示例源码如下，请查看 pre > code 标签中的内容
<template>
<!-- #ifdef APP -->
<scroll-view class="page-scroll-view">
<!-- #endif -->
<view>
<view class="drawing" id="draw-text-view"></view>
<view class="drawing" id="draw-line-view"></view>
<view class="drawing" id="draw-circle-view"></view>
<view class="drawing" id="draw-dash-line"></view>
<view class="drawing" id="draw-house"></view>
<view class="drawing" id="draw-style"></view>
<view class="drawing" id="draw-odd"></view>
<view class="drawing" id="draw-arcto"></view>
</view>
<!-- #ifdef APP -->
</scroll-view>
<!-- #endif -->
</template>
<script>
var y = 160
export default {
data() {
return {
texts: [
'HBuilderX，轻巧、极速，极客编辑器',
'uni-app x，终极跨平台方案',
'uniCloud，js serverless云服务',
'uts，大一统语言',
'uniMPSdk，让你的App具备小程序能力',
'uni-admin，开源、现成的全端管理后台',
'uni-id，开源、全端的账户中心',
'uni-pay，开源、云端一体、全平台的支付',
'uni-ai，聚合ai能力',
'uni-cms，开源、云端一体、全平台的内容管理平台',
'uni-im，开源、云端一体、全平台的im即时消息',
'uni统计，开源、完善、全平台的统计报表',
'......'
] as string[]
}
},
onShow() {
},
onReady() {
this.drawText()
this.drawLines()
this.drawCircles()
this.drawStar()
this.drawhouse()
this.drawPoint()
this.drawRect()
this.drawArcTo()
},
onUnload() {
y = 160
},
methods: {
drawText() {
let element = uni.getElementById('draw-text-view')!
let ctx = element.getDrawableContext()!
let width = element.getBoundingClientRect().width
ctx.reset()
ctx.font = "15px Arial"
ctx.textAlign = "center"
for (var i = 0; i < this.texts.length; i++) {
let value = this.texts[i]
if (i % 2 == 0) {
ctx.fillText(value, width / 2, (20 * (i + 1)))
} else {
ctx.lineWidth = 0.5
ctx.strokeText(value, width / 2, (20 * (i + 1)))
}
}
ctx.update()
},
drawLines() {
let ctx = uni.getElementById('draw-line-view')!.getDrawableContext()!
ctx.reset()
ctx.lineWidth = 10;
["round", "bevel", "miter"].forEach((join, i) => {
ctx.lineJoin = join;
ctx.beginPath();
ctx.moveTo(5, 10 + i * 40);
ctx.lineTo(50, 50 + i * 40);
ctx.lineTo(90, 10 + i * 40);
ctx.lineTo(130, 50 + i * 40);
ctx.lineTo(170, 10 + i * 40);
ctx.stroke();
});
ctx.lineWidth = 1
var space = 170
ctx.strokeStyle = '#09f';
ctx.beginPath();
ctx.moveTo(10 + space, 10);
ctx.lineTo(140 + space, 10);
ctx.moveTo(10 + space, 140);
ctx.lineTo(140 + space, 140);
ctx.stroke();
// Draw lines
ctx.strokeStyle = 'black';
['butt', 'round', 'square'].forEach((lineCap, i) => {
ctx.lineWidth = 15;
ctx.lineCap = lineCap;
ctx.beginPath();
ctx.moveTo(25 + space + i * 50, 10);
ctx.lineTo(25 + space + i * 50, 140);
ctx.stroke();
});
ctx.lineWidth = 1;
this.drawDashedLine([], ctx);
this.drawDashedLine([2, 2], ctx);
this.drawDashedLine([10, 10], ctx);
this.drawDashedLine([20, 5], ctx);
this.drawDashedLine([15, 3, 3, 3], ctx);
this.drawDashedLine([20, 3, 3, 3, 3, 3, 3, 3], ctx);
ctx.lineDashOffset = 18;
this.drawDashedLine([12, 3, 3], ctx);
ctx.lineDashOffset = 0
ctx.setLineDash([0])
ctx.update()
},
drawDashedLine(pattern : Array<number>, ctx : DrawableContext) {
ctx.beginPath();
ctx.setLineDash(pattern);
ctx.moveTo(0, y);
ctx.lineTo(300, y);
ctx.stroke();
y += 15;
},
drawCircles() {
let ctx = uni.getElementById('draw-circle-view')!.getDrawableContext()!
ctx.reset()
// Draw shapes
for (var i = 0; i < 4; i++) {
for (var j = 0; j < 3; j++) {
ctx.beginPath();
var x = 25 + j * 50; // x coordinate
var y = 25 + i * 50; // y coordinate
var radius = 20; // Arc radius
var startAngle = 0; // Starting point on circle
var endAngle = Math.PI + (Math.PI * j) / 2; // End point on circle
var clockwise = i % 2 == 0 ? false : true; // clockwise or anticlockwise
ctx.arc(x, y, radius, startAngle, endAngle, clockwise);
if (i > 1) {
ctx.fill();
} else {
ctx.stroke();
}
}
}
ctx.update()
},
drawStar() {
let ctx = uni.getElementById('draw-dash-line')!.getDrawableContext()!
ctx.reset()
ctx.beginPath();
var horn = 5; // 画5个角
var angle = 360 / horn; // 五个角的度数
// 两个圆的半径
var R = 50;
var r = 20;
// 坐标
var x = 100;
var y = 100;
// #ifdef APP-HARMONY
//TODO 鸿蒙首次调用lineTo并不是起始点，这里暂时先调用一次moveTo
ctx.moveTo(Math.cos((18 + 0 * angle) / 180.0 * Math.PI) * R + x, -Math.sin((18 + 0 * angle) / 180.0 * Math.PI) * R + y);
// #endif
for (var i = 0; i < horn; i++) {
// 角度转弧度：角度/180*Math.PI
// 外圆顶点坐标
ctx.lineTo(Math.cos((18 + i * angle) / 180.0 * Math.PI) * R + x, -Math.sin((18 + i * angle) / 180.0 * Math.PI) * R + y);
// 內圆顶点坐标
ctx.lineTo(Math.cos((54 + i * angle) / 180.0 * Math.PI) * r + x, -Math.sin((54 + i * angle) / 180.0 * Math.PI) * r + y);
}
// closePath：关闭路径，将路径的终点与起点相连
ctx.closePath();
ctx.lineWidth = 3;
ctx.fillStyle = '#E4EF00';
ctx.strokeStyle = "red";
ctx.fill();
ctx.stroke();
ctx.lineWidth = 10;
ctx.beginPath()
ctx.moveTo(170, 100)
ctx.lineTo(255, 15)
ctx.lineTo(340, 100)
ctx.closePath()
ctx.fill()
ctx.strokeStyle = "blue"
ctx.stroke()
ctx.beginPath()
ctx.moveTo(170, 145)
ctx.lineTo(255, 45)
ctx.lineTo(340, 145)
ctx.closePath()
ctx.fill()
ctx.strokeStyle = "gray"
ctx.stroke()
// 未设置beginPath，导致上下表现一致，与前端一致
ctx.moveTo(170, 190)
ctx.lineTo(255, 90)
ctx.lineTo(340, 190)
ctx.closePath()
ctx.fillStyle = "orange"
ctx.fill()
ctx.strokeStyle = "khaki"
ctx.stroke()
ctx.update()
},
hex(num : number) : string {
if (num == 0) {
return "00"
}
let hexChars = "0123456789ABCDEF";
let result = "";
while (num > 0) {
let remainder = Math.floor(num) % 16;
result = hexChars[remainder] + result;
num = Math.floor(Math.floor(num) / 16);
}
if (result.length == 1) {
return "0" + result
}
return result
},
drawhouse() {
let ctx = uni.getElementById('draw-house')!.getDrawableContext()!
ctx.reset()
ctx.lineWidth = 10;
// Wall
ctx.strokeRect(75, 140, 150, 110);
// Door
ctx.fillRect(130, 190, 40, 60);
// Roof
ctx.beginPath();
ctx.moveTo(50, 140);
ctx.lineTo(150, 60);
ctx.lineTo(250, 140);
ctx.closePath();
ctx.stroke();
ctx.update()
},
drawPoint() {
let ctx = uni.getElementById('draw-style')!.getDrawableContext()!
ctx.reset()
for (let i = 0; i < 6; i++) {
for (let j = 0; j < 6; j++) {
ctx.strokeStyle = `rgb(0,${Math.floor(255 - 42.5 * i)},${Math.floor(255 - 42.5 * j)})`;
ctx.beginPath();
ctx.arc(12.5 + j * 25, 12.5 + i * 25, 10, 0, Math.PI * 2, true);
ctx.stroke();
}
}
for (let i = 0; i < 6; i++) {
for (let j = 0; j < 6; j++) {
ctx.fillStyle = `rgb(${Math.floor(255 - 42.5 * i)},${Math.floor(255 - 42.5 * j)},0)`;
ctx.fillRect(180 + j * 25, i * 25, 25, 25);
}
}
ctx.update()
},
drawRect() {
let ctx = uni.getElementById('draw-odd')!.getDrawableContext()!
ctx.reset()
// Create path
ctx.moveTo(30, 90);
ctx.lineTo(110, 20);
ctx.lineTo(240, 130);
ctx.lineTo(60, 130);
ctx.lineTo(190, 20);
ctx.lineTo(270, 90);
ctx.closePath();
// Fill path
ctx.fillStyle = "green";
ctx.fill("evenodd");
ctx.update()
},
drawArcTo() {
let ctx = uni.getElementById('draw-arcto')!.getDrawableContext()!
ctx.reset()
ctx.beginPath();
ctx.moveTo(50, 20);
ctx.bezierCurveTo(230, 30, 150, 60, 50, 100);
ctx.stroke();
ctx.fillStyle = "blue";
// start point
ctx.fillRect(50, 20, 10, 10);
// end point
ctx.fillRect(50, 100, 10, 10);
ctx.fillStyle = "red";
// control point one
ctx.fillRect(230, 30, 10, 10);
// control point two
ctx.fillRect(150, 70, 10, 10);
ctx.update()
}
}
}
</script>
<style>
.drawing {
height: 275px;
background-color: lightgray;
margin-bottom: 15px;
}
</style>
