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這篇文章將為大家詳細講解有關(guān)怎么利用vue組件實現(xiàn)圖片的拖拽和縮放功能,文章內(nèi)容質(zhì)量較高,因此小編分享給大家做個參考,希望大家閱讀完這篇文章后對相關(guān)知識有一定的了解。
vue實現(xiàn)一個組件其實很簡單但是要寫出一個好的可復用的組件那就需要多學習和鉆研一下,一個好的組件必須有其必不可少的有優(yōu)點:一是能提高應(yīng)用開發(fā)效率、測試性、復用性等;二是組件應(yīng)該是高內(nèi)聚、低耦合的;三是組件應(yīng)遵循單向數(shù)據(jù)流的原則。
在實現(xiàn)我的圖片的拖拽組件我們的搞清其原理,在這里我使用的是mousedown,mousemove和mouseup來實現(xiàn)拖拽。
1.新建ElementDrag.vue文件內(nèi)容如下:
<template> <div class="drag-outer" ref="dragWrap" @mousemove="dragMousemove"> <div class="drag-inner" ref="dragElement" @mousedown="dragMousedown" @mouseup.stop="isMousedown = false"> <slot></slot> </div> </div> </template>
2. 定義moveStart用于記錄拖拽元素初始位置。定義isMousedown變量來判斷鼠標是否按下, 如果isMousedown === true鼠標移動就改變darg-inner位置。
<script> export default { name: 'ElementDrag', data() { return { isMousedown: false, //鼠標是否按下 moveStart: {x: 0, y: 0}, //拖拽元素初始位置 translate: {x: 0, y: 0}, //計算拖拽元素在下下x,y方向各移動了多少 scale: 1, //拖拽元素縮放值 } }, methods: { dragMousedown() { this.moveStart.x = event.clientX this.moveStart.y = event.clientY this.isMousedown = true }, dragMousemove() { if(this.isMousedown) { this.translate.x += (event.clientX - this.moveStart.x) / this.scale this.translate.y += (event.clientY - this.moveStart.y) / this.scale this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` this.moveStart.x = event.clientX this.moveStart.y = event.clientY } } } } </script>
3.樣式部分我們設(shè)置外層drag-outer用flex布局讓里面元素快速居中, user-drag: none;禁用圖片等元素的可拖拽屬性。
<style lang="scss" scoped> .drag-outer { width: 100%; height: 100%; overflow: hidden; display: flex; justify-content: center; align-items: center; .drag-inner { transform-origin: center center; display: flex; justify-content: center; align-items: center; cursor: move; user-select: none; >* { -webkit-user-drag: none; user-drag: none; } } } </style>
4.添加鼠標滾輪事件縮放drag-inner元素, e.wheelDelta為正表示放大,為負縮小,值越大表示滾動越快。通過scale控制拖拽元素縮放。同過對組件傳值scaleZoom來控制其縮放最大最小程度值。
... methods: { props: { type: Object, default(){ return { min: 0.5, max: 5 } } }, ... handleScroll(e) { let speed = e.wheelDelta/120 if(e.wheelDelta > 0 && this.scale < this.scaleZoom.max) { this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` }else if(e.wheelDelta < 0 && this.scale > this.scaleZoom.min){ this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` } } }, mounted() { window.addEventListener('mousewheel',this.handleScroll,false) }
5.以上代碼已經(jīng)實現(xiàn)了功能我們預期的功能,但是為了更好的體驗,需要進一步優(yōu)化組件。添加isHover來控制鼠標是否移動到了drag-outer以外,如果isHover為false這時鼠標滾輪滾動不會縮放元素,并且將isMousedown設(shè)置為false。再使用插槽slot預覽位置。
<template> <div class="drag-outer" ref="dragWrap" @mouseenter="isHover = true" @mouseleave="isHover = isMousedown = false" @mousemove="dragMousemove"> <div class="drag-inner" ref="dragElement" @mousedown="dragMousedown" @mouseup.stop="isMousedown = false"> <slot></slot> </div> </div> </template> .... data() { return { ..., isHover: false, } }, methods: { ... handleScroll(e) { if(this.isHover) { let speed = e.wheelDelta/120 if(e.wheelDelta > 0 && this.scale < this.scaleZoom.max) { this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` }else if(e.wheelDelta < 0 && this.scale > this.scaleZoom.min){ this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` } } } }
貼上組件的最終代碼:
<template> <div class="drag-outer" ref="dragWrap" : @mouseenter="isHover = true" @mouseleave="isHover = isMousedown = false" @mousemove="dragMousemove"> <div class="drag-inner" ref="dragElement" : @mousedown="dragMousedown" @mouseup.stop="isMousedown = false"> <slot></slot> </div> </div> </template> <script> export default { name: 'ElementDrag', props: { outerOptions: { type: Object, default () { return { background: 'rgba(0,0,0,0.9)' } } }, innerOptions: { type: Object, default () { return { background: 'rgba(0,0,0,0.1)', } } }, scaleZoom: { type: Object, default () { return { max: 5, min: 0.2 } } } }, data() { return { isMousedown: false, isHover: false, moveStart: {}, translate: {x: 0, y: 0}, scale: 1 } }, methods: { handleScroll(e) { if(this.isHover) { let speed = e.wheelDelta/120 if(e.wheelDelta > 0 && this.scale < this.scaleZoom.max) { this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` }else if(e.wheelDelta < 0 && this.scale > this.scaleZoom.min){ this.scale+=0.04*speed this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` } } }, dragMousedown() { this.moveStart.x = event.clientX this.moveStart.y = event.clientY this.isMousedown = true }, dragMousemove() { if(this.isMousedown) { this.translate.x += (event.clientX - this.moveStart.x) / this.scale this.translate.y += (event.clientY - this.moveStart.y) / this.scale this.$refs.dragElement.style.transform = `scale(${this.scale}) translate(${this.translate.x}px, ${this.translate.y}px)` this.moveStart.x = event.clientX this.moveStart.y = event.clientY } } }, mounted() { window.addEventListener('mousewheel',this.handleScroll,false) } } </script> <style lang="scss" scoped> .drag-outer { width: 100%; height: 100%; overflow: hidden; display: flex; justify-content: center; align-items: center; .drag-inner { transform-origin: center center; display: flex; justify-content: center; align-items: center; cursor: move; user-select: none; >* { -webkit-user-drag: none; user-drag: none; } } } </style>
在home.vue文件使用:點擊體驗
<template> <div class="home"> <ElementDrag> <img src="https://img0.baidu.com/it/u=937276518,3474029246&fm=253&fmt=auto&app=138&f=JPEG?w=500&h=750"> </ElementDrag> </div> </template> <script> import ElementDrag from '@/components/ElementDrag' export default { name: 'Home', components: { ElementDrag } } </script> <style scoped> .home { width: 100vw; height: 100vh; } </style>
Vue是一款友好的、多用途且高性能的JavaScript框架,使用vue可以創(chuàng)建可維護性和可測試性更強的代碼庫,Vue允許可以將一個網(wǎng)頁分割成可復用的組件,每個組件都包含屬于自己的HTML、CSS、JavaScript,以用來渲染網(wǎng)頁中相應(yīng)的地方,所以越來越多的前端開發(fā)者使用vue。
關(guān)于怎么利用vue組件實現(xiàn)圖片的拖拽和縮放功能就分享到這里了,希望以上內(nèi)容可以對大家有一定的幫助,可以學到更多知識。如果覺得文章不錯,可以把它分享出去讓更多的人看到。
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