如何实现微信小程序图片选择区域裁剪（微信小程序的裁剪图片功能）

如何实现微信小程序图片选择区域裁剪（微信小程序的裁剪图片功能）

本篇文章主要介绍了微信小程序图片选择区域屏裁剪实现方法，内容挺不错的，现在分享给大家，也给大家做个参考。

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

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HTML代码

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'　　//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

红框根据手指移动方法

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,官方正在修复不知道什么时候好

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