jsp实现生成中国国旗图片效果代码

<%@ 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); } %>