Bug 689668

Summary: Documentation on banding is unclear.
Product: Ghostscript Reporter: leonardo <leonardo>
Component: DocumentationAssignee: Ray Johnston <ray.johnston>
Status: NOTIFIED FIXED    
Severity: normal    
Priority: P2    
Version: master   
Hardware: PC   
OS: Windows XP   
Customer: Word Size: ---
Bug Depends on:    
Bug Blocks: 689534    

Description leonardo 2008-01-23 05:51:07 UTC 
End users want to know about Ghostscript banding methods from Use.htm . However 
this file contains only a misleading information about MaxBitmap. Some 
documentation onm banding parameters appears in Language.htm, but (1) end users 
can't understand this document because it is for Postscript programmers, (2) 
it's unclear how these parameters control the algorithm (3) from parameter 
names they look contradicting one another. For example, what happens if I set 
BandWidth=10, MaxBitmap=10000000 : will it cause vertical bands ???

Also need to explain that default settings are optimal for for 60 dpi A4, and 
they may be very inoptimal for bug pages such as bug 689155. Therefore big 
pages either need an improvement for the default setting code, or a manual 
adjustment for parameters.
Comment 1 leonardo 2008-04-27 23:30:14 UTC 
Repeating the bug description with fixed misprints :

End users want to know about Ghostscript banding methods from Use.htm . However 
this file contains only a misleading information about MaxBitmap. Some 
documentation on banding parameters appears in Language.htm, but (1) end users 
can't understand this document because it is for Postscript programmers, (2) 
it's unclear how these parameters control the algorithm (3) from parameter 
names they look contradicting one another. For example, what happens if I set 
BandWidth=10, MaxBitmap=10000000 : will it cause vertical bands ???

Also need to explain that default settings are optimal for for 600 dpi A4, and 
they may be very inoptimal for big pages such as bug 689155 or bBug 689534. 
Therefore big pages either need an improvement for the default setting code, or 
a manual adjustment for parameters.

Bumping the priority because mentioned customer bugs depend on it. Also I think 
Use.htm needs a new chapter "Parameters for rasterising big PDF pages".
Comment 2 Ray Johnston 2008-07-16 22:53:40 UTC 
Improvements committed in rev 8847. Obviously, anyone may have suggestions for
further improvements. Suggestions are welcome. and can be attached to this
bug (and the bug reopened), or a new bug opened, or simply email:
   gs-devel@ghostscript.com