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@@ -0,0 +1,106 @@
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+<!doctype html>
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+<html lang="en">
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+<head>
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+ <meta charset="UTF-8" />
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+ <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
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+ <title> canvas 手写毛笔字效果 </title>
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+ <style type="text/css">
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+ #canvasId {
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+ background-color: #FFFFcc;
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+ }
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+ </style>
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+</head>
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+<body>
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+
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+<canvas id="canvasId" width="700" height="500"></canvas><br />
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+<input type="button" value="clear" οnclick="hw.clear();" />
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+
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+<script type="text/javascript">
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+ function Handwriting(id) {
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+ this.canvas = document.getElementById(id);
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+ this.ctx = this.canvas.getContext("2d");
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+ this.ctx.fillStyle = "rgba(0,0,0,0.25)";
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+ var _this = this;
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+ this.canvas.onmousedown = function (e) { _this.downEvent(e)};
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+ this.canvas.onmousemove = function (e) { _this.moveEvent(e)};
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+ this.canvas.onmouseup = function (e) { _this.upEvent(e)};
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+ this.canvas.onmouseout = function (e) { _this.upEvent(e)};
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+ this.moveFlag = false;
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+ this.upof = {};
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+ this.radius = 0;
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+ this.has = [];
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+ this.lineMax = 30;
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+ this.lineMin = 3;
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+ this.linePressure = 1;
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+ this.smoothness = 80;
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+ }
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+
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+ Handwriting.prototype.clear = function () {
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+ this.ctx.clearRect(0,0,this.canvas.width,this.canvas.height);
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+ }
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+
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+ Handwriting.prototype.downEvent = function (e) {
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+ this.moveFlag = true;
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+ this.has = [];
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+ this.upof = this.getXY(e);
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+ }
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+
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+ Handwriting.prototype.moveEvent = function (e) {
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+ if (!this.moveFlag)
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+ return;
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+ var of = this.getXY(e);
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+ var up = this.upof;
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+ var ur = this.radius;
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+ this.has.unshift({time:new Date().getTime() ,dis:this.distance(up,of)});
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+ var dis = 0;
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+ var time = 0;
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+ for (var n = 0; n < this.has.length-1; n++) {
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+ dis += this.has[n].dis;
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+ time += this.has[n].time-this.has[n+1].time;
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+ if (dis>this.smoothness)
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+ break;
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+ }
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+ var or = Math.min(time/dis*this.linePressure+this.lineMin , this.lineMax) / 2;
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+ this.radius = or;
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+ this.upof = of;
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+ if (this.has.length<=4)
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+ return;
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+ var len = Math.round(this.has[0].dis/2)+1;
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+ for (var i = 0; i < len; i++) {
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+ var x = up.x + (of.x-up.x)/len*i;
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+ var y = up.y + (of.y-up.y)/len*i;
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+ var r = ur + (or-ur)/len*i;
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+ this.ctx.beginPath();
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+ this.ctx.arc(x,y,r,0,2*Math.PI,true);
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+ this.ctx.fill();
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+ }
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+ }
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+
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+ Handwriting.prototype.upEvent = function (e) {
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+ this.moveFlag = false;
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+ }
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+
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+ Handwriting.prototype.getXY = function (e)
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+ {
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+ return {
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+ x : e.clientX - this.canvas.offsetLeft + (document.body.scrollLeft || document.documentElement.scrollLeft),
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+ y : e.clientY - this.canvas.offsetTop + (document.body.scrollTop || document.documentElement.scrollTop)
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+ }
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+ }
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+
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+ Handwriting.prototype.distance = function (a,b)
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+ {
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+ var x = b.x-a.x , y = b.y-a.y;
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+ return Math.sqrt(x*x+y*y);
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+ }
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+
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+ var hw = new Handwriting("canvasId");
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+ hw.lineMax = 40;
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+ hw.lineMin = 5;
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+ hw.linePressure = 2.5;
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+ hw.smoothness = 100;
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+
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+</script>
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+</body>
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+</html>
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+
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