How to implement image processing and filter effects in uniapp

How to achieve image processing and filter effects in uniapp

In the popular background of modern social media, people have more and more demands for the beauty and personalization of photos. high. In order to meet this demand, we usually use various image processing and filter effects to make the photos more colorful and vivid. Using the uniapp framework, we can easily implement image processing and filter effects. This article will introduce how to implement image processing and filter effects in uniapp, and provide specific code examples.

1. Image processing

1. Image size adjustment

In uniapp, you can easily adjust the image size with the help of the "canvas" component. The following is a sample code to adjust the image size to 150px * 150px:

<template>
  <view>
    <canvas id="canvas" :style="{width: '150rpx', height: '150rpx'}"></canvas>
  </view>
</template>

<script>
  export default {
    onReady() {
      const ctx = uni.createCanvasContext('canvas')
      uni.getImageInfo({
        src: '/static/path/to/image.jpg',
        success(res) {
          ctx.drawImage(res.path, 0, 0, 150, 150)
          ctx.draw()
        }
      })
    }
  }
</script>

2. Image cropping

With the cropping function of the "canvas" component, we can realize the image cropping Partial cropping. The following is a sample code to crop the picture into a circle:

<template>
  <view>
    <canvas id="canvas" :style="{width: '150rpx', height: '150rpx'}"></canvas>
  </view>
</template>

<script>
  export default {
    onReady() {
      const ctx = uni.createCanvasContext('canvas')
      const radius = 75 // 圆形直径的一半
      uni.getImageInfo({
        src: '/static/path/to/image.jpg',
        success(res) {
          ctx.save()
          ctx.beginPath()
          ctx.arc(radius, radius, radius, 0, 2 * Math.PI)
          ctx.clip()
          ctx.drawImage(res.path, 0, 0, radius * 2, radius * 2)
          ctx.draw()
        }
      })
    }
  }
</script>

2. Filter effect

To achieve the filter effect in uniapp, we can set each through the "filter" style attribute filter effect. The following is a sample code that applies a black and white filter effect to a picture:

<template>
  <view>
    <image src="/static/path/to/image.jpg" :style="{filter: 'grayscale(100%)'}"></image>
  </view>
</template>

3. Summary

Through the uniapp framework, we can easily achieve image processing and filter effects. This article introduces how to implement image resizing, image cropping, and filter effects, and provides specific code examples. With these techniques, we can add more personalization and beauty to our applications. I hope this article can be helpful to everyone.

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