Re: changing brightness and contrast in an nsimage
Re: changing brightness and contrast in an nsimage
- Subject: Re: changing brightness and contrast in an nsimage
- From: Eric Smith <email@hidden>
- Date: Sat, 3 Dec 2005 21:39:02 -0800
OK... I've gone to the CIImage.
Next question: I can create a CIImage from NSBitmapImagRep, but all
I can get from the CIImage is an NSImageRep... this has no method for
getting at the bitmap data. Once I'm using a CIImage, how do I get
the bitmap data?
Thanks again,
Eric
On Dec 3, 2005, at 7:30 PM, Dave Camp wrote:
I think the problem is it isn't clear what you are asking for...
Are you asking for pointers to general brightness and contrast
algorithms?
Are you asking how to get at the NSImage bitmap data to manipulate
it yourself?
Or are you asking if there are other Apple supplied frameworks that
will perform brightness and contrast adjustments for you?
Dave
On Dec 3, 2005, at 8:04 PM, Eric Smith wrote:
CIImage wasn't even around until 10.4... there must be a way to
handle this from an NSImage. Anyone out there use brightness and
contrast controls on an NSImage, or the bitmap data associated
with the NSImage?
Thanks,
Eric
On Dec 2, 2005, at 9:34 PM, John C. Randolph wrote:
On Dec 2, 2005, at 9:29 PM, Eric Smith wrote:
I've been going around in circles with this one...
What is a good way to change the brightness and contrast in an
NSImage?
I've been playing with the vImage library for changing contrast,
using the vImageEndsInContrastStretch. This works, but how does
one return the contrast to it's original value? Once you
specify that > 0% of the pixels lie at the histogram extreme,
you can't get the original values back. I know of the ImagApp
example showing how to use CIImage, but using that would require
a re-write of quite a bit of code... I'd rather not go there.
Too bad, because that's how to do it.
-jcr
John C. Randolph <email@hidden> (408) 914-0013
Roaming Cocoa Engineer,
Available for your projects at great Expense and Inconvenience.
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