中国国旗图片生成代码-jsp版本

图片截图如下：

具体代码如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page contentType="image/jpeg" import="java.awt.*,
java.awt.image.*,java.util.*,javax.imageio.*,java.awt.Shape.*,java.awt.geom.*,com.sun.image.codec.jpeg.*" %>
<%
  out.clear();
  response.setContentType("image/jpeg");
  response.setHeader("Pragma","No-cache");
  response.setHeader("Cache-Control","no-cache");
  response.setDateHeader("Expires", 0);
  int width =300;
  int height = width/3*2; 
     double maxR = 0.15, minR = 0.05; 
     double maxX = 0.50, maxY = 0.50; 

     double[] minX = {0.75, 0.85, 0.85, 0.75}; 
     double[] minY = {0.35, 0.45, 0.60, 0.70}; 
  BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
  java.awt.Graphics2D g=(java.awt.Graphics2D)image.createGraphics();
  g.clearRect(0, 0,width,height);
  g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  
  //画棋面
  g.setColor(java.awt.Color.red);
  g.fillRect(0, 0, width, height);
  //g.fillRect(50, 50, width, height);
  g.setColor(java.awt.Color.yellow);
  
  //画大五角星
        double ox = height*maxX, oy = height*maxY;
  g.fill(createPentacle(ox,oy,height*maxR,-Math.PI/2)); 
  
  //画小五角星
        for(int idx =0;idx < 4;idx ++){ 
            double sx = minX[idx]*height, sy = minY[idx]*height; 
            double theta = Math.atan2(oy-sy,ox-sx); 
            g.fill(createPentacle(sx,sy,height*minR,theta)); 
        } 

  g.dispose();
  out.clearBuffer();
  out = pageContext.pushBody();
  //ImageIO.write(image, "JPEG", response.getOutputStream());
   ServletOutputStream outStream = response.getOutputStream();
        JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(outStream);
        encoder.encode(image);
        outStream.close();
%>
<%!
 public static java.awt.Shape createPentacle(double sx, double sy, double radius,double theta) {
  final double arc = Math.PI / 5;
  final double rad = Math.sin(Math.PI / 10) / Math.sin(3 * Math.PI / 10);
  GeneralPath path = new GeneralPath();
  path.moveTo(1, 0);
  for (int idx = 0; idx < 5; idx++) {
   path.lineTo(rad * Math.cos((1 + 2 * idx) * arc),rad * Math.sin((1 + 2 * idx) * arc));
   path.lineTo(Math.cos(2 * (idx + 1) * arc),Math.sin(2 * (idx + 1) * arc));
  }
  path.closePath();
  AffineTransform atf = AffineTransform.getScaleInstance(radius, radius);
  atf.translate(sx / radius, sy / radius);
  atf.rotate(theta);
  return atf.createTransformedShape(path);
 }
%>

将代码另存为jsp文件，放在运行目录下执行即可。

代码在tomcat6.0下测试通过