drawcurve.java

在Java中使用Draw2D和SWT绘图

import java.awt.*; 

import java.awt.event.*; 

import javax.swing.*; 

import java.awt.geom.*; 



public class DrawCurve extends JFrame 

{ 

public JPanel contentPane; //绘图窗口 



JPanel jPanel1 = new JPanel();//控件容器 

JButton jButton1 = new JButton(); 

JButton jButton2 = new JButton(); 

JButton jButton3 = new JButton(); 





GraphicsCurve gracu; 





//构造函数 

public DrawCurve() { 

enableEvents(AWTEvent.WINDOW_EVENT_MASK); 

try { 

jbInit(); 

} 

catch(Exception e) { 

e.printStackTrace(); 

} 

} 



//控件初始化 



private void jbInit() throws Exception { 

contentPane = (JPanel) this.getContentPane(); 

contentPane.setLayout(new BorderLayout()); 

this.setSize(new Dimension(500,400)); 

this.setTitle("Frame Title"); 

//contentPane.setSize(400,240); 

jPanel1.setLayout(null); 

jButton1.setBounds(new Rectangle(30, 310, 100, 31)); 

jButton1.setText("直线"); 





jButton1.addActionListener(new java.awt.event.ActionListener() { 

public void actionPerformed(ActionEvent e) { 

jButton1_actionPerformed(e); 

} 

}); 





jButton2.setBounds(new Rectangle(150, 310, 100, 30)); 

jButton2.setText("样条曲线"); 



jButton2.addActionListener(new java.awt.event.ActionListener() { 

public void actionPerformed(ActionEvent e) { 

jButton2_actionPerformed(e); 

} 

}); 



jButton3.setBounds(new Rectangle(270, 310, 100, 30)); 

jButton3.setText("粗线条"); 



jButton3.addActionListener(new java.awt.event.ActionListener() { 

public void actionPerformed(ActionEvent e) { 

jButton3_actionPerformed(e); 

} 

}); 



contentPane.add(jPanel1, BorderLayout.CENTER); 

jPanel1.add(jButton1, null); 

jPanel1.add(jButton2, null); 

jPanel1.add(jButton3, null); 



gracu=new GraphicsCurve(); 

} 



public static void main(String[] args) { 



DrawCurve frame=new DrawCurve(); 

frame.show(); 

frame.gracu.myGraphics=(Graphics2D)frame.contentPane .getGraphics(); 

frame.gracu.myGraphics.setBackground(Color.white); 

frame.gracu.myGraphics.clearRect(0,0,500,300); 

} 



//Overridden so we can exit when window is closed 

protected void processWindowEvent(WindowEvent e) { 

super.processWindowEvent(e); 

if (e.getID() == WindowEvent.WINDOW_CLOSING) { 

System.exit(0); 

} 

} 

int Xs1[]={10,60,120,200,260,340}; 

int Ys1[]={10,200,120,180,60,130}; 



//画折线 

void jButton1_actionPerformed(ActionEvent e){ 



gracu.myGraphics.setPaint(Color.blue); 

gracu.myGraphics.drawPolyline(Xs1,Ys1,Xs1.length); 

} 



//画样条 

void jButton2_actionPerformed(ActionEvent e) { 



gracu.myGraphics.setPaint(Color.red); 

gracu.DrawCurves(Xs1,Ys1); 

} 



//画粗线 

void jButton3_actionPerformed(ActionEvent e) { 

//笔宽度 

float thick = 10f; 

//设置笔刷 

//方头园连接 

//gracu.myGraphics.setStroke(new BasicStroke(thick, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND)); 

//园头园连接 

gracu.myGraphics.setStroke(new BasicStroke(thick, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND)); 

gracu.myGraphics.setPaint(Color.blue); 

//通过该方法使图形去除锯齿状 

gracu.myGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 

RenderingHints.VALUE_ANTIALIAS_ON); 

gracu.myGraphics.drawPolyline(Xs1,Ys1,Xs1.length); 

} 

} 



class GraphicsCurve 

{ 

//绘图对象 

public Graphics2D myGraphics; 



public GraphicsCurve() 

{ 



} 



public GraphicsCurve(Graphics2D graphics) 

{ 

this.myGraphics=graphics; 

} 

//参数表 

//x数组，y数组，笔刷 

public void DrawCurves(int[] xa,int[] ya) 

{ 



int[] x, y; 

double[] a, b, c; 

double[] px, py, qx, qy, tt; 

double[] dx, dy; 

int px1,py1,px2,py2; 

x=xa; 

y=ya; 

px1=x[0]; 

py1=y[0]; 

int n=x.length; 

a=new double[n]; 

b=new double[n]; 

c=new double[n]; 

px=new double[n]; 

py=new double[n]; 

qx=new double[n]; 

qy=new double[n]; 

tt=new double[n]; 

dx=new double[n]; 

dy=new double[n]; 

int i, t, es; 

double bx3, bx4, by3, by4, cx, cy; 

bx4 = 0; 

by3 = 0; 

es = 3; 

px[0] = 1; 

py[0] = 1; 

px[n-1] = 1; 

py[n-1] = 1; 

if (n>1) 

{ 

for (i = 1;i<n;i++) 

tt[i] = Math.sqrt((x[i] - x[i - 1]) * (x[i] - x[i - 1]) + (y[i] - y[i - 1]) * (y[i] - y[i - 1])); 

switch(n) 

{ 

case 2: 

break; 

case 3: 

for (i = 1;i<n - 1;i++) 

{ 

a[i] = 2 * (tt[i] + tt[i + 1]); 

b[i] = tt[i + 1]; 

c[i] = tt[i]; 

dx[i] = 3 * (tt[i] * (x[i + 1] - x[i]) / tt[i + 1] + tt[i + 1] * (x[i] - x[i - 1]) / tt[i]); 

dy[i] = 3 * (tt[i] * (y[i + 1] - y[i]) / tt[i + 1] + tt[i + 1] * (y[i] - y[i - 1]) / tt[i]); 

} 



dx[1] = dx[1] - tt[2] * px[0]; 

dx[n - 2] = dx[n - 2] - tt[n - 2] * px[n-1]; 

dy[1] = dy[1] - tt[2] * py[0]; 

dy[n - 2] = dy[n - 2] - tt[n - 2] * py[n-1]; 



//注意，这是n=3的情况专有计算 

px[1] = dx[1] / a[1]; 

py[1] = dy[1] / a[1]; 



break; 

default: 

for (i = 1;i<n - 1;i++) 

{ 

a[i] = 2 * (tt[i] + tt[i + 1]); 

b[i] = tt[i + 1]; 

c[i] = tt[i]; 

dx[i] = 3 * (tt[i] * (x[i + 1] - x[i]) / tt[i + 1] + tt[i + 1] * (x[i] - x[i - 1]) / tt[i]); 

dy[i] = 3 * (tt[i] * (y[i + 1] - y[i]) / tt[i + 1] + tt[i + 1] * (y[i] - y[i - 1]) / tt[i]); 

} 

dx[1] = dx[1] - tt[2] * px[0]; 

dx[n - 2] = dx[n - 2] - tt[n - 2] * px[n-1]; 

dy[1] = dy[1] - tt[2] * py[0]; 

dy[n - 2] = dy[n - 2] - tt[n - 2] * py[n-1]; 

c[1] = c[1]/ a[1]; 

for (i = 2 ;i< n - 1;i++) 

{ 

a[i] = a[i] - b[i] * c[i - 1]; 

c[i] = c[i] / a[i]; 

} 

qx[1] = dx[1] / a[1]; 

qy[1] = dy[1] / a[1]; 

for (i = 2 ;i< n - 1;i++) 

{ 

qx[i] = (dx[i] - b[i] * qx[i - 1]) / a[i]; 

qy[i] = (dy[i] - b[i] * qy[i - 1]) / a[i]; 

} 

px[n - 2] = qx[n - 2]; 

py[n - 2] = qy[n - 2]; 

for (i = n - 3;i>=1;i--) 

{ 

px[i] = qx[i] - c[i] * px[i + 1]; 

py[i] = qy[i] - c[i] * py[i + 1]; 

} 

break; 

} 

for (i = 0 ;i< n - 1;i++) 

{ 

bx3 = (3 * (x[i + 1] - x[i]) / tt[i + 1] - 2 * px[i] - px[i + 1]) / tt[i + 1]; 

bx4 = ((2 * (x[i] - x[i + 1]) / tt[i + 1] + px[i] + px[i + 1]) / tt[i + 1]) / tt[i + 1]; 

by3 = (3 * (y[i + 1] - y[i]) / tt[i + 1] - 2 * py[i] - py[i + 1]) / tt[i + 1]; 

by4 = ((2 * (y[i] - y[i + 1]) / tt[i + 1] + py[i] + py[i + 1]) / tt[i + 1]) / tt[i + 1]; 

t = 0; 

while (t < tt[i + 1]) 

{ 

t = t + es; 

cx = x[i] + (px[i] + (bx3 + bx4 * t) * t) * t; 

cy = y[i] + (py[i] + (by3 + by4 * t) * t) * t; 

px2 = (int)cx; 

py2 = (int)cy; 

myGraphics.drawLine(px1,py1,px2,py2); 

px1 = px2; 

py1 = py2; 

} 

} 

} 

} 

}