Article View: comp.sys.next.programmer
Article #1466Re: PS Level 2 image interpolation
From: Jim DeLaHunt
Date: Wed, 14 Oct 1992 04:55
Date: Wed, 14 Oct 1992 04:55
23 lines
1725 bytes
1725 bytes
In article <1992Oct12.185740.28980@slate.mines.colorado.edu>
cartley@slate.mines.colorado.edu (Craig Artley) writes:
>I'm trying to enable Level 2 image interpolation by setting Interpolate
>to true in the image dictionary.... Unfortunately, when i run the code
>below I simply get the same checkerboard result as when interpolation
>is disabled.
Read p. 222 of the Red Book carefully. "[The image interpolation algorithm]
_attempts_ to make a smooth transition between adjacent sample values"
[emphasis mine]. In other words, there is no guarantee about what adjustment
the algorithm makes, or in what circumstances.
Your sample image is a) small and b) 8 bits-per-pixel. Either of these
can prevent interpolation from happening. Try it with a 10x10 1 bit-per-
sample image. You should see interpolation there.
> -craig
>--
>Craig Artley cartley@mines.colorado.edu (303) 273-3557
>Dept. of Geophysics, Colorado School of Mines, Golden, CO 80401
--Jim DeLaHunt, Developer Support, Adobe Systems Incorporated
delahunt@adobe.com ...!{apple,decwrl}!adobe!delahunt +1-415-962-3790
Technical Details
Message-ID:
<1992Oct14.045520.26791@adobe.com>Path:
arc1-ca.pugleaf.net!sparky!uunet!ukma!cs.widener.edu!iggy.GW.Vitalink.COM!lll-winken!decwrl!adobe!delahuntReferences:
<1992Oct12.185740.28980@slate.mines.colorado.edu>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!sparky!uunet!ukma!cs.widener.edu!iggy.GW.Vitalink.COM!lll-winken!decwrl!adobe!delahunt From: delahunt@adobe.com (Jim DeLaHunt) Newsgroups: comp.sys.next.programmer,comp.lang.postscript Subject: Re: PS Level 2 image interpolation Summary: Interpolation doesn't always happen; details implementation-dependent Keywords: Level 2 image interpolation Message-ID: <1992Oct14.045520.26791@adobe.com> Date: 14 Oct 92 04:55:20 GMT References: <1992Oct12.185740.28980@slate.mines.colorado.edu> Sender: usenet@adobe.com (USENET NEWS) Organization: Adobe Systems Incorporated Lines: 23