Re: NSImage > trapezium...

FROM : John Stiles
DATE : Mon Mar 24 03:39:27 2008

FWIW, if you find yourself needing to do much more in the way of
distorting images, I'd recommend looking into OpenGL directly.
It's extremely fast since it goes straight to the hardware, and doing
something like "map an image to a trapezoid" is /very/ few lines of
code. Much simpler than trying to do it yourself.


Cathy Shive wrote:
> Luca, I am sorry for being snippy.  I automatically assumed you were
> referring to an NSImage when all you said was image.  Many many
> apologies!!
>
> Glenn has you on the right track :)
>
> Again, good luck and sorry *blush*
> Cathy
>
>
> On Mar 23, 2008, at 3:10 PM, glenn andreas wrote:
>

>>
>> On Mar 23, 2008, at 8:54 AM, Cathy Shive wrote:

>>> On Mar 23, 2008, at 2:14 PM, Luca wrote:
>>>

>>>> Hello. Do you know how can I transform a rectangular image in a
>>>> trapezium?

>>>
>>> Seriously?
>>>
>>> You aren't going to be able to distort your bitmap like this with
>>> NSImage and there is no ready-made CIFilter to do this distortion
>>> that I'm aware of.  If I'm wrong about that, then that's the way to
>>> go.  But,  I think you've gotta do your own pixel pushing for this one.
>>>

>>
>> Actually, the CIPerspectiveTransform will do this perfectly (you even
>> just give it the resulting four corner points)
>>
>> You can't do that will an affine transform though (since perspective
>> is, by definition, non-affine), so you'll need to use CoreImage.
>>
>>
>> Glenn Andreas                      <email_removed>
>>  <http://www.gandreas.com/> wicked fun!
>> quadrium | flame : flame fractals & strange attractors : build,
>> mutate, evolve, animate
>>
>>
>>
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