话不多说,最终实现效果如下:
图中难点:
- 圆角矩形绘制;转载他人帖子:看此处:https://www.aspzz.cn/article/...
- 最左或者最右边的气泡需要做动态偏移
本项目是由mpvue写的小程序:所以用的是vue的书写格式(微信小程序可以自行修改): 使用方法:
- 将下列代码新建linechart.vue文件
- 再项目中调用本组件的drawAll方法传入日期和值即可
代码中有少量注解请不懂的给我留言
<template>
<div class="linechart">
<canvas class="circle" canvas-id="canvasline" style="width: 750rpx;height: 280rpx;">
</canvas></div>
</template>
<script>
export default {
data() {
return {
canvasWidth: 375,canvasHeight: 123,date: ['-/-','-/-'],value: [0,8,128);">10,128);">6,],len: 4,xcoords: []
}
},onLoad() {
this.drawAll()
},methods: {
drawAll(date,value) {
this.date = date || this.date
this.value = value || this.value
var ctx = wx.createCanvasContext('canvasline')
this.roundRect(ctx,this.px2PX(10),this.px2PX(this.canvasWidth) - this.px2PX(20),this.px2PX(this.canvasHeight),128);">8),68);">'#F5F3ED');
this.drawYLine(ctx,128);">55),128);">1),68);">'white')
this.drawXLine(ctx,this.len,68);">'white');
this.drawLine(ctx,128);">1.5),128);">3))
ctx.draw()
},px2PX(px) {
return (wx.getSystemInfoSync().screenWidth / 375) * Number(px)
},
roundRect(ctx,x,y,w,h,r,fillColor) {
if (w < 2 * r) r = w / 2;
if (h < 2 * r) r = h / 2;
ctx.beginPath()
ctx.arc(x + r,y + r,Math.PI,Math.PI * 1.5)
ctx.moveTo(x + r,y)
ctx.lineTo(x + w - r,y)
ctx.lineTo(x + w,y + r)
ctx.arc(x + w - r,128);">1.5,128);">2)
ctx.lineTo(x + w,y + h - r)
ctx.lineTo(x + w - r,y + h)
ctx.arc(x + w - r,y + h - r,128);">0.5)
ctx.lineTo(x + r,y + h)
ctx.lineTo(x,y + h - r)
ctx.arc(x + r,128);">0.5,Math.PI)
ctx.lineTo(x,y + r)
ctx.lineTo(x + r,y)
ctx.setFillStyle(fillColor);
ctx.fill()
ctx.closePath()
},68);">@param {number,number,number} x1,y1,x2,y2 第一条线的起始坐标和结束坐标
* @param {number} spacing 线条直接的间隔
* @param {number} lineWidth 线条宽度
* @param {color} color线条的颜色
*/
drawYLine(ctx,x1,y2,spacing,lineWidth,color) {
ctx.beginPath();
let width = this.px2PX(this.canvasWidth) - (x1 * 2)
let len = Math.floor(width /spacing)
for (let i = 0; i <= len; i++) {
let spaced = spacing * i + i;
this.xcoords.push(x1 + spaced)
ctx.setLineWidth(lineWidth)
ctx.setStrokeStyle(color)
ctx.moveTo(x1 + spaced,y1);
ctx.lineTo(x2 + spaced,y2);
ctx.setFontSize(this.px2PX(12));
ctx.setTextAlign('center');
ctx.setFillStyle('#DFDACD');
ctx.fillText(this.date[i],x1 + spaced,y2 + this.px2PX(14))
}
ctx.stroke()
},68);">@param {number} len 绘制多少条横线
* // 绘制横线网格
drawXLine(ctx,len,color) {
ctx.beginPath();
let spaced = this.px2PX(this.canvasHeight) / len
let x = this.px2PX(this.canvasWidth)
for (let i = 0; i < len; i++) {
let hei = spaced * i + i
ctx.moveTo(@param {number} width 折线的线条宽度
* @param {number} r 折线拐角的圆的半径
*/
drawLine(ctx,width,r) {
let arrMax = Math.max.apply({},this.value)
let height = this.px2PX(this.canvasHeight)
let hei = this.px2PX(this.canvasHeight) - this.px2PX(24)
let average = arrMax <= 0 ? 0 : hei / arrMax
let len = this.value.length - 1
ctx.beginPath();
for (let i = 0; i < len; i++) {
let x1 = this.xcoords[i],y1 = height - this.value[i] * average,x2 = this.xcoords[i+1],y2 = height - this.value[i + 1] * average
ctx.moveTo(x1,y1)
ctx.lineTo(x2,y2)
}
ctx.setStrokeStyle('#F9B213');
ctx.setLineWidth(width);
ctx.stroke()
ctx.beginPath();
for (let i = this.value[i + /* 折线区域 */
ctx.setFillStyle('rgba(249,178,19,0.08)');
ctx.fill();
for (let i = 0; i <= len; i++) {
let x1 = this.xcoords[i],y1 = height - this.value[i] * average
ctx.beginPath();
ctx.arc(x1,128);">2 * Math.PI)
ctx.setStrokeStyle('#F9B213');
ctx.setLineWidth(width);
ctx.setFillStyle('white');
ctx.fill();
ctx.stroke()
}
for (let i = this.value[i] * average
let defaultWidth = this.px2PX(24),defaultHeight = this.px2PX(16)
let fontsize = this.px2PX(10)
let lense = this.value[i].toString().length
if (lense > 1) {
defaultWidth = defaultWidth + lense * fontsize / 2.5
}
let x = x1 - defaultWidth / 2
let y = y1 - defaultHeight - r * 2
if (i === 0) {
x = x1 - fontsize / 2
ctx.setTextAlign('left');
} else if (i === len) {
x = x - defaultWidth / 2 + fontsize / 'right');
} else {
ctx.setTextAlign('center');
}
this.roundRect(ctx,defaultWidth,defaultHeight,68);">'white')
ctx.beginPath();
ctx.setFontSize(fontsize);
ctx.setFillStyle('#F9B213');
ctx.fillText('+'+this.value[i],y1 - this.px2PX(10))
ctx.closePath()
}
}
}
}
</script>
<style lang="scss">
.linechart {
width: 750upx;
height: 280upx;
}
</style>
以上列子如有疑问,请给我留言。 (编辑:李大同)
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