RE: [cgmo-webcgm] Question. "allowable" compression types

[Dieter Weidenbrück <dieter@itedo.com>]

Lofton,

see inline 

> -----Original Message-----
> From: Lofton Henderson [mailto:lofton@rockynet.com] 
> Sent: Monday, October 17, 2005 4:56 PM
> To: cgmo-webcgm@lists.oasis-open.org
> Subject: [cgmo-webcgm] Question. "allowable" compression types
> 
> Ref: 
> http://www.oasis-open.org/committees/download.php/14826/WebCGM
> 20-20051007.zip
> 
> Here is a loose end that has been kicking around for two years (since
> Houston) -- deprecated compression types in BITONAL TILE and 
> TILE.  If you look at the current editors draft, you'll see:
> 
> >T.19.28  BITONAL TILE
> >----------
> >List allowable compression types: 0, 1, 2, 5, or 6.
> >Requirements on row padding: None.
> >Other: The values 0, 1 are deprecated and may be removed 
> from a future 
> >version of WebCGM.
> 
> Green shading on 0, 1 in both places.  So apparently we 
> intend to deprecate those two, null background and null 
> foreground?  Deprecate means:  cannot appear in 2.0 content, 
> but viewers must be prepared to handle (in 1.0 content).
> 
> Agreed, is that what we finally resolved here?
As far as I can remember, yes.

> 
> >T.19.29  TILE
> >----------
> >List allowable compression types: 0, 1, 2, 5, 6, 7, or 9 
> Requirements 
> >on row padding: None.
> >Other: The value 9 is the ISO registered value for 
> compression method 0 
> >of PNG.
> >The values 0, 1, 2 are deprecated and...
> 
> 0,1 is green shaded in the first line, and 0,1,2 (2=Group3) 
> is green shaded in the last.
> 
> So what is it that we finally resolved for TILE?
deprecate 0,1,2

> 
> (Editorial comment -- IMO, these are all so trivial to 
> implement that I have trouble recalling why we decided to 
> deprecate in the first place.)
I think there is only one reason for this, to prevent users from
creating unreasonable CGM files with no compression or compression types
that are not efficient.

Dieter
> 
> -Lofton.
> 
> 
>