Re: [ft-devel] cubic clean up

[Алексей Подтележников]

I think I can get though to this guy...

2010/11/12 David Bevan <address@hidden>:

> I've just had a brief chance to look at your proposal, and I now understand 
> why it makes no difference to the output. The chances of your relaxed 
> condition causing a split when the current (theoretically correct) condition 
> doesn't is very small: a control point would have to be in the small white 
> areas in the bottom corners of the rectangle in your diagram. Note that this 
> check is only made after subdivisions for the distance from the chord. Since 
> this is the most expensive test, it is done last, and normally only once.

Think about it a little more. Imagine a long chord of a dozen pixels.
Those white areas are vanishing.
Now think about a short chord of a pixel and a half.
Those areas are large. However, do you really want to flatten a
curve which pitches orthogonally? Think about it.

> Since there is no performance improvement, I don't believe that your proposal 
> should be included in the code. It would make the code more opaque: It is 
> obvious why the current code [if P1 or P2 is outside P0-P3, split the curve] 
> does what it does (especially if reference is made to Hain's paper); it would 
> not be at all clear why your condition for splitting [if P1 or P2 is far from 
> the center of P0-P3, split the curve] was there.

Let's face it. It's only you and me who understand these conditions.
You were able to understand my code. Let's drop the "opaque" argument.
I changed the comment for a reason. We can improve it more.