yarn install cropperjs

<canvas :id="data.src" ref="canvas"></canvas>

// 在canvas上繪制圖片drawImg () { this.$nextTick(() => { // 獲取canvas節點 let canvas = document.getElementById(this.data.src) if (canvas) { // 設置canvas的寬為canvas的父元素寬度，寬高比3:2 let parentEle = canvas.parentElement canvas.width = parentEle.offsetWidth canvas.height = 2 * parentEle.offsetWidth / 3 let ctx = canvas.getContext('2d') ctx.clearRect(0, 0, canvas.width, canvas.height) let img = new Image() img.crossOrigin = 'Anonymous' img.src = this.data.src img.onload = function () { ctx.drawImage(img, 0, 0, canvas.width, canvas.height) } } })}

// 引入import Cropper from 'cropperjs'// 顯示裁剪框initCropper () { let cropper = new Cropper(this.$refs.canvas, { checkCrossOrigin: true, viewMode: 2, aspectRatio: 3 / 2 })}

cropImg () { let canvas = document.getElementById(this.data.img_url) let ctx = canvas.getContext('2d') let img = new Image() img.onload = function () { ctx.drawImage(img, 0, 0, canvas.width, canvas.height) } img.src = this.data.src let drag = false // 是否拖動矩形 let flag = false // 是否繪制矩形 let rectWidth = 0 // 繪制矩形的寬 let rectHeight = 0 // 繪制矩形的高 let clickX = 0 // 矩形開始繪制X坐標 let clickY = 0 // 矩形開始繪制Y坐標 let dragX = 0 // 當要拖動矩形點擊時X坐標 let dragY = 0 // 當要拖動矩形點擊時Y坐標 let newRectX = 0 // 拖動變化后矩形開始繪制的X坐標 let newRectY = 0 // 拖動變化后矩形開始繪制的Y坐標 // 鼠標按下 canvas.onmousedown = e => { // 每次點擊前如果有繪制好的矩形框，通過路徑繪制出來，用于下面的判斷 ctx.beginPath() ctx.setLineDash([6, 6]) ctx.moveTo(newRectX, newRectY) ctx.lineTo(newRectX + rectWidth, newRectY) ctx.lineTo(newRectX + rectWidth, newRectY + rectHeight) ctx.lineTo(newRectX, newRectY + rectHeight) ctx.lineTo(newRectX, newRectY) ctx.strokeStyle = 'green' ctx.stroke() // 每次點擊，通過判斷鼠標點擊的點在矩形框內還是外，來決定重新繪制還是移動矩形框 if (ctx.isPointInPath(e.offsetX, e.offsetY)) { drag = true dragX = e.offsetX dragY = e.offsetY clickX = newRectX clickY = newRectY } else { ctx.clearRect(0, 0, canvas.width, canvas.height) ctx.drawImage(img, 0, 0, canvas.width, canvas.height) flag = true clickX = e.offsetX clickY = e.offsetY newRectX = e.offsetX newRectY = e.offsetY } } // 鼠標抬起 canvas.onmouseup = () => { if (flag) { flag = false this.sureCrop(clickX, clickY, rectWidth, rectHeight) } if (drag) { drag = false this.sureCrop(newRectX, newRectY, rectWidth, rectHeight) } } // 鼠標移動 canvas.onmousemove = (e) => { if (flag) { ctx.clearRect(0, 0, canvas.width, canvas.height) ctx.drawImage(img, 0, 0, canvas.width, canvas.height) rectWidth = e.offsetX - clickX rectHeight = e.offsetY - clickY ctx.beginPath() ctx.strokeStyle = '#FF0000' ctx.strokeRect(clickX, clickY, rectWidth, rectHeight) ctx.closePath() } if (drag) { ctx.clearRect(0, 0, canvas.width, canvas.height) ctx.drawImage(img, 0, 0, canvas.width, canvas.height) ctx.beginPath() newRectX = clickX + e.offsetX - dragX newRectY = clickY + e.offsetY - dragY ctx.strokeStyle = 'yellow' ctx.strokeRect(newRectX, newRectY, rectWidth, rectHeight) ctx.closePath() } }},// 拿到裁剪后的參數，可自行處理圖片sureCrop (x, y, width, height) { let canvas = document.getElementById(this.data.img_url + 'after') // 設置canvas的寬為canvas的父元素寬度，寬高比3:2 let parentEle = canvas.parentElement canvas.width = parentEle.offsetWidth canvas.height = 2 * parentEle.offsetWidth / 3 let ctx = canvas.getContext('2d') let img = new Image() img.src = this.data.src img.onload = function () { ctx.beginPath() ctx.moveTo(x, y) ctx.lineTo(x + width, y) ctx.lineTo(x + width, y + height) ctx.lineTo(x, y + height) ctx.clip() ctx.drawImage(img, 0, 0, canvas.width, canvas.height) } ctx.stroke()}