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

[Petrie, Glen]

Mike,

 

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.

 

Glen

 

 

________________________________

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
color.

	 

	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

 

Right.

 

	

	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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