Implement image cropping and saving functions in WeChat mini programs

Implementing the picture cropping and saving function in WeChat mini programs

Mini programs have gradually become an indispensable part of people’s lives. In the process of using mini programs, we , we often encounter situations where pictures need to be cropped. This article will introduce how to realize the function of cropping and saving pictures in WeChat applet.

1. Analyze requirements
Before starting development, we first need to clarify our requirements, which is to implement the image cropping function and save the cropped images. Specifically, the functions we need to implement are:

1. Select a picture for cropping;
2. Implement the drag, zoom and rotate functions of the picture;
3. Crop the picture according to the position and size of the cropping frame;
4. Save the cropped picture to the mobile phone album.

2. Implementation steps

1. Create a new mini program page. The structure of the page includes a cropping area and some control buttons. The style and layout of the page can be based on the actual situation. Need to be adjusted.

<view class="container">
  <image class="image" src="{{imageSrc}}"></image>
  <movable-area class="crop-area" scale="{{scale}}" rotate="{{rotate}}">
    <movable-view class="crop-image" direction="{{direction}}">
      <image src="{{imageSrc}}" mode="aspectFit"></image>
    </movable-view>
  </movable-area>
  <button class="btn" bindtap="chooseImage">选择图片</button>
  <button class="btn" bindtap="cropImage">裁剪图片</button>
  <button class="btn" bindtap="saveImage">保存图片</button>
</view>

2. In the logical part of the page, we need to implement the functions of selecting pictures, cropping pictures and saving pictures.

Page({
  data: {
    imageSrc: '',
    scale: 1,
    rotate: 0,
    direction: 0
  },

  chooseImage() {
    wx.chooseImage({
      success: res => {
        this.setData({
          imageSrc: res.tempFilePaths[0]
        });
      }
    });
  },

  cropImage() {
    // 根据裁剪框的位置和大小裁剪图片
    // ...
  },

  saveImage() {
    // 保存裁剪后的图片到手机相册
    // ...
  }
});

3. In the cropping function, we can use the movable-view component provided by the applet to realize the dragging, scaling and rotating functions of the image. By adjusting the position and size of the cropping box, Crop the picture.

<movable-view class="crop-image" direction="{{direction}}">
  <image src="{{imageSrc}}" mode="aspectFit"></image>
</movable-view>

In the cropping function, we can adjust the style of the cropping box to achieve different cropping effects.

4. In the picture saving function, we can use the saveImageToPhotosAlbum interface provided by the mini program to save the cropped picture to the mobile phone album.

saveImage() {
  wx.saveImageToPhotosAlbum({
    filePath: this.data.imageSrc,
    success: res => {
      wx.showToast({
        title: '保存成功',
        icon: 'success'
      });
    },
    fail: err => {
      wx.showToast({
        title: '保存失败',
        icon: 'none'
      });
    }
  });
}

The above are the basic steps and code examples to implement the image cropping and saving function in the WeChat applet. Developers can adjust and expand according to actual needs to achieve more functions and effects. I hope this article can be helpful to everyone!

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