Re: Final round with NSTIFFCompressionCCITTFAX3
Re: Final round with NSTIFFCompressionCCITTFAX3
- Subject: Re: Final round with NSTIFFCompressionCCITTFAX3
- From: Ben Mackin <email@hidden>
- Date: Wed, 11 Sep 2002 19:32:20 -0700
On 9/11/02 7:23 PM, "Cameron Hayne" <email@hidden> wrote:
>
Shouldn't the first line be:
>
myDict = [NSDictionary dictionaryWithObjectsAndKeys:
>
[NSNumber numberWithInt:NSTIFFCompressionCCITTFAX3],
>
NSImageCompressionMethod, nil]; ?
Doesn't matter, I end up with the same thing.
I should be getting a 1-bit black and white image. The tiff you get is the
same as if you ran it with NSTIFFCompressionNone instead of
NSTIFFCompressionCCITTFAX3. So the tiff you get is just a normal tiff file.
I just found an old email, which advised me to look into the appkit
documentation (I thought I did, but must have missed something).
>
> If compression is NSTIFFCompressionCCITTFAX3, then the data must be one
>
> bit-per-sample and one sample-per-pixel
So it turns out I need to pass in a one bit-per-sample and one
sample-per-pixel (ie black and white) to get the file I want. So my issue
now is that I need a routine to convert to black and white, instead of
greyscale.
I am not sure on the algorithm to convert to black and white, but I heard it
is pretty difficult. I am surprised that no such routine exists to convert
to black and white (or does one, and I have overlooked it).
Thanks,
Ben
http://www.shayufilms.com
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