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Auteur: salsaman
Datum:  
Aan: Minimalistic plugin API for video effects
Onderwerp: Re: [Frei0r] How should double be interpreted as screen positions?
Still not quite right....actually I think you need two translations and a
rotation:

1) translate offset centre to rotation center
2) perform the rotation about the rotation center
3) perform the reverse of 1, rotating the translation vector about the
rotation centre

Would that work ? It's nice because it keeps everything symmetric. You just
need to set the ro defaults to 0.0.

Salsaman.



http://lives.sourceforge.net
https://www.ohloh.net/accounts/salsaman



On Tue, Nov 27, 2012 at 10:00 AM, salsaman <salsaman@???> wrote:

> In addition, I should have added, rotation offset adds 2*ro translation to
> the frame in the opposite direction.
>
> so: ro = 0.0, 0.0
> x = 1.0, y=1.0
>
> does exactly what you wanted.
>
>
> Salsaman.
>
>
> http://lives.sourceforge.net
> https://www.ohloh.net/accounts/salsaman
>
>
>
>
> On Tue, Nov 27, 2012 at 9:57 AM, salsaman <salsaman@???> wrote:
>
>> That doesn't seem right...surely it should be symmetrical. Can you not
>> add a rotation offset, so:
>>
>> rot_offset = 0.5 = rotate about center, rot offset 0. = rotate about
>> top/left, 1.0 = rotate about bottom/right ?
>>
>> Salsaman.
>>
>>
>>
>> http://lives.sourceforge.net
>> https://www.ohloh.net/accounts/salsaman
>>
>>
>>
>>
>> On Tue, Nov 27, 2012 at 7:34 AM, Janne Liljeblad <
>> janne.liljeblad@???> wrote:
>>
>>> Update for ranges.
>>>
>>> I actually really need to have 2 frame widths on right/down direction
>>> too to allow for rotation before animating in, so the range
>>> interpretation will be:
>>>
>>> 0 = top/left 2 frame widths left/up
>>> 0.2 = top/left 1 frame width left/up
>>> 0.4 = top/left aligned with dest image
>>> 0.6 = top/left just out of dest image bottom/right corner
>>> 0.8 = top/left 1 frame width down/right
>>> 1.0 = top/left 2 frame widths down/right
>>>
>>>
>>> Janne
>>> _______________________________________________
>>> Frei0r mailing list - http://frei0r.dyne.org
>>> Free video plugins, minimal and cross-platform.
>>> http://mailinglists.dyne.org/cgi-bin/mailman/listinfo/frei0r
>>>
>>
>>
>