本文介绍了微信小程序图片选择区域屏裁剪实现方法,分享给大家。具体如下:
效果图
<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
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 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,官方正在修复不知道什么时候好