js简单的插件（折线图）
自己做的一个简单的折线图，html代码如下
<head>
<meta charset="UTF-8">
<title>折线图title>
<style>
#container{
height: 600px;
background-image: url("../../day09-20181213/nybj.png");
background-size: 100% 100%;
}
style>
head>
<body>
<div id="container">div>
body>
js代码如下
<script>
var obj = {
id:"container",
width:1300,
height:500,
datas:[
{
name:"青岛",
color:"red",
data:[30,20,40,21,23,16,33,20,13,21,10,1]
},
{
name:"烟台",
color:"orange",
data:[26,21,33,30,24,20,25,10,8,5,8,10]
},
{
name:"威海",
color:"green",
data:[42,33,28,18,20,33,25,16,15 ,16,23,3]
},
],
startX:60,
startY:450,
labelColor:"white",
labelCount:10,
nameSpace : 80,
circleColor:"blue",
tip:"山东省各个城市12个月的平均温度"
};
drawLine1(obj);
function drawLine1(obj) {
var id = obj.id;
var datas = obj.datas;
var width = obj.width;
var height = obj.height;
var startX = obj.startX;
var startY = obj.startY;
var labelColor = obj.labelColor;
var labelCount = obj.labelCount;
var nameSpace = obj.nameSpace;
var tip = obj.tip;
var circleColor = obj.circleColor;
var container = document.getElementById(id);
var canvas = document.createElement("canvas");
canvas.width = width;
canvas.height = height;
canvas.style.border = "1px solid red";
container.appendChild(canvas);
var cvs = canvas.getContext("2d");
cvs.beginPath();
cvs.strokeStyle = "white";
var startY1 = 50;
cvs.moveTo(startX, startY1);
cvs.lineTo(startX, startY);
cvs.lineTo(1200, startY);
cvs.stroke();
var length = datas.length;
var length1 = datas[0].data.length;
var maxNum = 0;
for(var i = 0;i < length;i++){
for (var j = 0;j < length1;j++){
if (maxNum <= datas[i].data[j]) {
maxNum = datas[i].data[j];
}
}
}
maxNum = maxNum * 1.1;
var increment = (startY - startY1) / maxNum;
var labelSpace = (startY - startY1) / labelCount;
for (var i = 0; i <= labelCount; i++) {
var text = Math.round((maxNum / labelCount) * i);
cvs.beginPath();
cvs.fillStyle = labelColor;
cvs.fillText(text, startX - 40, startY - (labelSpace * i ) );
cvs.closePath();
cvs.fill();
}
var start = 0;
var end = 0;
var titleSpace = 30;
for (let i = 0;i < length ;i++) {
var k = 100;
for (let j = 0; j < length1; j++) {
// end = length1 * (i + 1);
// start = i * length1;
//折线
setTimeout(function () {
cvs.beginPath();
cvs.strokeStyle = datas[i].color;
cvs.moveTo(startX + nameSpace * (j + 1), (startY1 + (maxNum - datas[i].data[j]) * increment ));
cvs.lineTo(startX + nameSpace * (j + 2), (startY1 + (maxNum - datas[i].data[j + 1]) * increment));
cvs.stroke();
}, k += 100);
end = length1 * (i + 1);
start = i * length1;
//圆点
cvs.beginPath();
cvs.fillStyle = circleColor;
cvs.arc(startX + nameSpace * (j + 1), (startY1 + (maxNum - datas[i].data[j]) * increment ), 4, 0, Math.PI * 2)
cvs.closePath();
cvs.fill();
}
cvs.beginPath();
cvs.strokeStyle = datas[i].color;
cvs.moveTo(1050, 40 + titleSpace * i);
cvs.lineTo(1100, 40 + titleSpace * i);
cvs.stroke();
cvs.closePath();
cvs.beginPath();
cvs.fillStyle = datas[i].color;
cvs.font = "15px 宋体";
cvs.fillText(datas[i].name, 1130, 45 + titleSpace * i);
cvs.stroke();
cvs.closePath();
}
cvs.beginPath();
cvs.fillStyle = labelColor;
cvs.fillText(tip,20,30);
cvs.closePath();
cvs.fill();
for(var k = 0;k < length1;k++){
cvs.beginPath();
cvs.fillStyle = labelColor;
cvs.fillText((k + 1) + "月份", startX + nameSpace * (k + 1) - 10, startY + 30 );
cvs.closePath();
cvs.fill();
}
}
</script>
结果如下（动画效果没有展示）
