FabricJs:从db重新加载canvas时，分组对象的部分被裁剪

// 获取之前保存的分组对象的位置和尺寸信息
var groupLeft = savedGroup.left;
var groupTop = savedGroup.top;
var groupWidth = savedGroup.width;
var groupHeight = savedGroup.height;

// 记录当前canvas的尺寸
var canvasWidth = canvas.getWidth();
var canvasHeight = canvas.getHeight();

// 重新加载canvas
// ...

// 将之前保存的分组对象的位置和尺寸信息应用到新的canvas上
var group = canvas.getActiveObject();
group.set({
  left: groupLeft,
  top: groupTop,
  width: groupWidth,
  height: groupHeight
});

// 如果新的canvas尺寸小于之前保存的尺寸，调整canvas尺寸
if (canvasWidth < groupWidth || canvasHeight < groupHeight) {
  canvas.setDimensions({
    width: Math.max(canvasWidth, groupWidth),
    height: Math.max(canvasHeight, groupHeight)
  });
}

// 渲染canvas
canvas.renderAll();