vue进行图片标注，放大，缩小并存储标注数据

要实现图片标注、放大、缩小并存储标注数据，可以使用以下步骤：

1. 加载图片：使用Vue的`<img>`标签加载图片。
2. 标注图片：使用Vue的`<canvas>`标签绘制图片，通过鼠标事件监听用户的标注操作，将标注数据存储在Vue的数据中。
3. 放大、缩小：通过CSS的`transform`属性实现图片的放大、缩小效果，同时也需要更新绘制标注的画布大小和坐标。
4. 存储标注数据：将标注数据存储在本地存储或后端数据库中，可以使用Vue的`localStorage`或`axios`库实现。

下面是一个简单的示例代码：

<template>
  <div>
    <img ref="image" :src="imageUrl" @load="onImageLoad">
    <div ref="canvasWrapper" class="canvas-wrapper">
      <canvas ref="canvas" @mousedown="onMouseDown" @mousemove="onMouseMove" @mouseup="onMouseUp"></canvas>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      imageUrl: 'https://image.url',
      imageWidth: 0,
      imageHeight: 0,
      canvasWidth: 0,
      canvasHeight: 0,
      canvasLeft: 0,
      canvasTop: 0,
      isMouseDown: false,
      startX: 0,
      startY: 0,
      annotations: []
    }
  },
  methods: {
    onImageLoad() {
      this.imageWidth = this.$refs.image.width
      this.imageHeight = this.$refs.image.height
      this.canvasWidth = this.imageWidth
      this.canvasHeight = this.imageHeight
      this.$refs.canvas.width = this.canvasWidth
      this.$refs.canvas.height = this.canvasHeight
      this.canvasLeft = this.$refs.canvasWrapper.offsetLeft
      this.canvasTop = this.$refs.canvasWrapper.offsetTop
      this.drawAnnotations()
    },
    onMouseDown(event) {
      this.isMouseDown = true
      this.startX = event.pageX - this.canvasLeft
      this.startY = event.pageY - this.canvasTop
    },
    onMouseMove(event) {
      if (this.isMouseDown) {
        const x = event.pageX - this.canvasLeft
        const y = event.pageY - this.canvasTop
        const width = x - this.startX
        const height = y - this.startY
        const annotation = { x: this.startX, y: this.startY, width, height }
        this.annotations.push(annotation)
        this.drawAnnotations()
      }
    },
    onMouseUp() {
      this.isMouseDown = false
    },
    drawAnnotations() {
      const ctx = this.$refs.canvas.getContext('2d')
      ctx.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
      ctx.drawImage(this.$refs.image, 0, 0, this.imageWidth, this.imageHeight)
      for (const annotation of this.annotations) {
        ctx.strokeRect(annotation.x, annotation.y, annotation.width, annotation.height)
      }
    },
    zoomIn() {
      this.canvasWidth *= 1.2
      this.canvasHeight *= 1.2
      this.$refs.canvas.width = this.canvasWidth
      this.$refs.canvas.height = this.canvasHeight
      this.drawAnnotations()
    },
    zoomOut() {
      this.canvasWidth /= 1.2
      this.canvasHeight /= 1.2
      this.$refs.canvas.width = this.canvasWidth
      this.$refs.canvas.height = this.canvasHeight
      this.drawAnnotations()
    },
    saveAnnotations() {
      localStorage.setItem('annotations', JSON.stringify(this.annotations))
    },
    loadAnnotations() {
      const annotations = JSON.parse(localStorage.getItem('annotations'))
      if (annotations) {
        this.annotations = annotations
        this.drawAnnotations()
      }
    }
  }
}
</script>

<style scoped>
.canvas-wrapper {
  position: relative;
  overflow: hidden;
}
canvas {
  position: absolute;
  top: 0;
  left: 0;
}
</style>