotation());
}
});
}
}
@SuppressWarnings("serial")
class JRotation extends JPanel implements MouseMotionListener {
private double rotation = 1;
public double getRotation() {
return rotation;
}
public JRotation() {
setPreferredSize(new Dimension(100, 100));
addMouseMotionListener(this);
}
@Override
protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D)g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(Color.white);
g2.fillRect(0, 0, getWidth(), getHeight());
g2.setPaint(Color.black);
AffineTransform t = g2.getTransform();
g2.translate(getWidth()/2, getHeight()/2);
g2.rotate(-rotation);
g2.drawLine(0, 0, Math.max(getWidth(),getHeight()), 0);
g2.setTransform(t);
}
@Override
public void mouseDragged(MouseEvent e) {
int x = e.getX();
int y = e.getY();
int midX = getWidth() / 2;
int midY = getHeight() / 2;
if (x>midX) {
if (y>midY) { // fourth quadrant
rotation = 2*Math.PI - Math.atan((y-midY)/(double)(x-midX));
} else { // first quadrant
rotation = Math.atan((midY-y)/(double)(x-midX));
}
} else {
if (y>midY) { // third quarter
rotation = Math.PI + Math.atan((y-midY)/(double)(midX-x));
} else { // second quarter
rotation = Math.PI - Math.atan((midY-y)/(double)(midX-x));
}
}
repaint();
}
public void mouseMoved(MouseEvent e) {}
}
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