Vue と Canvas: オンライン アバターのトリミングおよびサイズ変更ツールを実装する方法

<template>
  <div>
    <canvas ref="canvas" :width="canvasWidth" :height="canvasHeight"></canvas>
    <div>
      <button @click="rotateLeft">左旋转</button>
      <button @click="rotateRight">右旋转</button>
      <button @click="zoomIn">放大</button>
      <button @click="zoomOut">缩小</button>
      <button @click="crop">裁剪</button>
    </div>
  </div>
</template>

data() {
  return {
    canvasWidth: 600,  // canvas元素的宽度
    canvasHeight: 400, // canvas元素的高度
    image: null,      // 存储头像图片对象
    angle: 0,         // 头像的旋转角度
    scale: 1          // 头像的缩放比例
  };
}

created() {
  const img = new Image();
  img.src = 'path/to/your/image.jpg';  // 修改为你的头像图片路径
  img.onload = () => {
    this.image = img;
    this.draw();
  };
}

methods: {
  rotateLeft() {
    this.angle -= 90;
    this.draw();
  },
  rotateRight() {
    this.angle += 90;
    this.draw();
  },
  zoomIn() {
    this.scale *= 1.2;
    this.draw();
  },
  zoomOut() {
    this.scale /= 1.2;
    this.draw();
  },
  crop() {
    // 实现裁剪逻辑
  },
  draw() {
    const canvas = this.$refs.canvas;
    const ctx = canvas.getContext('2d');
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    ctx.save();
    ctx.translate(canvas.width / 2, canvas.height / 2);
    ctx.rotate((Math.PI / 180) * this.angle);
    ctx.scale(this.scale, this.scale);
    ctx.drawImage(
      this.image,
      -this.image.width / 2,
      -this.image.height / 2,
      this.image.width,
      this.image.height
    );
    ctx.restore();
  }
}

<template>
  <!-- ...省略其它部分... -->
    <div>
      <button @click="toggleCrop">裁剪模式</button>
      <button @click="clearCrop">清除裁剪</button>
    </div>
</template>

data() {
  return {
    // ...省略其它部分...
    cropMode: false,
    cropStartX: 0,
    cropStartY: 0,
    cropEndX: 0,
    cropEndY: 0
  };
},
methods: {
  // ...省略其它部分...
  toggleCrop() {
    this.cropMode = !this.cropMode;
    this.clearCrop();
  },
  clearCrop() {
    this.cropStartX = 0;
    this.cropStartY = 0;
    this.cropEndX = 0;
    this.cropEndY = 0;
    this.draw();
  }
}

draw() {
  // ...省略其它部分...
  if (this.cropMode) {
    ctx.lineWidth = 2;
    ctx.strokeStyle = 'red';
    ctx.strokeRect(this.cropStartX, this.cropStartY, this.cropEndX - this.cropStartX, this.cropEndY - this.cropStartY);
  }
}