How to get the Active Selection objects position relative to canvas

[sohailahmad07]

Hi when i select multiple objects the position becomes relative to object but i want to get the object's position relative to the canvas

**what i am trying to achieve **

i have a canvas and all of the canvas data is store on the backend in a database i save the json of every object as a separate item assign to a user

Elemenets -> table_name
id
ele_json
user_id
board_id

Problem

the problem is when the user selects multiple objects and moves i send an Axios request to my backend to update object JSON in the database and when i refresh (to simulate the user coming back to the board on a later time) the object are no longer there because when i send the data all of the object position were according to the active selection and not canvas

[asturur]

The export of an active selection today is backed in the canvas export and is not great.
The canvas does this:

  /**
   * Realizes an object's group transformation on it
   * @private
   * @param {FabricObject} [instance] the object to transform (gets mutated)
   * @returns the original values of instance which were changed
   */
  private _realizeGroupTransformOnObject(
    instance: FabricObject
  ): Partial<typeof instance> {
    const { group } = instance;
    if (group && isActiveSelection(group) && this._activeObject === group) {
      const layoutProps = [
        'angle',
        'flipX',
        'flipY',
        LEFT,
        'scaleX',
        'scaleY',
        'skewX',
        'skewY',
        TOP,
      ] as (keyof typeof instance)[];
      const originalValues = pick<typeof instance>(instance, layoutProps);
      addTransformToObject(instance, group.calcOwnMatrix());
      return originalValues;
    } else {
      return {};
    }
  }

It saves the current object transform state,
it apply back the group transform
it exports
and it puts back the original values

It is not a good flow and prone to errors, but as of now it is how is done

[asturur]

those methods are fabric exports.
On what fabric version are you?

[sohailahmad07]

HI Sir

"fabric": "^5.3.0",

i would appreciate if you can the code in a bit detail right now the above code i give will create trigger when object:modified EVENT is trigger

Thanks in advance

[asturur]

Sorry i can't write out all the solution for fabric 5.3, you could have mentioned it when you opened the post, at least i would have used my time in that way.
But if you look at the canvas function toObject and how it handle the active selection, you can just copy the code from there.

[sohailahmad07]

ok i can upgrade the fabric to next stable version if the solution is easy there

Should i upgrade to 6x

[asturur]

But if you open fabric 5.3 Canvas toObject method the solution is there by reading the code, what is wrong about that?