求助！！Swing 如何旋转所画的图形

FallinOut 2010-04-11 08:22:58
比如说用Graphics画了一个正方形在JPanel上，如何将该正方形任意角度旋转？？
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truediego 2010-04-12
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试试看吧





package to.shin.sai;



import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;



import javax.imageio.ImageIO;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;



public class Test4Rotate extends JFrame {

	private static final long serialVersionUID = 1L;



	public static void main(String[] args) {

		new Test4Rotate();

	}

	

	public Test4Rotate() {

		setSize(500, 300);

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		final MyPanel mp = new MyPanel();

		getContentPane().add(mp);

		

		mp.addMouseListener(new MouseAdapter() {

			

			@Override

			public void mousePressed(MouseEvent mouseevent) {

				int diagonal = (int)(50/Math.sin(Math.toRadians(45)));

				int x = 5 + (diagonal-50)/2;

				int y = 5 + (diagonal-50)/2;

				mp.bi = new BufferedImage(diagonal + 10 , diagonal + 10, BufferedImage.TRANSLUCENT);

				Graphics g = mp.bi.getGraphics();

				g.setColor(Color.red);

				g.drawLine(x, y, x+50, y);

				g.setColor(Color.blue);

				g.drawLine(x+50, y, x+50, y+50);

				g.setColor(Color.green);

				g.drawLine(x, y, x, y+50);

				g.setColor(Color.orange);

				g.drawLine(x, y+50, x+50, y+50);

				mp.repaint();

			}

		});

		

		JButton jb = new JButton();

		jb.setText("right 15°");

		jb.setSize(80, 20);

		jb.addActionListener(new ActionListener() {

			

			@Override

			public void actionPerformed(ActionEvent arg0) {

				mp.rotate = (mp.rotate + 15) % 360;

				mp.repaint();

			}

		});

		mp.add(jb);

		

		

		setVisible(true);

	}

	

	class MyPanel extends JPanel {

		private static final long serialVersionUID = 1L;

		private BufferedImage bi = null;

		private double rotate = 0;

		AffineTransform trans = null;

		private Image back = null;



		public MyPanel() {

			super();

			setOpaque(false);

			trans = new AffineTransform();

			try {

				back = ImageIO.read(new File("c:\\1.jpg"));

			} catch (IOException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

			}

		}



		@Override

		public void paintComponent(Graphics g) {

			g.drawImage(back, 0, 0, 500, 300, null);

			if (null != bi) {

				Graphics2D gg = (Graphics2D)g;

				trans.setToIdentity();

				trans.setToRotation(Math.toRadians(rotate), bi.getWidth()/2, bi.getHeight()/2);

				//gg.drawImage(back, trans, null);

				gg.drawImage(bi, trans, null);

			}

			super.paintComponent(g);

			

		}

		

	}



}
truediego 2010-04-12
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把正方形画在空image上，然后旋转image
b11ght 2010-04-12
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这个关注一下。
liujun3512159 2010-04-12
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学习一下
truediego 2010-04-12
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修正个bug



    private double calAngle(int x, int y, double A) {

        // 计算起始点象限

        int quadrant = 1;

        int tempY = 0;

        if (startX >= coorX && startY <= coorY)

            quadrant = 1;

        else if (startX < coorX && startY <= coorY)

            quadrant = 2;

        else if (startX < coorX && startY > coorY)

            quadrant = 3;

        else if (startX >= coorX && startY > coorY)

            quadrant = 4;



        tempY = (x - coorX) * (startY-coorY) / (startX-coorX) + coorY;

        switch (quadrant) {

        case 1:

        case 4:

            if (tempY > y)

                return -A;

            break;

        case 2:

        case 3:

            if (tempY < y)

                return -A;

            break;

        }

        return A;



    }
FallinOut 2010-04-12
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谢谢楼上各位，学习了
truediego 2010-04-12
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稍微升级了一下，鼠标点着旋转
可惜旋转之后会失真




package to.shin.sai;



import java.awt.BasicStroke;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;



import javax.imageio.ImageIO;

import javax.swing.ImageIcon;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;



public class Test4Rotate extends JFrame {

	private static final long serialVersionUID = 1L;

	int startX = -1;

	int startY = -1;

	int coorX = 0;

	int coorY = 0;



	public static void main(String[] args) {

		new Test4Rotate();

	}



	public Test4Rotate() {

		setSize(500, 300);

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		final MyPanel mp = new MyPanel();

		mp.setLayout(null);

		getContentPane().add(mp);



		int diagonal = (int) (100 / Math.sin(Math.toRadians(45)));

		int x = (diagonal - 100) / 2;

		int y = (diagonal - 100) / 2;

		BufferedImage bi = new BufferedImage(diagonal, diagonal, BufferedImage.TRANSLUCENT);

		Graphics g = bi.getGraphics();

		g.setColor(Color.red);

		g.drawLine(x, y, x + 100, y);

		g.setColor(Color.blue);

		g.drawLine(x + 100, y, x + 100, y + 100);

		g.setColor(Color.green);

		g.drawLine(x, y, x, y + 100);

		g.setColor(Color.orange);

		g.drawLine(x, y + 100, x + 100, y + 100);



		final MyLabel ml = new MyLabel(bi);

		ml.setBounds(50, 50, diagonal, diagonal);

		ml.addMouseListener(new MouseAdapter() {

			@Override

			public void mousePressed(MouseEvent mouseevent) {

				ml.dragging = true;

				startX = mouseevent.getX();

				startY = mouseevent.getY();

			}



			@Override

			public void mouseReleased(MouseEvent mouseevent) {

				ml.dragging = false;

				startX = -1;

				startY = -1;

				ml.img = ml.imgIcon;

				repaint();

				super.mouseReleased(mouseevent);

			}



		});

		ml.addMouseMotionListener(new MouseAdapter() {

			@Override

			public void mouseDragged(MouseEvent mouseevent) {

				if (ml.dragging) {

					// 根据余弦定理求得旋转角度

					int newPX = mouseevent.getX();

					int newPY = mouseevent.getY();



					double a2 = Math.pow(newPX - startX, 2) + Math.pow(newPY - startY, 2);

					double b2 = Math.pow(newPX - coorX, 2) + Math.pow(newPY - coorY, 2);

					double c2 = Math.pow(startX - coorX, 2) + Math.pow(startY - coorY, 2);

					// cosA=(b2+c2-a2)/2bc

					double A = Math.acos((b2 + c2 - a2) / (2 * Math.sqrt(b2) * Math.sqrt(c2)));

					ml.rotate(calAngle(newPX, newPY, A));

				}

				super.mouseMoved(mouseevent);

			}

		});

		mp.add(ml);



		coorX = ml.getWidth() / 2;

		coorY = ml.getHeight() / 2;



		setVisible(true);

	}



	/**

	 * 计算角度（正负）

	 * 

	 * @param x

	 * @param y

	 * @param A

	 * @return

	 */

	private double calAngle(int x, int y, double A) {

		// 计算起始点象限

		int quadrant = 1;

		int tempY = 0;

		if (startX >= coorX && startY <= coorY)

			quadrant = 1;

		else if (startX < coorX && startY <= coorY)

			quadrant = 2;

		else if (startX < coorX && startY > coorY)

			quadrant = 3;

		else if (startX >= coorX && startY > coorY)

			quadrant = 4;



		switch (quadrant) {

		case 1:

		case 4:

			tempY = x * startY / startX;

			if (tempY > y)

				return -A;

			break;

		case 2:

		case 3:

			tempY = x * startY / startX;

			if (tempY < y)

				return -A;

			break;

		}

		return A;



	}



	class MyPanel extends JPanel {

		private static final long serialVersionUID = 1L;

		private Image back = null;



		public MyPanel() {

			super();

			setOpaque(false);

			try {

				back = ImageIO.read(new File("c:\\1.jpg"));

			} catch (IOException e) {

				e.printStackTrace();

			}

		}



		@Override

		public void paintComponent(Graphics g) {

			g.drawImage(back, 0, 0, 500, 300, null);

			super.paintComponent(g);

		}



	}



	class MyLabel extends JLabel {

		private static final long serialVersionUID = 1L;

		private BufferedImage img = null;

		private BufferedImage imgIcon = null;

		AffineTransform trans = null;

		boolean dragging = false;



		public MyLabel(BufferedImage bi) {

			super(new ImageIcon(bi));

			setOpaque(false);

			trans = new AffineTransform();

			this.img = bi;

		}



		public void rotate(double rotate) {

			if (null != img) {

				imgIcon = new BufferedImage(img.getWidth(), img.getHeight(),

						BufferedImage.TRANSLUCENT);

				Graphics2D gg = (Graphics2D) imgIcon.getGraphics();

				trans.setToIdentity();

				trans.setToRotation(rotate, img.getWidth() / 2, img.getHeight() / 2);

				gg.drawImage(img, trans, null);

				setIcon(new ImageIcon(imgIcon));

			}

		}



		@Override

		public void paintComponent(Graphics g) {

			if (dragging) {

				//描绘旋转圆心

				Graphics2D gg = (Graphics2D) g;

				gg.setStroke(new BasicStroke(2));

				gg.setColor(Color.white);

				gg.drawOval(getWidth() / 2 - 2, getHeight() / 2 - 2, 4, 4);

			}

			super.paintComponent(g);

		}



	}



}
b11ght 2010-04-12
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[Quote=引用 6 楼 truediego 的回复:]
试试看吧


Java code


package to.shin.sai;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java……
[/Quote]
这个的确可以，帅啊。
FallinOut 2010-04-11
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[Quote=引用 1 楼 wd9053 的回复:]

你可以定义一个正方形类，
含正方形中心的x,y坐标，边长和旋转角度，然后绘图时计算各点的实际坐标
[/Quote]
这个我试过了，算出来的各点坐标都是double型的，转成int难免会有偏差，这样多旋转几次，正方形就变得扭曲了。。。
wd9053 2010-04-11
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你可以定义一个正方形类，
含正方形中心的x,y坐标，边长和旋转角度，然后绘图时计算各点的实际坐标
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