原始图片:(270*600)
html:
<div class="back" >
<canvas id="map1" width="270px" height="600px">
</canvas>
</div>
js:
function draw(id){
var map=document.getElementById(id);
var pan=map.getContext("2d");
pan.beginPath();
// pan.strokeStyle="rgba(99,20,50,0.7)";
pan.fillStyle="rgba(17,14,14,0.7)";
pan.moveTo(0,0);
pan.lineTo(270,0);
pan.lineTo(270,600);
pan.lineTo(0,600);
pan.closePath();
pan.fill();
// pan.stroke(); 绘制此路径
// pan.clearRect(0,0,270,600);
}
处理后: