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vue 实现图片截取

2026-01-18 16:32:16VUE

使用 Vue 实现图片截取

在 Vue 中实现图片截取功能通常需要借助第三方库或原生 Canvas API。以下是两种常见的方法：

使用 cropperjs 库

安装 cropperjs 库：

npm install cropperjs

在 Vue 组件中使用：

vue 实现图片截取

<template>
  <div>
    <img ref="image" src="your-image-source.jpg" alt="Image to crop">
    <button @click="cropImage">Crop</button>
  </div>
</template>

<script>
import Cropper from 'cropperjs';
import 'cropperjs/dist/cropper.css';

export default {
  mounted() {
    this.cropper = new Cropper(this.$refs.image, {
      aspectRatio: 16 / 9,
      viewMode: 1,
    });
  },
  methods: {
    cropImage() {
      const canvas = this.cropper.getCroppedCanvas();
      const croppedImage = canvas.toDataURL('image/jpeg');
      // 使用 croppedImage，可以显示或上传
    }
  },
  beforeDestroy() {
    this.cropper.destroy();
  }
};
</script>

使用原生 Canvas API

<template>
  <div>
    <input type="file" @change="loadImage" accept="image/*">
    <canvas ref="canvas"></canvas>
    <button @click="crop">Crop</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      image: null,
      ctx: null,
      startX: 0,
      startY: 0,
      endX: 0,
      endY: 0,
      isDragging: false
    };
  },
  mounted() {
    this.ctx = this.$refs.canvas.getContext('2d');
  },
  methods: {
    loadImage(e) {
      const file = e.target.files[0];
      const reader = new FileReader();

      reader.onload = (event) => {
        this.image = new Image();
        this.image.onload = () => {
          this.$refs.canvas.width = this.image.width;
          this.$refs.canvas.height = this.image.height;
          this.ctx.drawImage(this.image, 0, 0);
        };
        this.image.src = event.target.result;
      };
      reader.readAsDataURL(file);
    },
    crop() {
      const width = this.endX - this.startX;
      const height = this.endY - this.startY;
      const data = this.ctx.getImageData(this.startX, this.startY, width, height);

      this.$refs.canvas.width = width;
      this.$refs.canvas.height = height;
      this.ctx.putImageData(data, 0, 0);
    }
  }
};
</script>

实现拖拽选择区域功能

为上述 Canvas 方案添加鼠标事件处理：

// 在 mounted 中添加事件监听
this.$refs.canvas.addEventListener('mousedown', this.startSelection);
this.$refs.canvas.addEventListener('mousemove', this.drawSelection);
this.$refs.canvas.addEventListener('mouseup', this.endSelection);

// 添加方法
methods: {
  startSelection(e) {
    this.isDragging = true;
    this.startX = e.offsetX;
    this.startY = e.offsetY;
    this.endX = e.offsetX;
    this.endY = e.offsetY;
  },
  drawSelection(e) {
    if (!this.isDragging) return;
    this.endX = e.offsetX;
    this.endY = e.offsetY;

    // 清除并重绘
    this.ctx.clearRect(0, 0, this.$refs.canvas.width, this.$refs.canvas.height);
    this.ctx.drawImage(this.image, 0, 0);

    // 绘制选择框
    this.ctx.strokeStyle = 'red';
    this.ctx.lineWidth = 2;
    this.ctx.strokeRect(
      this.startX,
      this.startY,
      this.endX - this.startX,
      this.endY - this.startY
    );
  },
  endSelection() {
    this.isDragging = false;
  }
}