javascript實現畫板功能
阿新 • • 發佈：2020-04-14
本文例項為大家分享了javascript實現畫板功能的具體程式碼，供大家參考，具體內容如下
畫板功能的實現
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
*{
margin: 0;
padding: 0;
list-style: none;
}
body{
background:url(11.jpg) 0 0 no-repeat;
}
.wrapper{
margin: 10px;
}
.wrapper canvas{
border: 1px solid blue;
border-radius:25px;
box-shadow: 10px 10px 5px brown;
margin-bottom: 16px;
background-color: #fff;
}
.wrapper .btn-list{
width: 1000px;
text-align: center;
}
.wrapper .btn-list li{
display: inline-block;
margin-left: 40px;
}
.wrapper .btn-list li input{
background-color: darkgreen;
color: blanchedalmond
border: none;
padding: 6px 13px;
cursor: pointer;
border-radius:25px;
font-size: 18px;
display: block;
transition-duration: 0.2s;
}
.wrapper .btn-list li input:hover{
border: 1px solid chocolate;
box-shadow: 0 12px 15px 0 rgba(0,0.5);
}
</style>
</head>
<body>
<!-- div.wrapper>canvas+ul.btn-list>li*5>input -->
<div class="wrapper">
<canvas class="cavs" width="1000" height="500"></canvas>
<ul class="btn-list">
<li><input type="color" id="colorBoard" value="colorBoard"></li>
<li><input type="button" id="cleanBoard" value="清屏"></li>
<li><input type="button" id="eraser" value="橡皮"></li>
<li><input type="button" id="rescind" value="撤銷"></li>
<li><input type="range" id="lineRuler" value="線條" min="1" max="30"></li>
</ul>
</div>
</body>
<script src="jquery-3.4.1.min.js"></script>
<script>
var drawingLineObj = {
cavs:$('.cavs'),context:$('.cavs').get(0).getContext('2d'),colorBoard:$('#colorBoard'),cleanBoard:$('#cleanBoard'),arrImg:[],eraser:$("#eraser"),rescind:$('#rescind'),lineRuler:$('#lineRuler'),bool:false,init:function(){
this.context.lineCap = 'round'; //線條起始與結尾樣式
this.context.lineJoin = 'round'; //轉彎
this.draw(); //畫筆函式
this.btnFn(); //按鈕函式
},draw:function(){
var cavs = this.cavs,self = this;
var c_x = cavs.offset().left,//canvas離左邊的距離
c_y = cavs.offset().top; //canvas離上邊的距離
cavs.mousedown(function(e){
e = e||window.event;
self.bool = true;
var m_x = e.pageX - c_x,//滑鼠點距離減去canvas離左邊的距離等於畫布點
m_y = e.pageY - c_y; //滑鼠點距離減去canvas離上邊的距離等於畫布點
self.context.beginPath();
self.context.moveTo(m_x,m_y);//滑鼠在畫布上的點
var imgData = self.context.getImageData(0,self.cavs[0].width,self.cavs[0].height);
self.arrImg.push(imgData);
//console.log(self.arrImg);
})
cavs.mousemove(function(e){
if(self.bool){ //定義一把鎖，防止滑鼠移開滑動
self.context.lineTo(e.pageX-c_x,e.pageY-c_y);
self.context.stroke(); //繪製出路徑
}
})
cavs.mouseup(function(){
self.context.closePath(); //結束自動閉合
self.bool = false; //滑鼠不移動時畫筆斷開
})
cavs.mouseleave(function(){
self.context.closePath(); //結束自動閉合
self.bool = false; //滑鼠不移動時畫筆斷開
})
},btnFn:function(){
var self = this;
$('.btn-list').on('click',function(e){
e = e||window.event;
switch(e.target.id){ //target
case 'cleanBoard':
self.context.clearRect(0,self.cavs[0].height) //[0]
break
case 'eraser':
self.context.strokeStyle = '#fff'
break
case 'rescind':
if(self.arrImg.length>0){
self.context.putImageData(self.arrImg.pop(),0);
break
}
}
})
this.colorBoard.change(function(e){ //當顏色變化時改變字型的顏色
self.context.strokeStyle = $(this).val();
})
this.lineRuler.change(function(e){ //線條的變化值
self.context.lineWidth = $(this).val();
})
}
}
drawingLineObj.init();
</script>
</html>
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。