vue用canvas橫屏簽名

最近遇到一個簽名需求由于canvas一些特性，橫屏簽名不好控制，也是多方借鑒才解決，寫真就是為了記錄下，方便有需要的同學。
js代碼如下：

import Draw from "../../../libs/draw"; export default {name: "canvas",data() {return {degree: 0 // 屏幕整體旋轉(zhuǎn)的角度, 可取 -90,90,180等值};},components: {Draw},inject: ["reload"],mounted() {this.canvasBox = document.getElementById("canvasBox");this.initCanvas();var evt = "onorientationchange" in window ? "orientationchange" : "resize";var that = this;window.addEventListener(evt,function() {// alert(evt);setTimeout(function() {that.reload();}, 300);},false);},computed: {getHorizontalStyle() {const d = document;const w =window.innerWidth ||d.documentElement.clientWidth ||d.body.clientWidth;const h =window.innerHeight ||d.documentElement.clientHeight ||d.body.clientHeight;let length = (h - w) / 2;let width = w;let height = h;if (width < height) {this.degree = 90;width = h;height = w;} else {length = 0;}if (this.canvasBox) {this.canvasBox.removeChild(document.querySelector("canvas"));this.canvasBox.appendChild(document.createElement("canvas"));setTimeout(() => {this.initCanvas();}, 200);}return {transform: `rotate(${this.degree}deg) translate(${length}px,${length}px)`,width: `${width}px`,height: `${height}px`,transformOrigin: "center center"};}},methods: {initCanvas() {const canvas = document.querySelector("canvas");this.draw = new Draw(canvas, -this.degree);},clear() {this.draw.clear();},download() {const image = this.draw.getPNGImage();const blob = this.draw.dataURLtoBlob(image);const url = "";const successCallback = response => {console.log(response);};const failureCallback = error => {console.log(error);};this.draw.upload(blob, url, successCallback, failureCallback);}} };

html代碼：

<template><div id="canvasBox" :style="getHorizontalStyle"><canvas style="background-color:#fff;"></canvas><div class="greet"><div class="btnBox"><div class="btn" @click.native="clear()">重置</div><div class="btn" @click.native="download()" style="backgroundColor:#409EEF">確認</div></div></div></div> </template>

css部分

<style lang="less" scoped> #canvasBox {display: flex;flex-direction: column;height: 100%; } .greet {padding: 20px;font-size: 20px;user-select: none; } .greet a {cursor: pointer; } .greet select {font-size: 18px; } canvas {flex: 1;cursor: crosshair; } .btnBox {padding: 0 2%;box-sizing: border-box;.btn {text-align: center;color: #fff;background-color: #f91;height: 40px;line-height: 40px;font-weight: 300;font-size: 1em;border-radius: 4px;} } </style>

這個項目需要一個插件draw.js
畢竟不是app無法控制橫豎屏，所以本來是橫屏就直接簽名，豎屏旋轉(zhuǎn)。

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