Re: [ft-devel] regarding freetype 2 cubic curve flattening

[Vivek Rathod]

Alexei,

I did not mean to talk about the tolerance on deviation.

I misunderstood this comment.
"/* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */"
Here, I think, the max deviation is in Hain's r s coordinate system(
section 3) and s is the actual control point distance limit.

In that case s_limit - calculated as "s_limit = L * (TPos)( ONE_PIXEL
/ 6 );" - is correct for comparing with distance of the control
points.

Sorry for this confusion.
Thanks.


On Mon, Oct 31, 2011 at 5:57 PM, Alexei Podtelezhnikov
<address@hidden> wrote:
> Hi All,
>
> I finally understand where Vivek is coming from. There is a temptation
> to tolerate deviations larger than ONE_PIXEL on long arches that may appear
> with larger font sizes (say, 24 pixels or more). Sure, they'll look
> smooth (not angular).
> We are not about smoothness though. We need correct pixel-by-pixel shape.
> Therefore, we *always* tolerate a constant fraction of ONE_PIXEL no matter
> how long the arch is.
>
> Alexei
>
>
>
>
>
> On Mon, Oct 31, 2011 at 7:51 AM, Alexei Podtelezhnikov
> <address@hidden> wrote:
>> On Mon, Oct 31, 2011 at 7:43 AM, Vivek Rathod <address@hidden> wrote:
>>> The formula for deviation ( from Hein's paper).
>>> d = dnorm * s ; here s is normalized ------------------- (1)
>>> so the formula when s is not normalized becomes d = dnorm * (s / L)  ;
>>> -----------------(2)
>>> and I think the L you are mentioning comes from this formula.
>>> therefore s = (dmax/dnorm) * L;
>>>
>>> Please correct me if I am wrong about this whole normalization assumption.
>>
>> Stop confusing yourself and everybody else!
>> Do you know what ONE_PIXEL is? Learn that and read the damn code!
>> ONE_PIXEL is an absolute value and does not need any damn normalization.
>>
>
>
>
> --
> Alexei A. Podtelezhnikov, PhD
>