<view class="cut-1-1 t-c {{cutSelect == 1" data-cut="1" bindtap="selectCutType">1:1</view>
<view class="cut-3-4 t-c {{cutSelect == 2" data-cut="2" bindtap="selectCutType">3:4</view>

<block wx:for="{{imgList}}" wx:key="{{index}}" >
  <swiper-item>
  <scroll-view scroll-top="{{topNum}}" scroll-y class="imgFile {{cutSelect == 1" bindscroll="endTou">
   <image src='{{item}}' mode="widthFix"></image>
  </scroll-view >
  </swiper-item>
</block>

<canvas wx:for="{{imgList}}" wx:for-index="i" canvas-id="myCanvas_{{i}}" style="width: {{width[i]"></canvas>

.view-1-1 {
 width: 750rpx;
 height: 750rpx;
 overflow: hidden;
}

.view-3-4 {
 width: 750rpx;
 height: 750rpx;
 padding: 0 94rpx;
 box-sizing: border-box;
 overflow: hidden;
}

canvas {
 position: absolute;
 /* display: none; */
 left: -999rpx;
 z-index: 0;
}

cutPic() {
 const _this = this
 if (this.data.cutting) {
  return
 }
 let promiseList = [], ctx = []
 _this.data.imgList.forEach((v, i) => {
  promiseList.push(_this.draw(ctx, v, i))
 })
 wx.showLoading({
  title: '截取中...',
  icon: 'none'
 })
 this.setData({
  cutting: true
 })
 Promise.all(promiseList).then((arr) => {
  wx.setStorageSync("interimImagesList", _this.data.imgFileList)
  _this.uploadPic()
 }, err => {
 })
 },

//获取竖向滑动坐标
 endTou(e) {
 const _this = this
 let y = 'y[' + (_this.data.currentIndex - 1) + '].top'
 _this.setData({
  [y]: e.detail.scrollTop
 })
 },

//绘制
 draw(ctx, v, i) {
 const _this = this
 let width, height
 return new Promise((resolve, reject) => {
  ctx[i] = wx.createCanvasContext(`myCanvas_${i}`)
  wx.getImageInfo({
  src: v,
  success: function (res) {
   width = 'width[' + i + ']'
   height = 'height[' + i + ']'
   var str = res.height / res.width;//图片的宽高比
   _this.setData({
   [width]: 375,
   [height]: 375 * str
   }, () => {
   ctx[i].drawImage(v, 0, 0, _this.data.width[i], _this.data.height[i])
   ctx[i].draw(false, () => {
    setTimeout(() => {
    wx.canvasToTempFilePath({//调用方法，开始截取
     x: 0,
     y: _this.data.y[i] "color: #ff0000">总结


一个简单的canvas截图就制作完成了。值得注意的是canvas渲染是需要时间的。

这也算是一个简单的练手吧，下次有什么复杂的截图功能再分享出来吧。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。