用过java2D的请进

[zhangpengju999]

遇到一问题：new 一个Line2D（）响应鼠标事件（鼠标进入图形时候图标形状变成十字状）的时候不能被选中，而new一个Rectangle（）或Ellipse（）可以被选中；这是为什么？如何将Line2D（）变为一个闭合图形，从而使之可选呢？谢谢！

[Dazzlingwinter]

呵呵，正在看Oreilly的java2D
给你一个例子，你看一下是如何选中的

import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Toolkit;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class ApplicationFrame extends Frame{
	/**
	 * 
	 */
	private static final long serialVersionUID = 5615364649875351782L;

	public ApplicationFrame() {
		this("ApplicationFrame v1.0");
	}
	
	public ApplicationFrame(String title) {
		super(title);
		createUI();
	}
	
	protected void createUI() {
		setSize(500, 400);
		center();
		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosed(WindowEvent e) {
				dispose();
				System.exit(0);
			}			
		});
	}
	
	public void center() {
		Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
		Dimension frameSize = getSize();
		int x = (screenSize.width - frameSize.width) / 2;
		int y = (screenSize.height - frameSize.height) / 2;
		setLocation(x, y);
	}
}

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.CubicCurve2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.QuadCurve2D;
import java.awt.geom.Rectangle2D;

public class DragKing extends ApplicationFrame implements MouseListener, MouseMotionListener{
	/**
	 * 
	 */
	private static final long serialVersionUID = -3997715010627598331L;
	protected Point2D[] mPoints;
	protected Point2D mSelectedPoint;
	
	public static void main(String[] args) {
		new DragKing();
	}
	
	public DragKing() {
		super("DragKing v1.0");
		setSize(300, 300);
		center();
		mPoints = new Point2D[9];
		//Cubic curve
		mPoints[0] = new Point2D.Double(50, 75);
		mPoints[1] = new Point2D.Double(100, 100);
		mPoints[2] = new Point2D.Double(200, 50);
		mPoints[3] = new Point2D.Double(250, 75);
		
		//Quad curve
		mPoints[4] = new Point2D.Double(50, 175);
		mPoints[5] = new Point2D.Double(150, 150);
		mPoints[6] = new Point2D.Double(250, 175);
		
		//Line
		mPoints[7] = new Point2D.Double(50, 275);
		mPoints[8] = new Point2D.Double(250, 275);
		mSelectedPoint = null;
		
		addMouseListener(this);
		addMouseMotionListener(this);
		
		setVisible(true);
	}
	
	@Override
	public void paint(Graphics g) {
		Graphics2D g2 = (Graphics2D)g;
		
		//Draw the tangents
		Line2D tangent1 = new Line2D.Double(mPoints[0], mPoints[1]);
		Line2D tangent2 = new Line2D.Double(mPoints[2], mPoints[3]);
		g2.setPaint(Color.gray);
		g2.draw(tangent1);
		g2.draw(tangent2);
		
		//Draw the cubic curve
		CubicCurve2D c = new CubicCurve2D.Float();
		c.setCurve(mPoints, 0);
		g2.setPaint(Color.black);
		g2.draw(c);
		
		//Draw the tangents
		tangent1 = new Line2D.Double(mPoints[4], mPoints[5]);
		tangent2 = new Line2D.Double(mPoints[5], mPoints[6]);
		g2.setPaint(Color.gray);
		g2.draw(tangent1);
		g2.draw(tangent2);
		
		//Draw the quadratic curve
		QuadCurve2D q = new QuadCurve2D.Float();
		q.setCurve(mPoints, 4);
		g2.setPaint(Color.black);
		g2.draw(q);
		
		//Draw the line
		Line2D l = new Line2D.Double();
		l.setLine(mPoints[7], mPoints[8]);
		g2.setPaint(Color.black);
		g2.draw(l);
		
		for(int i=0; i<mPoints.length; i++) {
			if(mPoints[i] == mSelectedPoint) {
				g2.setPaint(Color.red);
			}else {
				g2.setPaint(Color.blue);				
			}
			g2.fill(getControlPoint(mPoints[i]));
		}
		
	}

	protected Shape getControlPoint(Point2D p) {
		int side = 4;
		return new Rectangle2D.Double(p.getX() - side / 2, p.getY() -side / 2, side, side);
	}
	public void mouseDragged(MouseEvent e) {
		if(null != mSelectedPoint) {
			mSelectedPoint.setLocation(e.getPoint());
			repaint();
		}
		
	}

	public void mouseMoved(MouseEvent e) {
		
	}

	public void mouseClicked(MouseEvent e) {
		
	}

	public void mouseEntered(MouseEvent e) {
		
	}

	public void mouseExited(MouseEvent e) {
		
	}

	public void mousePressed(MouseEvent e) {
		mSelectedPoint = null;
		for(int i=0; i<mPoints.length; i++) {
			Shape s = getControlPoint(mPoints[i]);
			if(s.contains(e.getPoint())) {
				mSelectedPoint = mPoints[i];
				break;
			}
		}
		repaint();
	}

	public void mouseReleased(MouseEvent e) {
		
	}

}

[allysniper]

....很长

[zhangpengju999]

请问Dazzlingwinter，如何让鼠标在直线之上的时候变为十字状态，还有拖动的时候可整体移动呢；ps你的以上回复很有帮助~

[focusforce]

setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR))
貌似是这个

[Dazzlingwinter]

[Quote=引用 4 楼 focusforce 的回复:]
setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR))
貌似是这个
[/Quote]
LS修改鼠标形状的正解
当移出所属区域是应设置回原来形状
LZ，移动图形的我已经写好了，发你邮箱了，注意查收，就不贴在这里了，O(∩_∩)O~