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- 概览
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趣味编程小画板是一款使用javaScript脚本及Java2D技术编程绘图的小软件。
- 特性
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- 截图
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- 下载
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趣味编程小画板基于Java Web start技术,点此安装运行
- 教学
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- 第一课：画线 从点[0,0] 到 点[100,100]
- g.clearRect(0,0,1000,1000);
g.drawLine(0,0,100,100);
- 第二课：画多边形、直角坐标及sin函数图像
- importPackage(javax.swing);
importPackage(java.awt.geom);
importPackage(java.awt);
//clear screen
g.setBackground(Color.WHITE);
g.clearRect(0,0,10000,10000);
g.setColor(Color.RED);
var polygon=new Polygon();
//polygon
polygon.addPoint(100,50);
polygon.addPoint(150,30);
polygon.addPoint(200,160);
polygon.addPoint(120,180);
g.fill(polygon);
//coordinate
var path=new GeneralPath();
path.moveTo(-10,400);
for(var x=-10;x<=200;x+=10){
path.lineTo(20+x,400);
}
g.draw(path);
g.drawString("x",220,400);
path.reset();
path.moveTo(20,190);
for(var y=-10;y<=220;y+=10){
path.lineTo(20,200+y);
}
g.draw(path);
g.drawString("y",20,190);
var p=new GeneralPath();
p.moveTo(20+0.0,400+Math.sin(0.0));
for(var x=0.0;x<=Math.PI;x+=0.1){
var y=Math.sin(x);
g.drawString("x="+x+"|y="+y,300,x*150);
p.lineTo(x*50+20,y*50+400);
}
g.draw(p);
- 第三课：子程序
- importPackage(java.awt);
importPackage(java.awt.geom);
function drawTriangle(pt1x,pt1y,pt2x,pt2y,pt3x,pt3y){
var p=new Polygon();
p.addPoint(pt1x,pt1y);
p.addPoint(pt2x,pt2y);
p.addPoint(pt3x,pt3y);
g.fill(p);
}
//draw coordanate
g.clearRect(0,0,1000,1000);
//draw
drawTriangle(100,100,150,100,150,130);
//o=[200,200]
g.fillRect(200,200,4,4);
g.drawLine(100,100,300,300);
g.drawLine(150,100,250,300);
g.drawLine(150,130,250,270);
g.setColor(Color.RED);
//draw polygon
drawTriangle(300,300,250,300,250,270);
- 第四课：分形图案
- importPackage(java.awt);
importPackage(java.awt.geom);
g.clearRect(0,0,1000,1000);
function getX(ox,r,angle){
var ret=0;
var arc=Math.PI*angle/180;
ret=ox+r*Math.cos(arc);
return ret;
}
function getY(oy,r,angle){
var ret=0;
var arc=Math.PI*angle/180;
ret=oy+r*Math.sin(arc);
return ret;
}
function drawMyShape(ox,oy,r,numAngle,level){
if(level<1){
return;
}
var color=new Color(Math.random(),Math.random(),Math.random());
g.setColor(color);
g.draw(new Ellipse2D.Float(ox-r,oy-r,2*r,2*r));
var p=new Polygon();
for(var i=1;i<=numAngle;i++){
var angle=360*i/numAngle;
var x=getX(ox,r,angle);
var y=getY(oy,r,angle);
p.addPoint(x,y);
drawMyShape(x,y,r,numAngle,level-1);
}
g.setColor(color);
g.draw(p);
}
var r=100;
var ox=300;
var oy=300;
drawMyShape(150,200,50,3,3);
drawMyShape(500,200,50,4,3);
drawMyShape(150,500,50,5,3);
drawMyShape(500,500,50,6,3);
- 第五课：函数图像
- importPackage(java.awt);
importPackage(java.awt.geom);
g.clearRect(0,0,2000,2000);
function getRel(relV,oV,unit){
return (relV-oV)*unit;
}
function getRange(data){
var min=data[0];
var max=data[0];
for(var i=0;i if(data[i]>max){
max=data[i];
}
if(data[i] min=data[i];
}
}
return max-min;
}
function drawFuncLine(arrayX,func,absox,absoy,width,height,autoScaleAxis,showValue){
g.drawRect(absox-1,absoy-1,2,2);
var arrayY=new Array();
for(var i=0;i arrayY.push(func(arrayX[i]));
}
var temp=getRange(arrayX);
var unitX=0;
if(temp!=0){
unitX=(width-50)/temp;
}
temp=getRange(arrayY);
var unitY=0;
if(temp!=0){
unitY=(height-50)/temp;
}
if(autoScaleAxis==null||!autoScaleAxis){
unitX=1;
unitY=1;
}
for(var i=0;i var x=absox+getRel(arrayX[i],arrayX[0],unitX);
var y=absoy-getRel(arrayY[i],arrayY[0],unitY);
if(i-1>=0){
var prevX=absox+getRel(arrayX[i-1],arrayX[0],unitX);
var prevY=absoy-getRel(arrayY[i-1],arrayY[0],unitY);
g.drawLine(prevX,prevY,x,y);
}
if(showValue){
g.drawString("x="+arrayX[i]+"|y="+arrayY[i],x,y);
}
}
}
function buildArray(first,last,step){
var ret=new Array();
for(var i=first;i<=last;i+=step){
ret.push(i);
}
return ret;
}
function myGetY(x){
var ret=0;
// var ret=x*x;
//var ret=x*x*x;
//ret=5;
if(x==0){
ret=0;
}else{
ret=1000/x;
}
//ret=x*x;
//ret=10*x;
ret=x*x/2;
return ret;
}
//var arrayX=buildArray(-Math.PI*5,Math.PI*5,0.05);
//drawFuncLine(arrayX,Math.sin,50,100,500,300,false);
var arrayX=buildArray(-60,60,5);
drawFuncLine(arrayX,function(x){return 3*x*x+2*x;},50,300,300,300,true,true);
drawFuncLine(arrayX,function(x){return -3*x*x+2*x;},50,600,300,300,true,false);
- 参考
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- 更新记录
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- 2009-8-5 发布趣味编程小画板 1.0beta.
- 开发计划
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