How to use Vue to implement image mosaic and graffiti functions?

How to use Vue to realize the mosaic and graffiti functions of pictures?

With the rapid development of mobile Internet, people's demand for photo processing is also getting higher and higher. Nowadays, on the mobile and web sides, it is no longer a problem to use the Vue framework to realize the mosaic and graffiti functions of images. The Vue framework provides powerful data-driven and component-based development capabilities, making it possible to implement these functions.

This article will introduce how to use Vue to realize the mosaic and graffiti functions of images, and give corresponding code examples.

First, we need to introduce relevant components and libraries into the Vue project. In this article, we will use the vue-konva library to implement the graffiti function, and the canvas element to implement the mosaic function. You can install these libraries through npm:

npm install vue-konva

Next, we will create a Vue component to display pictures and implement mosaic and graffiti functions. Here is a simple sample code:

<template>
  <div>
    <img  src="/static/imghwm/default1.png"  data-src="imageUrl"  class="lazy"  : @load="handleImageLoad" / alt="How to use Vue to implement image mosaic and graffiti functions?" >
    <canvas ref="canvas" @mousedown="handleMouseDown" @mousemove="handleMouseMove" @mouseup="handleMouseUp"></canvas>
    <v-stage ref="stage">
      <v-layer>
        <v-image ref="image" :image="loadedImage" />
        <v-line ref="line" />
      </v-layer>
    </v-stage>
  </div>
</template>

<script>
import Vue from 'vue'
import VueKonva from 'vue-konva'

Vue.use(VueKonva)

export default {
  data() {
    return {
      imageUrl: '',       // 图片地址
      loadedImage: null,  // 加载后的图片对象
      isDrawing: false,   // 是否在涂鸦中
      lastPointerPosition: { x: 0, y: 0 }  // 上一个鼠标指针的位置
    }
  },
  methods: {
    handleImageLoad() {
      const image = new Image()
      image.src = this.imageUrl

      image.onload = () => {
        this.loadedImage = image
        this.$refs.stage.getStage().batchDraw()
      }
    },
    handleMouseDown(e) {
      this.isDrawing = true
      this.lastPointerPosition = this.getRelativePosition(e)
      this.$refs.line.points([this.lastPointerPosition.x, this.lastPointerPosition.y])
      this.$refs.stage.getStage().batchDraw()
    },
    handleMouseMove(e) {
      if (!this.isDrawing) {
        return
      }
      const newPointerPosition = this.getRelativePosition(e)
      const points = this.$refs.line.points()
      const newPoints = points.concat([newPointerPosition.x, newPointerPosition.y])

      this.$refs.line.points(newPoints)
      this.$refs.stage.getStage().batchDraw()

      this.lastPointerPosition = newPointerPosition
    },
    handleMouseUp() {
      this.isDrawing = false
    },
    getRelativePosition(e) {
      const stage = this.$refs.stage.getStage().container()
      const pos = stage.getBoundingClientRect()

      return {
        x: e.clientX - pos.left,
        y: e.clientY - pos.top
      }
    }
  },
  mounted() {
    const canvas = this.$refs.canvas
    const context = canvas.getContext('2d')

    const image = new Image()
    image.src = this.imageUrl

    image.onload = () => {
      canvas.width = image.width
      canvas.height = image.height

      context.drawImage(image, 0, 0, image.width, image.height)
    }
  }
}
</script>

In the above code, we first introduce the required libraries and define an img## in the template tag The # element is used to display images. Next, we created a canvas element and a v-stage component to implement the mosaic and graffiti functions respectively. In the mounted hook function, we use the getContext method of canvas to obtain the context of the canvas, and draw it to the canvas after the image is loaded.

Next, we define some event handling functions. The

handleImageLoad function draws the image into the v-stage component after it is loaded. handleMouseDownThe function starts graffiti when the mouse is pressed, and updates the graffiti path when the mouse is moved and released. The handleMouseMove function uses the v-line component in the vue-konva library to draw the path. handleMouseUpThe function ends graffiti when the mouse is released. getRelativePositionThe function is used to get the position of the mouse relative to the canvas.

Finally, we use the

$refs attribute in the mounted hook function to obtain the relevant DOM element and bind the event to it.

In the implementation of Vue, we can put the above code in a Vue component and reference the component in other components to realize the mosaic and graffiti functions of pictures.

Based on the Vue framework and related libraries, we can easily implement the mosaic and graffiti functions of images. This example is just one of the implementation methods, and you can make corresponding adjustments and improvements according to actual needs. I hope this article will help you understand and master the implementation of mosaic and graffiti functions in Vue.

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