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这篇文章将为大家详细讲解有关微信小程序图片选择区域实现裁剪功能方法教程,小编觉得挺实用的,因此分享给大家做个参考,希望大家阅读完这篇文章后可以有所收获。
效果图
HTML代码
<view class="index_all_box"> <view class="imgCut_header"> <view class="imgCut_header_l" bindtap='okCutImg'>开始裁剪</view> <view class="imgCut_header_m" bindtap='clickUpImg'>点击上传图片</view> <view class="imgCut_header_r" bindtap='okBtn'>点击确认</view> </view> <!-- 选择裁剪模式 --> <view class="selectCutMode" wx:if='{{alreay}}'> <view class="selectCutMode_in {{cutType?'selectCutMode_in_act':''}}" bindtap='etcType'> 等屏裁剪 </view> <view class="selectCutMode_in {{!cutType?'selectCutMode_in_act':''}}" bindtap='areaType'> 区域裁剪 </view> </view> <view class="areaSelct_box" wx:if='{{!cutType && alreay}}'> <slider bindchange="areaChange" min="50" max="100" show-value value='{{propor}}'/> </view> <view class="cutImg_box" wx:if='{{!prienFlag}}'> <view class="cutImg_box_t"> <image src="{{cutImgUrl}}" mode='widthFix'></image> </view> <view class="clickCutImg_txt" bindtap='againBtn'>重新裁剪</view> </view> <view class="allCavans" wx:if='{{prienFlag}}' style='width: {{canvasW}}px;height: {{canvasH}}px' > <canvas class='canvasSty' style='width: {{canvasW}}px;height: {{canvasH}}px' canvas-id='cutImg' disable-scroll='true' bindtouchmove='canvasMove'></canvas> <view class="allCavans_inbg" style='width: {{canvasW}}px;height:{{canvasH}}px; background: url({{img}});background-size: 100% 100%'></view> </view> </view>
CSS代码
.imgCut_header{ padding: 30rpx; display: flex; justify-content: space-between; align-items: center; background: #000; color: #fff; font-size: 24rpx; } .allCavans{ margin: 20rpx auto; position: relative; } .canvasSty{ position: absolute; } .cutImg_box{ width: 100%; border-bottom: 2rpx #f98700 solid; padding-bottom: 20rpx; } .cutImg_box .cutImg_box_t{ width: 90%; margin: 20rpx auto; } .cutImg_box image{ width: 100%; } .cutImg_box .cutImg_box_b{ margin-top: 20rpx; width: 80%; height: 80rpx; line-height: 80rpx; background: #f98700; color: #fff; border-radius: 10rpx; text-align: center; margin:0rpx auto; } .selectCutMode{ background: #fff; display: flex; justify-content: space-between; align-items: center; } .selectCutMode .selectCutMode_in{ width: 100%; text-align: center; background: #fff; color: #f98700; font-size: 24rpx; padding: 20rpx; } .selectCutMode .selectCutMode_in_act{ background: #f98700; color: #fff; padding: 20rpx; } .areaSelct_box{ width: 100%; display: flex; align-items: center; height: 50rpx; justify-content: center; margin-top: 20rpx; } .areaSelct_box slider{ width: 80%; } .cutImg_box .clickCutImg_txt{ width: 100%; text-align: center; height: 50rpx; font-size: 24rpx; line-height: 50rpx; color: #999; }
JS代码部分
初始加载带入上一个页面带过来的参数路径
onLoad: function (options) { var that = this; const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) var aa = 'https://pintuanqu.oss-cn-hangzhou.aliyuncs.com/Uploads/Picture/goodsShow/20171201/5a2125fc86566.png'<br /> //获取当前屏幕宽度 var phoneW = Number(util.nowPhoneWH()[0]*90)/100; var cutH = 150; wx.getImageInfo({ src: aa, success: function (res) { var w = phoneW; var h = (phoneW/Number(res.width))*Number(res.height) ctx.save() ctx.drawImage(aa, 0, 0, w, h) ctx.restore() ctx.setFillStyle('red') ctx.fillRect(0, 0, phoneW, cutH) ctx.draw() that.setData({ canvasW:w, canvasH:h, img:aa, cutH:cutH }) } }) },
确定选择区域开始裁剪
// 点击确认裁剪图片 okCutImg:function(){ var that = this; var canvasW = that.data.canvasW; var canvasH = that.data.canvasH; var nowCutW = that.data.cutType?canvasW:that.data.nowCutW; var nowCutH = that.data.cutType?that.data.cutH:that.data.nowCutH; var cutX = that.data.cutX; var cutY = that.data.cutY; const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(1) ctx.drawImage(that.data.img, 0, 0, canvasW, canvasH) ctx.draw() wx.canvasToTempFilePath({ x: cutX, y: cutY, width: nowCutW, height: nowCutH, destWidth: nowCutW, destHeight: nowCutH, canvasId: 'cutImg', success: function(res) { var aa = res.tempFilePath that.setData({ cutImgUrl:aa, prienFlag:false, alreay:false }) } }) },
红框根据手指移动方法
// 点击红框开始移动 canvasMove:function(e){ var that = this; var canvasW = that.data.canvasW; var canvasH = that.data.canvasH; var nowCutW = that.data.cutType?canvasW:that.data.nowCutW; var nowCutH = that.data.cutType?that.data.cutH:that.data.nowCutH var touches = e.touches[0]; var x = touches.x; var y = touches.y-(Number(nowCutH)/2); that.data.cutType?x=0:x=x-(Number(nowCutW)/2); that.setData({ cutX:x, cutY:y }) const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) ctx.drawImage(that.data.img, 0, 0, canvasW, canvasH) ctx.setFillStyle('red') ctx.fillRect(x, y, nowCutW, nowCutH) ctx.draw() },
上方两个选择裁剪方式的按钮
等屏裁剪
//等屏裁剪 etcType:function(){ var that = this; var propor = 100; var canvasW = that.data.canvasW; var canvasH = that.data.canvasH; var cutH = that.data.cutH; var nowCutW = (Number(canvasW)*propor)/100 var nowCutH = (Number(cutH)*propor)/100 const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) ctx.drawImage(that.data.img, 0, 0, canvasW, canvasH) ctx.setFillStyle('red') ctx.fillRect(0, 0, nowCutW, nowCutH) ctx.draw() that.setData({ nowCutW:nowCutW, nowCutH:nowCutH, cutType:true }) },
局域裁剪
areaType:function(){ var that = this; var propor = that.data.propor; var canvasW = that.data.canvasW; var canvasH = that.data.canvasH; var cutH = that.data.cutH; var nowCutW = (Number(canvasW)*propor)/100 var nowCutH = (Number(cutH)*propor)/100 const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) ctx.drawImage(that.data.img, 0, 0, canvasW, canvasH) ctx.setFillStyle('red') ctx.fillRect(0,0, nowCutW, nowCutH) ctx.draw() that.setData({ nowCutW:nowCutW, nowCutH:nowCutH, cutType:false }) },
局域裁剪上方的滑动选择红框根据宽度等比例缩放
areaChange:function(e){ var that = this; var propor = e.detail.value; var canvasW = that.data.canvasW; var canvasH = that.data.canvasH; var cutH = that.data.cutH; var nowCutW = (Number(canvasW)*propor)/100 var nowCutH = (Number(cutH)*propor)/100 const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) ctx.drawImage(that.data.img, 0, 0, canvasW, canvasH) ctx.setFillStyle('red') ctx.fillRect(that.data.cutX||0, that.data.cutY||0,nowCutW, nowCutH) ctx.draw() that.setData({ nowCutW:nowCutW, nowCutH:nowCutH, propor:propor }) },
重新裁剪回到初始选择图片的页面
// 重新裁剪 againBtn:function(){ var that = this; var data = that.data this.setData({ prienFlag:true, alreay:true }) const ctx = wx.createCanvasContext('cutImg'); ctx.setGlobalAlpha(0.4) ctx.drawImage(data.img, 0, 0, data.canvasW, data.canvasH) ctx.setFillStyle('red') ctx.fillRect(that.data.cutX||0, that.data.cutY||0, data.nowCutW||data.canvasW, data.nowCutH||data.cutH) ctx.draw() },
现在IOS还有个坑就是裁剪不了,官方正在修复中。
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