Re: Image Processing using Cocoa: newbee question
Re: Image Processing using Cocoa: newbee question
- Subject: Re: Image Processing using Cocoa: newbee question
- From: Jeffrey Robert Kelley <email@hidden>
- Date: Thu, 14 Mar 2013 23:13:22 -0400
Lars,
It’s not as high-level as Core Image, but here’s a good primer on obtaining raw pixel data:
http://mikeash.com/pyblog/friday-qa-2012-08-31-obtaining-and-interpreting-image-data.html
- Jeff Kelley
On Mar 14, 2013, at 8:01 PM, Lars Sonchocky-Helldorf <email@hidden> wrote:
> Hi,
>
> I've never before done image (pixel) data processing in Cocoa before. Now I've heard of QuartzComposer and Core Image Units as the way to go nowadays. But, a big but comes here: When I process the image I need to have random access to all pixels because I want to do some floyd steinberg like dithering. Now:
>
> http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Conceptual/CoreImaging/ci_custom_filters/ci_custom_filters.html#//apple_ref/doc/uid/TP30001185-CH207-TPXREF101
>
> states: "A kernel routine signature must return a vector (vec4) that contains the result of mapping the source pixel to a destination pixel. Core Image invokes a kernel routine once for each pixel. Keep in mind that your code can’t accumulate knowledge from pixel to pixel."
>
> so I guess using Core Image to write a Custom Filter is beyond the means here.
>
> So what would be the appropriate stuff to look for when planing to do some image data processing using Cocoa assuming that I need random access at all the data (mainly to diffuse some quantization error to nearby pixels)?
>
>
> thanks,
>
> Lars
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