[IPP] (PWG) Raster Question on what is required

[IPP] (PWG) Raster Question on what is required

[IPP] (PWG) Raster Question on what is required

Petrie, Glen glen.petrie at eitc.epson.com
Thu Apr 28 20:22:46 UTC 2011



Question on your definition of bytes-per-line (BPL): You have it ending
at an octet (8-bit) but I have seen cases where the boundary is at the
word or 32-bit level.   In fact, I have seen were people clip a line by
changing the number of pixel per line but not the bytes-per-line.   What
has been your experience?   Suggestion: Leave the equation out of
specification and it is understood or is stated that new raster lines
begin at multiples of bpl.






From: Michael Sweet [mailto:msweet at apple.com] 
Sent: Thursday, April 28, 2011 10:27 AM
To: Petrie, Glen
Cc: ipp at pwg.org
Subject: Re: [IPP] (PWG) Raster Question on what is required


On Apr 28, 2011, at 10:21 AM, Petrie, Glen wrote:




	libtiff (the most widely-used TIFF library) supports 16-bits per


	I must be looking at the wrong version because TIFF 6.0 shows
only <8,8,8> http://www.libtiff.org/support.html


Hmm, they must have removed 16-bit support at one point - back when I
was doing print software for SGI workstations the "Sam Leffler" version
of libtiff supported it...


I think for interoperability we want a minimum set for interoperability
(and to address the use cases/design requirements). But most values of
color space and bit depth should be optional.


Ok, then from your color-spaces, the required bits-per-color would 1 and
8.  Also, the required bits-per-pixel would be 1, 8, 24





	One more time.  Does conformance to pwg-raster-back-side mean
"the printer will perform the indicated transforms" or this is an
identifier stating what the "state" of the back-side image is?


Conformance for a printer means that it will advertise what it needs.
For a client it means the client will transform the back side images as
indicated by the printer.


Michael Sweet, Senior Printing System Engineer, PWG Chair


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