利用构造函数对canvas里面矩形与扇形的绘制进行一个封装
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>封装矩形构造函数，扇形构造函数</title>
<style>
canvas{
border: 1px solid green;
}
</style>
</head>
<body>
<!-- 封装矩形构造函数，扇形构造函数 -->
<canvas width="500" height="500" id="canvas"></canvas>
</body>
<script>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
function toAngle(radian){
return radian*180/Math.PI;
}
function toRadian(angle){
return angle*Math.PI/180;
}
// 封装矩形
function Rect(obj){
for(var key in obj){
this[key] = obj[key];
}
}
Rect.prototype = {
constuctor : Rect,
stroke : function(){
if(this.strokeStyle){
this.ctx.strokeStyle = this.strokeStyle;
}
this.ctx.strokeRect(this.x0,this.y0,this.width,this.height);
},
fill : function(){
if(this.fillStyle){
this.ctx.fillStyle = this.fillStyle;
}
this.ctx.fillRect(this.x0,this.y0,this.width,this.height)
}
}
var rect = new Rect({
ctx : ctx,
x0 : 100,
y0 : 100,
width : 100,
height : 100
})
rect.stroke();
//rect.fill();
//扇形封装
function Shan(obj){
for(var key in obj){
this[key] = obj[key];
}
}
Shan.prototype = {
constructor : Shan,
stroke : function(){
this.ctx.moveTo(this.x0,this.y0);
this.ctx.arc(this.x0,this.y0,this.randius,toRadian(this.start),toRadian(this.end));
this.ctx.closePath();
this.ctx.stroke();
},
fill : function(){
this.ctx.moveTo(this.x0,this.y0);
this.ctx.arc(this.x0,this.y0,this.randius,toRadian(this.start),toRadian(this.end));
this.ctx.fill();
}
}
var shan = new Shan({
ctx : ctx,
x0 : 200,
y0 : 340,
randius : 50,
start : -90,
end : 60
})
shan.stroke();
//shan.fill();
</script>
</html>
一混五六年
