This article mainly introduces Vue to realize the functions of cropping pictures and enlarging, reducing and rotating images at the same time. The editor thinks it is quite good. Now I will share it with you and give you a reference. I hope it can help you.
Achieve the effect:
Crop the picture in the specified area
Rotate the picture
Enlarge the picture
The output bolb format data is provided to the formData object
Rendering
Use the h5 FileReader object to obtain "File uploaded to the browser". The file format is base64 format, and assign base64 to the canvas context.
Then add a (mousedown) listening event to the canvas element. When the user presses the left mouse button on the canvas:
dom.js
export const on = ({el, type, fn}) => {
if (typeof window) {
if (window.addEventListener) {
el.addEventListener(type, fn, false)
} else {
el.attachEvent(`on${type}`, fn)
}
}
}
export const off = ({el, type, fn}) => {
if (typeof window) {
if (window.addEventListener) {
el.removeEventListener(type, fn)
} else {
el.detachEvent(`on${type}`, fn)
}
}
}
export const once = ({el, type, fn}) => {
const hyFn = (event) => {
try {
fn(event)
}
finally {
off({el, type, fn: hyFn})
}
}
on({el, type, fn: hyFn})
}
// 最后一个
export const fbTwice = ({fn, time = 300}) => {
let [cTime, k] = [null, null]
// 获取当前时间
const getTime = () => new Date().getTime()
// 混合函数
const hyFn = () => {
const ags = argments
return () => {
clearTimeout(k)
k = cTime = null
fn(...ags)
}
}
return () => {
if (cTime == null) {
k = setTimeout(hyFn(...arguments), time)
cTime = getTime()
} else {
if ( getTime() - cTime < 0) {
// 清除之前的函数堆 ---- 重新记录
clearTimeout(k)
k = null
cTime = getTime()
k = setTimeout(hyFn(...arguments), time)
}
}}
}
export const contains = function(parentNode, childNode) {
if (parentNode.contains) {
return parentNode != childNode && parentNode.contains(childNode)
} else {
return !!(parentNode.compareDocumentPosition(childNode) & 16)
}
}
export const addClass = function (el, className) {
if (typeof el !== "object") {
console.log('el is not elem')
return null
}
let classList = el['className']
classList = classList === '' ? [] : classList.split(/\s+/)
if (classList.indexOf(className) === -1) {
classList.push(className)
el.className = classList.join(' ')
} else {
console.warn('warn className current')
}
}
export const removeClass = function (el, className) {
let classList = el['className']
classList = classList === '' ? [] : classList.split(/\s+/)
classList = classList.filter(item => {
return item !== className
})
el.className = classList.join(' ')
}
export const delay = ({fn, time}) => {
let oT = null
let k = null
return () => {
// 当前时间
let cT = new Date().getTime()
const fixFn = () => {
k = oT = null
fn()
}
if (k === null) {
oT = cT
k = setTimeout(fixFn, time)
return
}
if (cT - oT < time) {
oT = cT
clearTimeout(k)
k = setTimeout(fixFn, time)
}
}
}
export const Event = function () {
// 类型
this.typeList = {}
}
Event.prototype.on = function ({type, fn}){
if (this.typeList.hasOwnProperty(type)) {
this.typeList[type].push(fn)
} else {
this.typeList[type] = []
this.typeList[type].push(fn)
}
}
Event.prototype.off = function({type, fn}) {
if (this.typeList.hasOwnProperty(type)) {
let list = this.typeList[type]
let index = list.indexOf(fn)
if (index !== -1 ) {
list.splice(index, 1)
}
} else {
console.warn('not has this type')
}
}
Event.prototype.once = function ({type, fn}) {
const fixFn = () => {
fn()
this.off({type, fn: fixFn})
}
this.on({type, fn: fixFn})
}
Event.prototype.trigger = function (type){
if (this.typeList.hasOwnProperty(type)) {
this.typeList[type].forEach(fn => {
fn()
})
}
}Component template
<template>
<p class="jc-clip-image" :style="{width: `${clip.width}`}">
<canvas ref="ctx"
:width="clip.width"
:height="clip.height"
@mousedown="handleClip($event)"
>
</canvas>
<input type="file" ref="file" @change="readFileMsg($event)">
<p class="clip-scale-btn">
<a class="add" @click="handleScale(false)">+</a>
<a @click="rotate" class="right-rotate">转</a>
<a class="poor" @click="handleScale(true)">-</a>
<span>{{scale}}</span>
</p>
<p class="upload-warp">
<a class="upload-btn" @click="dispatchUpload($event)">upload</a>
<a class="upload-cancel">cancel</a>
</p>
<p class="create-canvas">
<a class="to-send-file" @click="outFile" title="请打开控制台">生成文件</a>
</p>
</p>
</template>
<script>
import {on, off, once} from '../../utils/dom'
export default {
ctx: null,
file: null,
x: 0, // 点击canvas x 鼠标地址
y: 0,// 点击canvas y 鼠标地址
xV: 0, // 鼠标移动 x距离
yV: 0, // 鼠标移动 y距离
nX: 0, // 原始坐标点 图像 x
nY: 0,// 原始坐标点 图像 y
img: null,
props: {
src: {
type: String,
default: null
},
clip: {
type: Object,
default () {
return {width: '200px', height: '200px'}
}
}
},
data () {
return {
isShow: false,
base64: null,
scale: 1.5, //放大比例
deg: 0 //旋转角度
}
},
computed: {
width () {
const {clip} = this
return parseFloat(clip.width.replace('px', ''))
},
height () {
const {clip} = this
return parseFloat(clip.height.replace('px', ''))
}
},
mounted () {
const {$options, $refs, width, height} = this
// 初始化 canvas file nX nY
Object.assign($options, {
ctx: $refs.ctx.getContext('2d'),
file: $refs.file,
nX: -width / 2,
nY: -height / 2
})
},
methods: {
// 旋转操作
rotate () {
const {$options, draw} = this
this.deg = (this.deg + Math.PI /2)% (Math.PI * 2)
draw($options.img, $options.nX + $options.xV, $options.nY + $options.yV, this.scale, this.deg)
},
// 处理放大
handleScale (flag) {
const {$options, draw, deg} = this
flag && this.scale > 0.1 && (this.scale = this.scale - 0.1)
!flag && this.scale < 1.9 && (this.scale = this.scale + 0.1)
$options.img && draw($options.img, $options.nX + $options.xV, $options.nY + $options.yV, this.scale, deg)
},
// 模拟file 点击事件
dispatchUpload (e) {
this.clearState()
const {file} = this.$options
e.preventDefault()
file.click()
},
// 读取 input file 信息
readFileMsg () {
const {file} = this.$options
const {draw, createImage, $options: {nX, nY}, scale, deg} = this
const wFile = file.files[0]
const reader = new FileReader()
reader.onload = (e) => {
const img = createImage(e.target.result, (img) => {
draw(img, nX, nY, scale, deg)
})
file.value = null
}
reader.readAsDataURL(wFile)
},
// 生成 图像
createImage (src, cb) {
const img = new Image()
this.$el.append(img)
img.className = 'base64-hidden'
img.onload = () => {
cb(img)
}
img.src = src
this.$options.img = img
},
// 操作画布画图
draw (img, x = 0, y = 0, scale = 0.5,deg = Math.PI ) {
const {ctx} = this.$options
let {width, height} = this
// 图片尺寸
let imgW = img.offsetWidth
let imgH = img.offsetHeight
ctx.save()
ctx.clearRect( 0, 0, width, height)
ctx.translate( width / 2, height / 2, img)
ctx.rotate(deg)
ctx.drawImage(img, x, y, imgW * scale, imgH * scale)
ctx.restore()
},
// ... 事件绑定
handleClip (e) {
const {handleMove, $options, deg} = this
if (!$options.img) {
return
}
Object.assign(this.$options, {
x: e.screenX,
y: e.screenY
})
on({
el: window,
type: 'mousemove',
fn: handleMove
})
once({
el: window,
type: 'mouseup',
fn: (e) =>{
console.log('down')
switch (deg) {
case 0: {
Object.assign($options, {
nX: $options.nX + $options.xV,
nY: $options.nY + $options.yV,
xV: 0,
yV: 0
})
break;
}
case Math.PI / 2: {
Object.assign($options, {
nX: $options.nY + $options.yV,
nY: $options.nX - $options.xV,
xV: 0,
yV: 0
})
break;
}
case Math.PI: {
Object.assign($options, {
nX: $options.nX - $options.xV,
nY: $options.nY - $options.yV,
xV: 0,
yV: 0
})
break;
}
default: {
// $options.nY - $options.yV, $options.nX + $options.xV
Object.assign($options, {
nX: $options.nY - $options.yV,
nY: $options.nX + $options.xV,
xV: 0,
yV: 0
})
}
}
off({
el: window,
type: 'mousemove',
fn: handleMove
})
}
})
},
// ... 处理鼠标移动
handleMove (e){
e.preventDefault()
e.stopPropagation()
const {$options, draw, scale, deg} = this
Object.assign($options, {
xV: e.screenX - $options.x,
yV: e.screenY - $options.y
})
switch (deg) {
case 0: {
draw($options.img, $options.nX + $options.xV, $options.nY + $options.yV, scale, deg)
break;
}
case Math.PI / 2: {
draw($options.img, $options.nY + $options.yV, $options.nX - $options.xV, scale, deg)
break;
}
case Math.PI: {
draw($options.img, $options.nX - $options.xV, $options.nY - $options.yV, scale, deg)
break;
}
default: {
draw($options.img, $options.nY - $options.yV, $options.nX + $options.xV, scale, deg)
break;
}
}
},
// 清除状态
clearState () {
const {$options, width, height} = this
if ($options.img) {
this.$el.removeChild($options.img)
Object.assign($options, {
x: 0,
y: 0,
xV: 0,
yV: 0,
nX: -width / 2,
nY: -height / 2,
img: null,
})
}
},
// 输出文件
outFile () {
const {$refs: {ctx}} = this
console.log(ctx.toDataURL())
ctx.toBlob((blob) => {console.log(blob)})
}
}
}
</script>
<style>
@component-namespace jc {
@component clip-image{
position: relative;
width: 100%;
canvas {
position: relative;
width: 100%;
height: 100%;
cursor: pointer;
box-shadow: 0 0 3px #333;
}
input {
display: none;
}
.base64-hidden {
position: absolute;
top: 0;
left: 0;
display: block;
width: 100%;
height: auto;
z-index: -999;
opacity: 0;
}
.clip-scale-btn {
position: relative;
@utils-clearfix;
margin-bottom: 5px;
text-align: center;
a {
float: left;
width: 20px;
height: 20px;
border-radius: 50%;
color: #fff;
background: #49a9ee;
text-align: center;
cursor: pointer;
}
&>.poor, &>.right-rotate {
float: right;
}
&>span{
position: absolute;
z-index: -9;
top: 0;
left: 0;
display: block;
position: relative;
width: 100%;
text-align: center;
height: 20px;
line-height: 20px;
}
}
.upload-warp {
@utils-clearfix;
.upload-btn,.upload-cancel {
float: left;
display:inline-block;
width: 60px;
height: 25px;
line-height: 25px;
color: #fff;
border-radius: 5px;
background: #49a9ee;
box-shadow: 0 0 0 #333;
text-align: center;
top: 0;
left: 0;
right: 0;
bottom: 0;
margin: auto;
cursor: pointer;
margin-top: 5px;
}
.upload-cancel{
background: gray;
float: right;
}
}
.to-send-file {
margin-top: 5px;
display: block;
width: 50px;
height: 25px;
line-height: 25px;
color: #fff;
border-radius: 5px;
background: #49a9ee;
cursor: pointer;
}
}The above is the detailed content of Vue cuts pictures to implement enlargement, reduction and rotation function code. For more information, please follow other related articles on the PHP Chinese website!
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