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Add canvas-demo
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@lin-xin
lin-xin committed May 22, 2017
1 parent 0edc5a0 commit 60facb5
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39 changes: 39 additions & 0 deletions canvas-demo/chart.html
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<!DOCTYPE html>
<html lang="en">
<head>
<title></title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
<style>
.main{
padding: 50px;
text-align: center;
}
</style>
</head>
<body>
<div class="main"><canvas id="canvas" width="500" height="400"></canvas></div>


<script src="sChart.js"></script>
<script>
var data = [
{xAxis:'2012',value:2141},
{xAxis:'2013',value:1499},
{xAxis:'2014',value:3260},
{xAxis:'2015',value:1170},
{xAxis:'2016',value:970},
{xAxis:'2017',value:2350}
]
var chart = new sBarChart('canvas',data,{
title: 'xxx公司年度盈利',
bgColor: '#829dba',
titleColor: '#ffffff', // 标题颜色
titlePosition: 'top', // 标题位置
fillColor: '#72f6ff', // 柱状填充色
axisColor: '#eeeeee', // 坐标轴颜色
contentColor: '#bbbbbb' // 内容横线颜色
});
</script>
</body>
</html>
205 changes: 205 additions & 0 deletions canvas-demo/sChart.js
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function sBarChart(canvas, data, options) {
this.canvas = document.getElementById(canvas);
this.ctx = this.canvas.getContext('2d');
this.data = data; // 存放图表数据
this.dataLength = this.data.length; // 图表数据的长度
this.width = this.canvas.width; // canvas 宽度
this.height = this.canvas.height; // canvas 高度
this.padding = 50; // canvas 内边距
this.yEqual = 5; // y轴分成5等分
this.yLength = 0; // y轴坐标点之间的真实长度
this.xLength = 0; // x轴坐标点之间的真实长度
this.yFictitious = 0; // y轴坐标点之间显示的间距
this.yRatio = 0; // y轴坐标真实长度和坐标间距的比
this.bgColor = '#ffffff'; // 默认背景颜色
this.fillColor = '#1E9FFF'; // 默认填充颜色
this.axisColor = '#666666'; // 坐标轴颜色
this.contentColor = '#eeeeee'; // 内容横线颜色
this.titleColor = '#000000'; // 图表标题颜色
this.title = ''; // 图表标题
this.titlePosition = 'top'; // 图表标题位置: top / bottom
this.looped = null; // 是否循环
this.current = 0; // 当前加载柱状图高度的百分数
this.currentIndex = -1;
this.onceMove = -1;
this.init(options);
}
sBarChart.prototype = {
init: function(options) {
if(options){
this.padding = options.padding || 50;
this.yEqual = options.yEqual || 5;
this.bgColor = options.bgColor || '#ffffff';
this.fillColor = options.fillColor || '#1E9FFF';
this.axisColor = options.axisColor || '#666666';
this.contentColor = options.contentColor || '#eeeeee';
this.titleColor = options.titleColor || '#000000';
this.title = options.title;
this.titlePosition = options.titlePosition || 'top';
}
this.yLength = Math.floor((this.height - this.padding * 2 - 10) / this.yEqual);
this.xLength = Math.floor((this.width - this.padding * 1.5 - 10) / this.dataLength);
this.yFictitious = this.getYFictitious(this.data);
this.yRatio = this.yLength / this.yFictitious;
this.looping();
},
looping: function() {
this.looped = requestAnimationFrame(this.looping.bind(this));
if(this.current < 100){
this.current = (this.current + 3) > 100 ? 100 : (this.current + 3);
this.drawAnimation();
}else{
window.cancelAnimationFrame(this.looped);
this.looped = null;
this.watchHover();
}
},
drawAnimation: function() {
for(var i = 0; i < this.dataLength; i++) {
var x = Math.ceil(this.data[i].value * this.current / 100 * this.yRatio);
var y = this.height - this.padding - x;

this.data[i].left = this.padding + this.xLength * (i + 0.25);
this.data[i].top = y;
this.data[i].right = this.padding + this.xLength * (i + 0.75);
this.data[i].bottom = this.height - this.padding;
this.drawUpdate();
}
},
drawUpdate: function() {
this.ctx.fillStyle = this.bgColor;
this.ctx.fillRect(0, 0, this.width, this.height);
this.drawAxis();
this.drawPoint();
this.drawTitle();
this.drawChart();
},
drawChart: function() {
this.ctx.fillStyle = this.fillColor;
for(var i = 0; i < this.dataLength; i++) {
this.ctx.fillRect(
this.data[i].left,
this.data[i].top,
this.data[i].right - this.data[i].left,
this.data[i].bottom - this.data[i].top
);
this.ctx.font = '12px Arial'
this.ctx.fillText(
this.data[i].value * this.current / 100,
this.data[i].left + this.xLength / 4,
this.data[i].top - 5
);
}
},
drawAxis: function() {
this.ctx.beginPath();
this.ctx.strokeStyle = this.axisColor;
// y轴线, +0.5是为了解决canvas画1像素会显示成2像素的问题
this.ctx.moveTo(this.padding + 0.5, this.height - this.padding + 0.5);
this.ctx.lineTo(this.padding + 0.5, this.padding + 0.5);
// x轴线
this.ctx.moveTo(this.padding + 0.5, this.height - this.padding + 0.5);
this.ctx.lineTo(this.width - this.padding / 2 + 0.5, this.height - this.padding + 0.5);
this.ctx.stroke();
},
drawPoint: function() {
// x轴坐标点
this.ctx.beginPath();
this.ctx.font = '12px Microsoft YaHei';
this.ctx.textAlign = 'center';
this.ctx.fillStyle = this.axisColor;
for(var i = 0; i < this.dataLength; i ++){
var xAxis = this.data[i].xAxis;
var xlen = this.xLength * (i + 1);
this.ctx.moveTo(this.padding + xlen + 0.5, this.height - this.padding + 0.5);
this.ctx.lineTo(this.padding + xlen + 0.5, this.height - this.padding + 5.5);
this.ctx.fillText(xAxis, this.padding + xlen - this.xLength / 2, this.height - this.padding + 15);
}
this.ctx.stroke();

// y轴坐标点
this.ctx.beginPath();
this.ctx.font = '12px Microsoft YaHei';
this.ctx.textAlign = 'right';
this.ctx.fillStyle = this.axisColor;
this.ctx.moveTo(this.padding + 0.5, this.height - this.padding + 0.5);
this.ctx.lineTo(this.padding - 4.5, this.height - this.padding + 0.5);
this.ctx.fillText(0, this.padding - 10, this.height - this.padding + 5);
for(var i=0; i < this.yEqual; i ++){
var y = this.yFictitious * (i + 1);
var ylen = this.yLength * (i + 1);
this.ctx.beginPath();
this.ctx.strokeStyle = this.axisColor;
this.ctx.moveTo(this.padding + 0.5, this.height - this.padding - ylen + 0.5);
this.ctx.lineTo(this.padding - 4.5, this.height - this.padding - ylen + 0.5);
this.ctx.stroke();
this.ctx.fillText(y,this.padding - 10, this.height - this.padding - ylen + 5);
this.ctx.beginPath();
this.ctx.strokeStyle = this.contentColor;
this.ctx.moveTo(this.padding + 0.5, this.height - this.padding - ylen + 0.5)
this.ctx.lineTo(this.width - this.padding / 2 + 0.5, this.height - this.padding - ylen+0.5);
this.ctx.stroke();
}
},
drawTitle: function() {
if(this.title){
this.ctx.beginPath();
this.ctx.textAlign = 'center';
this.ctx.fillStyle = this.titleColor;
this.ctx.font = '16px Microsoft YaHei';
if(this.titlePosition === 'bottom' && this.padding >= 40){
this.ctx.fillText(this.title, this.width / 2, this.height - 5)
}else{
this.ctx.fillText(this.title, this.width / 2, this.padding / 2)
}
}
},
/**
* 监听鼠标移动事件
*/
watchHover: function() {
var self = this;
self.canvas.addEventListener('mousemove', function(ev) {
ev = ev || window.event;
self.currentIndex = -1;
for (var i = 0; i < self.data.length; i ++){
if( ev.offsetX > self.data[i].left &&
ev.offsetX < self.data[i].right &&
ev.offsetY > self.data[i].top &&
ev.offsetY < self.data[i].bottom )
{
self.currentIndex = i;
}
}
self.drawHover();
})
},
drawHover: function() {
if(this.currentIndex !== -1){
if(this.onceMove === -1){
this.onceMove = this.currentIndex;
this.canvas.style.cursor = 'pointer';
}
}else{
if(this.onceMove !== -1){
this.onceMove = -1;
this.canvas.style.cursor = 'inherit';
}
}
},
/**
* y轴坐标点之间显示的间距
* @param data
* @return y轴坐标间距
*/
getYFictitious: function(data) {
var arr = data.slice(0);
arr.sort(function(a,b){
return -(a.value-b.value);
});
var len = Math.ceil(arr[0].value / this.yEqual);
var pow = len.toString().length - 1;
pow = pow > 2 ? 2 : pow;
return Math.ceil(len / Math.pow(10,pow)) * Math.pow(10,pow);
}
}

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