jQuery animate passes fixed firstNum, diff to easing function

[tomalec]

jQuery.animete uses easing function with firstNum, diff always set to 0,1:

this.pos = jQuery.easing[specialEasing || defaultEasing](this.state, n, 0, 1, this.options.duration);
this.now = this.start + ((this.end - this.start) * this.pos);

So these parameters are completely useless for easing functions; for example:

swing: function( p, n, firstNum, diff ) {
			return ((-Math.cos(p*Math.PI)/2) + 0.5) * diff + firstNum;
		}
}}

Could be changed to:

swing: function( p, n ) {
			return ((-Math.cos(p*Math.PI)/2) + 0.5);
		}
}}

I suggest changing it to:

this.pos = jQuery.easing[specialEasing || defaultEasing](this.state, n, this.start, this.end - this.start , this.options.duration);
this.now = this.pos;

[john]

Let's look at this for 1.7.

[john]

Nominating ticket for 1.7 discussion.

[Rick Waldron]

+0,

[jaubourg]

-1, This will break plugins defining their own easing methods since it changes the scale of the arguments if I understand correctly

[timmywil]

-1, customizing swing is valid

[john]

+0, So yeah, it's not terribly useful in its current state - but making this change will break API, which is... quite bad.

[scottgonzalez]

-1, this is like fixing .each(), it'd be a better API, but break all existing code

[addyosmani]

-1

[ajpiano]

-1, Seems like an unwise thing to break

[tomalec]

Replying to john: Break API? In my opinion it will fix the API, since real first number and difference can be different that 0 and 1. But for sure it can break things that uses this variables and assumes that they are static 0, 1 (which is also quite bad)

Replying to ajpiano: So maybe make firstNum and diff represent first number and difference, not the 0, and 1?

[jzaefferer]

-1

[Rick Waldron]

Closing per 1.7 roadmap meeting resolution