uniapp implements how to use the image cropping and compression library to implement image processing functions

uniapp implements how to use image cropping and compression libraries to implement image processing functions

When developing mobile applications, image processing requirements are often involved, such as image cropping and compression. In response to these needs, uniapp provides a wealth of plug-ins and components, allowing developers to easily implement image processing functions. This article will introduce how to use the image cropping and compression library in uniapp to implement image processing functions, and provide corresponding code examples.

1. Picture cropping

Picture cropping refers to cutting out a part of the picture as needed. The commonly used image cropping plug-in in uniapp is "uniCropper". The following is a code example for using uniCropper to implement image cropping:

<template>
  <view>
    <image :src="imageSrc" mode="aspectFit" @tap="chooseImage"></image>
    <uni-cropper
      ref="cropper"
      :src="imageSrc"
      :styleType="styleType"
      :aspectRatio="aspectRatio"
      :minCropBoxWidth="minCropBoxWidth"
      :minCropBoxHeight="minCropBoxHeight"
      :maxCropBoxWidth="maxCropBoxWidth"
      :maxCropBoxHeight="maxCropBoxHeight"
      @ready="ready"
      @crop="crop"
    ></uni-cropper>
    <button @click="cropImage">裁剪</button>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        imageSrc: '',
        styleType: 1,
        aspectRatio: 1,
        minCropBoxWidth: 50,
        minCropBoxHeight: 50,
        maxCropBoxWidth: 200,
        maxCropBoxHeight: 200
      };
    },
    methods: {
      chooseImage() {
        uni.chooseImage({
          success: (res) => {
            this.imageSrc = res.tempFilePaths[0];
          }
        });
      },
      ready() {
        this.$refs.cropper.setDragMode('crop');
      },
      crop(e) {
        console.log('裁剪结果：', e.detail);
      },
      cropImage() {
        this.$refs.cropper.crop();
      }
    }
  };
</script>

In the above code example, the "uniCropper" component is first introduced and the "uni-cropper" tag is used in the template tag. By clicking the "chooseImage" method, you can select an image, and the selected image will be displayed in the image tag. Next, by specifying various attributes of the uni-cropper tag, the configuration of the cropping frame is achieved. After clicking the crop button, the cropImage method will be triggered, the $refs.cropper.crop() method will be called to perform cropping, and the cropping result will be obtained through the crop method.

2. Image Compression

Image compression refers to saving storage space and improving network transmission speed by reducing the file size of images. The commonly used image compression plug-in in uniapp is "uni.compressImage". The following is a code example that uses uni.compressImage to implement image compression:

//选择图片并压缩
uni.chooseImage({
  success: (res) => {
    let tempFilePath = res.tempFilePaths[0];
    uni.compressImage({
      src: tempFilePath,
      quality: 80,   // 压缩质量，取值范围为0-100
      success: (res) => {
        let compressedFilePath = res.tempFilePath;
        // 在这里可以处理压缩后的图片
        console.log(compressedFilePath);
      }
    });
  }
});

In the above code example, an image is selected through the uni.chooseImage method, and the image is compressed through uni.compressImage. Compression quality can be set by specifying the quality attribute, which ranges from 0-100. After the compression is successful, the compressed image path can be obtained through the success callback function, and the image can be processed in the callback function.

Through the above code examples, we can implement the image cropping and compression functions in uniapp. According to specific needs, corresponding attributes and parameters can be configured to achieve different processing effects. The image processing function has a wide range of application scenarios in actual development. I hope this article will be helpful to you.

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