我正在编写一个程序，它应该允许用户创建房间的平面图 - 这意味着他们可以画线来表示墙壁等。我正在使用带有 Graphics 2D 的 JPanel 来完成所有绘图工作，目前我有一个网格设置为 JPanel 的背景，我可以根据鼠标移动绘制线条（我有一个具有两种状态的鼠标状态枚举 - 拖动和空闲）。但是，我想向线条添加控制点，以便在绘制它们后可以在 JPanel 周围移动它们，但我不知道如何做到这一点。我知道我需要矩形来表示点，但我不知道如何将它们链接到线，以便如果点移动，线也会移动。我将不胜感激。
这是 JPanel 类的代码：
package floorplan;
/**
*
* @author xodkx
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.BufferedImage;
import java.awt.event.MouseListener;
public class Floor extends JPanel implements MouseListener, MouseMotionListener
{
private static final int WIDTH = Integer.parseInt(JOptionPane.showInputDialog("Please
enter the width of your room"));
private static final int LENGTH = Integer.parseInt(JOptionPane.showInputDialog("Please
enter the width of your room"));
private static final Color BACKGROUND = Color.WHITE;
private static final Color INITIAL_COLOUR = Color.BLACK;
private static final Framework INITIAL_FRAMEWORK = Framework.WALL;
private MouseState state = MouseState.IDLE;
private Framework frameworkType = INITIAL_FRAMEWORK;
private Color colour = INITIAL_COLOUR;
private Point start = null;
private Point end = null;
private Rectangle startpt = new Rectangle(0, 0, 8, 8);// Start control point
private Rectangle endpt = new Rectangle(0, 0, 8, 8);// End control point
private BufferedImage bufImage = null;
public Floor()
{
setPreferredSize(new Dimension(LENGTH,WIDTH));
setBackground(Color.white);
setBorder(BorderFactory.createLineBorder (Color.black, 5));
this.addMouseListener(this);
this.addMouseMotionListener(this);
}
public void setColor(Color color)
{
colour = color;
}
public void setFramework(Framework framework)
{
frameworkType = framework;
}
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
if(bufImage == null)
{
int h = this.getHeight();
int w = this.getWidth();
bufImage = (BufferedImage)this.createImage(h,w);
Graphics2D gc = bufImage.createGraphics();
gc.setColor(BACKGROUND);
gc.fillRect(0, 0, w, h);
}
g2.drawImage(bufImage,null,0,0);
drawGrid(g2);
if(state == MouseState.DRAGGING)
{
createComponent(g2);
}
}
public void drawGrid(Graphics g2)// sets a grid as the background of the JPanel
{
int gridDivisions = 20;
int divisionSize = WIDTH/gridDivisions;
int grid = WIDTH*LENGTH;
g2.setColor(Color.lightGray);
for(int i=1; i<grid; i++)
{
int x = i * divisionSize;
g2.drawLine(x,0,x,getSize().height);
}
for(int i=1; i<grid; i++)
{
int y = i*divisionSize;
g2.drawLine(0,y,getSize().width,y);
}
}
public void createComponent(Graphics2D g2)// method that draws the lines for various
components of the room
{
g2.setColor(colour);
switch (frameworkType)
{
case WALL:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
case DOOR:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
case WINDOW:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
default:
g2.drawString("test", 10, 20);
break;
}
}
@Override
public void mousePressed(MouseEvent e)
{
state = MouseState.DRAGGING;
start = e.getPoint();
end = start;
}
@Override
public void mouseDragged(MouseEvent e)
{
state = MouseState.DRAGGING;
end = e.getPoint();
this.repaint();
}
@Override
public void mouseReleased(MouseEvent e)
{
end = e.getPoint();
if(state == MouseState.DRAGGING)
{
state = MouseState.IDLE;
createComponent(bufImage.createGraphics());
this.repaint();
}
}
@Override
public void mouseClicked(MouseEvent e)
{
}
@Override
public void mouseEntered(MouseEvent e)
{
}
@Override
public void mouseExited(MouseEvent e)
{
}
@Override
public void mouseMoved(MouseEvent e)
{
}
}