刚坐在车里就开始电闪雷鸣。听着隆隆的雷声，没有恐慌，到有几分振奋人心的舒心感、酣畅淋漓感。朝外望去，突然间，狂风夹杂着骤雨席卷而来，一泻千里。瞬间暴雨如注，打在地上，溅起朵朵浪花，在热浪的蒸腾下激起层层水雾。满大街是慌乱的人群，行人跑着、叫喊着，唧唧喳喳的赶着在房檐下躲雨。这时候伞是没有用的，挡不住狂风暴雨的袭击，无论是带了伞的，还是没带伞的，全都躲在了房檐下。
最近公司在做一个签名的功能，主要用到了canvas画线的功能结合移动端touch事件
js部分是这样的：
window.onload = function() {
new lineCanvas({
el: document.getElementById("canvas"),//绘制canvas的父级div
clearEl: document.getElementById("clearCanvas"),//清除按钮
saveEl: document.getElementById("saveCanvas"),//保存按钮
// linewidth:1,//线条粗细，选填
// color:"black",//线条颜色，选填
// background:"#ffffff"//线条背景，选填
});
};
function lineCanvas(obj) {
this.linewidth = 1;
this.color = "#000000";
this.background = "#ffffff";
for (var i in obj) {
this[i] = obj[i];
};
this.canvas = document.createElement("canvas");
this.el.appendChild(this.canvas);
this.cxt = this.canvas.getContext("2d");
this.canvas.width = this.el.clientWidth;
this.canvas.height = this.el.clientHeight;
this.cxt.fillStyle = this.background;
this.cxt.fillRect(0, 0, this.canvas.width, this.canvas.width);
this.cxt.strokeStyle = this.color;
this.cxt.lineWidth = this.linewidth;
this.cxt.lineCap = "round";
//开始绘制
this.canvas.addEventListener("touchstart", function(e) {
this.cxt.beginPath();
this.cxt.moveTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY);
}.bind(this), false);
//绘制中
this.canvas.addEventListener("touchmove", function(e) {
this.cxt.lineTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY);
this.cxt.stroke();
}.bind(this), false);
//结束绘制
this.canvas.addEventListener("touchend", function() {
this.cxt.closePath();
}.bind(this), false);
//清除画布
this.clearEl.addEventListener("click", function() {
this.cxt.clearRect(0, 0, this.canvas.width, this.canvas.height);
}.bind(this), false);
//保存图片，直接转base64
this.saveEl.addEventListener("click", function() {
var imgBase64 = this.canvas.toDataURL();
console.log(imgBase64);
}.bind(this), false);
};
这是效果图：
附上html和css
<div id="canvas">
<p id="clearCanvas">清除</p>
<p id="saveCanvas">保存</p>
</div>
html,body{
width: 100%;
height: 100%;
}
#canvas{
width: 100%;
height: 100%;
position: relative;
}
#canvas canvas{
display: block;
}
#clearCanvas{
width: 50%;
height: 40px;
line-height: 40px;
text-align: center;
position: absolute;
bottom: 0;
left: 0;
border: 1px solid #DEDEDE;
z-index: 1;
}
#saveCanvas{
width: 50%;
height: 40px;
line-height: 40px;
text-align: center;
position: absolute;
bottom: 0;
right: 0;
border: 1px solid #DEDEDE;
z-index: 1;
}
以上就是html5 如何利用canvas手写签名并保存的如何实现方法。你知道，幸福不仅仅是吃饱穿暖，而是勇敢地去战胜困难。更多关于html5 如何利用canvas手写签名并保存的如何实现方法请关注haodaima.com其它相关文章！
