[gs-bugs] [Bug 689777] Smooth shades show 64 steps in psdcmyk output

bugs.ghostscript.com-bugzilla-daemon at ghostscript.com bugs.ghostscript.com-bugzilla-daemon at ghostscript.com
Wed Jul 16 15:08:38 PDT 2008


http://bugs.ghostscript.com/show_bug.cgi?id=689777

leonardo at artifex.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID



------- Additional Comments From leonardo at artifex.com  2008-07-16 15:08 -------
Analyzing with current HEAD :

The psdrgb device specifies GX_CINFO_SEP_LIN and zeros in 
color_info.comp_bits. These data are inconsistent and to be addressed to the 
device owner. When I set GX_CINFO_SEP_LIN_NONE, got same result as with 
psdcmyk.

With non-(separable and linear) devices, such as psdcmyk, the shading code 
cannot apply device linear color functions, and performs a decomposition into 
constant color rectangles until the color precision reaches 
the 'setsmoothness' value. Since the tests do not specify one, the default 
value 0.02 is used. It gives the 64 grades of the color. When I insert "1 256 
div setsmoothness", the result looks smoother (well here we reach another 
limitation - 8bpc (which I believe is used in psdcmyk) limits us with 256 
grades. 

So IMO what the customer observes is a correct behavior, so I'll close it as 
invalid. Support should move the psdrgb problem to a separate bug with a 
proper assignment.



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