lockRotation and object:modified event

[lukejagodzinski]

Hi, I've noticed strange behavior when trying to rotate object that has lockRotation set to true. At first it performs object:rotating event on object even that it's not rotating. And what is even more unwanted when rotation is finished it fires object:modified but nothing has changed. When I investigated what properties has changed using this code:

fabric.Object.prototype.hasStateChanged = function() {
  this.stateProperties.forEach(function(prop) {
    if (this.get(prop) !== this.originalState[prop]) {
      console.log('hasStateChanged(' + prop + ')')
      console.log('    current:  ' + this.get(prop));
      console.log('    original: ' + this.originalState[prop]);
    }
  }.bind(this));

  return this.stateProperties.some(function(prop) {
    return this.get(prop) !== this.originalState[prop];
  }, this);
};

it appeared to be left, top, originX, originY properties. I understand that it's because of changing origin point to center, center while rotating. But origin change shouldn't happen at all because rotation had been locked. When I set lockRotation to false it's detecting change of angle property and those four previously mentioned. But it should only show angle. My conclusion is that it shouldn't detect properties change if those properties were modified only as a side effect of transformation. Probably the same situation has place if it goes about scaling.

// From console
hasStateChanged(top) fabric.js:12846
    current:  196.06459398155516 fabric.js:12847
    original: 71.06459398155516 fabric.js:12848
hasStateChanged(left) fabric.js:12846
    current:  627.9755859375 fabric.js:12847
    original: 559.55517578125 fabric.js:12848
hasStateChanged(originX) fabric.js:12846
    current:  center fabric.js:12847
    original: left fabric.js:12848
hasStateChanged(originY) fabric.js:12846
    current:  center fabric.js:12847
    original: top 

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[lukejagodzinski]

Problem can be solved by moving the line this._restoreOriginXY(target); before the target.hasStateChanged() function. But this change will probably cause another error - lack of change detection of originX and originY. But is it a problem?

Actually fabric.Canvas.prototype._finalizeCurrentTransform function is only executed on mouseup event. Is there any chance that origin will change permanently (without going to previous state) during object transformation?

fabric.Canvas.prototype._finalizeCurrentTransform: function() {

  var transform = this._currentTransform,
      target = transform.target;

  if (target._scaling) {
    target._scaling = false;
  }

  target.setCoords();

  this._restoreOriginXY(target); // THIS LINE WAS MOVED HERE FROM... ~~~~~~~~

  // only fire :modified event if target coordinates were changed during mousedown-mouseup
  if (this.stateful && target.hasStateChanged()) {
    this.fire('object:modified', {
      target: target
    });
    target.fire('modified');
  }

  // ... THIS POSITION ~~~~~~~~
};

[asturur]

Hi @jagi, sorry for not seeing this, but you were right about the position of restoreOriginXY.