触摸时的FabricJS画布坐标

const canvas = new fabric.Canvas('canvas');

// 监听 touchstart 事件
canvas.on('touchstart', (event) => {
  const touch = event.touches[0]; // 获取第一个触摸点
  const pointer = new fabric.Point(touch.clientX, touch.clientY);
  console.log('Touch start:', pointer);
});

// 监听 touchmove 事件
canvas.on('touchmove', (event) => {
  event.preventDefault(); // 阻止浏览器默认行为，如滚动
  const touch = event.touches[0]; // 获取第一个触摸点
  const pointer = new fabric.Point(touch.clientX, touch.clientY);
  console.log('Touch move:', pointer);
});

// 监听 touchend 事件
canvas.on('touchend', (event) => {
  const touch = event.changedTouches[0]; // 获取最后一个触摸点
  const pointer = new fabric.Point(touch.clientX, touch.clientY);
  console.log('Touch end:', pointer);
});

const pointer = new fabric.Point(touch.clientX, touch.clientY);
const relativePointer = pointer.subtract(canvas.getPointer().originX, canvas.getPointer().originY);
console.log('Relative touch point:', relativePointer);