CILinearGradient not linear?

FROM : George Orthwein
DATE : Mon May 29 20:13:15 2006

Ok, hopefully this is just me and I'm overlooking some Core Image 
setting. :)

Create a linear gradient in Core Image Fun House:
/Developer/Examples/Quartz/Core Image/FunHouse

and compare it to CTGradient which uses Core Graphics (set the test 
app to the default style):
http://blog.oofn.net/projects/misc

Compare with a Photoshop gradient if you like.

The CTGradient looks almost identical to the Photoshop gradient but 
the Core Image gradient differs quite a bit... showing more lighter 
tones and then dropping to black very quickly at the end. The 
midpoint is 32% black instead of 50%.

Could this possibly be my machine/video card (ati 9600xt)? A monitor 
color profile affecting core image?

Actually, I just noticed the example pic in the Core Image 
documentation also exhibits the sharp drop to black:
http://developer.apple.com/documentation/GraphicsImaging/Conceptual/
CoreImaging/ci_filters/chapter_5_section_10.html

And, I created a CIContext that used the CPU rather than GPU and got 
identical results:
http://developer.apple.com/qa/qa2005/qa1416.html

Hmmmm.

George