tinting an NSImage

FROM : Mark Lilback
DATE : Sat Oct 02 23:26:54 2004

I'm working on a project that needs to take a bitmap image provided
by the user and transform it so that it will print on a printing
press with a single color specified by the user (basically grayscale
with an arbitrary color instead of black).

The Monochrome Image sample code shows how to get a grayscale image,
but I'd need to switch from NSCalibratedWhiteColorSpace to a color
space I create.

I can't find much documentation on NSNamedColorSpace and
NSCustomColorSpace, except the docs for NSDrawBitmap() says that
NSCustomColorSpace says to use the current colorspace of the graphics
context. So I set the colorspace using CGContextSetStrokeColorSpace
and CGContextSetFillColorSpace but then [NSBitmapImageRep
initWithBitmapDataPlanes:...] reports "Bad colorspace name
NSCustomColorSpace".

I've also tried creating a CSImageRef from the monochrome bitmap but
substituting a colorspace create with
CGColorSpaceCreateCalibratedGray using the desired color as the black
point. That doesn't work either.

Does anyone know how to use NSCustomColorSpace and/or
NSNamedColorSpace? Or better yet, does anyone have a better idea on
how to switch a grayscale image to use another color as the black
point?

TIA

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