微信小程序實現(xiàn)裁剪圖片大小

更新時間：2022年05月23日 17:12:55 作者：換日線°

這篇文章主要為大家詳細介紹了微信小程序實現(xiàn)裁剪圖片大小，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了微信小程序實現(xiàn)裁剪圖片大小的具體代碼，供大家參考，具體內容如下

效果圖

.wxml

<button bindtap="uploadtap">上傳圖片</button>
<image style="width: 100%;" mode="widthFix" src="{{canfile_image}}"></image>
<canvas canvas-id="myCanvas" id="myCanvas" style="width:100%;height:70vh;"></canvas>
<view class="canvas_model" wx:if="{{canvas_arr.show}}" catchtouchmove="setTouchMove">
? <view class="canvas_view" style="width: {{canvas_arr.width}}px;height: {{canvas_arr.height}}px;"
? bindtouchstart="handletouchstart" bindtouchmove="handletouchmove">
? ? <image style="width:100%;height:100%;" src="{{canvas_arr.src}}"></image>
? ? <view style="{{color_status?'background: rgba(0, 0, 0, 0.6);':''}}">
? ? ? <view class="canvas_horn" style="height:{{cutting.height}}px;top:{{canvas_y}}px;">
? ? ? ? <view></view>
? ? ? ? <view></view>
? ? ? ? <view></view>
? ? ? ? <view></view>
? ? ? ? <view></view>
? ? ? ? <view></view>
? ? ? ? <image style="width: {{canvas_arr.width}}px;height: {{canvas_arr.height}}px;top:-{{canvas_y}}px;" src="{{canvas_arr.src}}"></image>
? ? ? </view>
? ? </view>
? </view>
? <view class="canvas_bar" wx:if="{{cutting.show}}">
? ? <view bindtap="color_tap">×</view>
? ? <view class="bar_tab {{color_status?'tab_cation':''}}" bindtap="color_tap" data-type="1">
? ? ? <view>淺色</view>
? ? ? <view>深色</view>
? ? ? <view></view>
? ? </view>
? ? <view bindtap="ationimg">√</view>
? </view>
</view>

.wxss

?.canvas_model{width: 100%;height: 100vh;position: fixed;left: 0;top: 0;background: rgba(0, 0, 0, 0.6);z-index: 10;
display:flex;justify-content: center;padding-top: 10vh;animation:model 0.3s;}
@keyframes model{
? from { opacity: 0;transform: scale(0.5); }
? to { opacity:1;transform: scale(1); }
}
.canvas_view{float: left;position: relative;}
.canvas_view>view{width: 100%;height: 100%;position: absolute;left: 0;top: 0;background: rgba(255, 255, 255, 0.4);transition: all 0.3s;}
.canvas_horn{position: absolute;left: 0;width: 100%;overflow: hidden;}
.canvas_horn>view{width: 40rpx;height: 40rpx;position: absolute;z-index: 1;}
.canvas_horn>image{position: absolute;left: 0;top: 0;}
.canvas_horn>view:nth-child(1){border-left: 2px solid #fff;border-top: 2px solid #fff;left: 0;top: 0;}
.canvas_horn>view:nth-child(2){border-right: 2px solid #fff;border-top: 2px solid #fff;right: 0;top: 0;}
.canvas_horn>view:nth-child(3){border-left: 2px solid #fff;border-bottom:2px solid #fff;left: 0;bottom: 0;}
.canvas_horn>view:nth-child(4){border-right: 2px solid #fff;border-bottom: 2px solid #fff;right: 0;bottom: 0;}
.canvas_horn>view:nth-child(5){width: 60rpx;height: 2px;background: #fff;top: 0;left: 0;right: 0;margin: 0 auto;}
.canvas_horn>view:nth-child(6){width: 60rpx;height: 2px;background: #fff;bottom: 0;left: 0;right: 0;margin: 0 auto;}
.canvas_bar{width: 100%;height: 14vh;display: flex;align-items: center;justify-content: space-between;background: #fff;
position: absolute;left: 0;bottom: 0;animation:bartion 0.5s;}
@keyframes bartion{
? from { bottom: -14vh; }
? to { bottom: 0; }
}
.canvas_bar>view:nth-child(1),.canvas_bar>view:nth-child(3){width: 160rpx;height: 100%;display: flex;align-items: center;
justify-content: center;font-size: 44rpx;font-weight: 700;}
.bar_tab{width: 300rpx;display: flex;height: 60rpx;border-radius: 10rpx;border: 1px solid #f4f4f4;line-height: 60rpx;
position: relative;font-size: 24rpx;color: #333;}
.bar_tab>view{width: 50%;height: 100%;text-align: center;position: relative;z-index: 1;transition: all 0.3s;}
.bar_tab>view:nth-child(1){color: #fff;}
.bar_tab>view:nth-child(3){position: absolute;left: 0;top: 0;background: #0081ff;border-radius: 10rpx;z-index: 0;}
.tab_cation>view:nth-child(1){color: #000;}
.tab_cation>view:nth-child(2){color: #fff;}
.tab_cation>view:nth-child(3){left: 50%;}
#myCanvas{position: absolute;left: 0;top: -71vh;z-index: -1;opacity: 0;}

.js

Page({
? data: {
? ? canvas_arr:{
? ? ? src:'',
? ? ? width:parseInt(wx.getSystemInfoSync().windowWidth * 0.9),
? ? ? height:parseInt(wx.getSystemInfoSync().windowHeight * 0.7),
? ? ? show:false
? ? },
? ? cutting:{
? ? ? height:0,
? ? ? max_y:0,
? ? ? show:false
? ? },
? ? canvas_y:0,
? ? color_status:false,
? ? canfile_image:'',
? },
? color_tap(e){
? ? var type = e?e.currentTarget.dataset.type:0
? ? if(type == 1){
? ? ? this.setData({
? ? ? ? color_status:!this.data.color_status
? ? ? })
? ? }else{
? ? ? this.data.canvas_arr.show = false
? ? ? this.data.canvas_arr.height = parseInt(wx.getSystemInfoSync().windowHeight * 0.7)
? ? ? this.data.cutting.show = false
? ? ? this.data.cutting.src = ''
? ? ? this.setData({
? ? ? ? canvas_arr:this.data.canvas_arr,
? ? ? ? cutting:this.data.cutting,
? ? ? ? canvas_y:0,
? ? ? })
? ? }
? },
? setTouchMove(e){return;},
? uploadtap(e){
? ? var that = this
? ? wx.chooseImage({
? ? ? count:1,
? ? ? success (res) {
? ? ? ? const tempFilePaths = res.tempFilePaths[0]
? ? ? ? that.data.canvas_arr.src = tempFilePaths
? ? ? ? wx.getImageInfo({
? ? ? ? ? src: tempFilePaths,
? ? ? ? ? success (res) {
? ? ? ? ? ? that.data.canvas_arr.show = true
? ? ? ? ? ? that.data.cutting.show = true
? ? ? ? ? ? that.data.cutting.height = that.data.canvas_arr.width / 2
? ? ? ? ? ? var height = parseInt(res.height / (res.width / that.data.canvas_arr.width))
? ? ? ? ? ? that.data.canvas_arr.height = height > that.data.canvas_arr.height ? that.data.canvas_arr.height : height
? ? ? ? ? ? that.data.cutting.max_y = that.data.canvas_arr.height - that.data.cutting.height
? ? ? ? ? ? that.setData({
? ? ? ? ? ? ? canvas_arr:that.data.canvas_arr
? ? ? ? ? ? })
? ? ? ? ? ? setTimeout(function () {
? ? ? ? ? ? ? that.setData({
? ? ? ? ? ? ? ? cutting:that.data.cutting
? ? ? ? ? ? ? })
? ? ? ? ? ? },500)
? ? ? ? ? }
? ? ? ? })
? ? ? }
? ? })
? },
? handletouchstart: function (e) {
? ? this.data.startY = e.touches[0].clientY
? },
? handletouchmove (e) {
? ? let currentY = e.touches[0].clientY - this.data.startY
? ? if(currentY > 0){
? ? ? this.setData({
? ? ? ? canvas_y:currentY > this.data.cutting.max_y?this.data.cutting.max_y:currentY,
? ? ? })
? ? }else{
? ? ? this.setData({
? ? ? ? canvas_y:0
? ? ? })
? ? }
? },
? ationimg(e){
? ? var that = this
? ? var canvas_img = wx.createCanvasContext('myCanvas')
? ? canvas_img.width = that.data.canvas_arr.width
? ? canvas_img.height = that.data.canvas_arr.height
? ? canvas_img.drawImage(that.data.canvas_arr.src,0,0,canvas_img.width,canvas_img.height)
? ? canvas_img.draw(true,(()=>{
? ? ? wx.canvasToTempFilePath({
? ? ? ? x: 0,
? ? ? ? y: that.data.canvas_y,
? ? ? ? width:that.data.canvas_arr.width,
? ? ? ? height:that.data.cutting.height,
? ? ? ? canvasId: 'myCanvas',
? ? ? ? success: function (res) {
? ? ? ? ? that.setData({
? ? ? ? ? ? canfile_image:res.tempFilePath
? ? ? ? ? })
? ? ? ? ? that.color_tap()
? ? ? ? ? wx.showToast({
? ? ? ? ? ? title: '裁剪成功~',
? ? ? ? ? ? icon: 'none',
? ? ? ? ? ? duration: 3000
? ? ? ? ? })
? ? ? ? }
? ? ? });
? ? }))
? },
})

功能主要針對輪播圖片尺寸，不合適可自行修改比例

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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