[OpenJDK 2D-Dev] ArcIterator#btan(double)

[Ralph Hummeling]

Nope, didn't check-out the code with any version system. Just looked at 
it in NetBeans IDE.

Kind regards,

Ralph Hummeling
+316 5758 1679
Hummeling Engineering BV
www.hummeling.com

On 14/08/18 16:33, Krishna Addepalli wrote:
> I guess you would already have the code checked out? It is just a matter of updating the comments explaining how sin(a/2) / (1 + cos(a/2)) is equal to tan(a/4), and then change it in the code.
> I think you would need a test along with it.
> 
> Thanks,
> Krishna
> 
> -----Original Message-----
> From: Ralph Hummeling <engineering at hummeling.com>
> Sent: Tuesday, August 14, 2018 7:59 PM
> To: Krishna Addepalli <krishna.addepalli at oracle.com>; 2d-dev at openjdk.java.net
> Cc: james.graham at oracle.com
> Subject: Re: [OpenJDK 2D-Dev] ArcIterator#btan(double)
> 
> Dear Krishna,
> 
> I'd love to. How do I best do that?
> 
> 
> Kind regards,
> 
> Ralph Hummeling
> +316 5758 1679
> Hummeling Engineering BV
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.hummeling.com&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=iFb2N0ZBD0EAiVLz7h0dhj41Ha2uquc9ZM_GpTwq_w8&s=ypabzzNLUNIyzlXJK9-g27W-gz6a1phXmPa771N3ZGU&e=
> 
> On 13/08/18 08:39, Krishna Addepalli wrote:
>> Dear Ralph,
>>
>> Thanks for pointing this out, could you also come up with a patch for the same?
>>
>> Thanks,
>> Krishna
>>
>> -----Original Message-----
>> From: Ralph Hummeling <engineering at hummeling.com>
>> Sent: Friday, July 20, 2018 8:25 PM
>> To: 2d-dev at openjdk.java.net
>> Cc: james.graham at oracle.com
>> Subject: [OpenJDK 2D-Dev] ArcIterator#btan(double)
>>
>> Dear Java 2D dev team,
>>
>> I came across your java.awt.geom.ArcIterator class in which an arc Bezier control point segment length is determined in method btan(double). You arrive at the following equation:
>> 4/3*(1 - cos(a/2))/(sin(a/2))
>>
>> It is mentioned that this can return NaN for small "a" and so it is written as:
>> 4/3*(sin(a/2))/(1 + cos(a/2))
>>
>> Please note that this relation can also be written as follows:
>> 4/3*tan(a/4)
>>
>> A performance increase and no NaN issues ;-)
>>
>>
>> Kind regards,
>>
>> Ralph Hummeling
>> +316 5758 1679
>> Hummeling Engineering BV
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.hummeling.com&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=iFb2N0ZBD0EAiVLz7h0dhj41Ha2uquc9ZM_GpTwq_w8&s=ypabzzNLUNIyzlXJK9-g27W-gz6a1phXmPa771N3ZGU&e=
>>