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From: rslau@tarazed.usc.edu (Robert Lau)
Newsgroups: alt.graphics.pixutils,comp.graphics
Subject: Re: how to give pnmrotate a negative angle?
Message-ID: <RSLAU.91Feb6153854@tarazed.usc.edu>
Date: 6 Feb 91 23:38:54 GMT
References: <865@keele.keele.ac.uk>
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In-reply-to: cca13@seq1.keele.ac.uk's message of 6 Feb 91 14:21:20 GMT
Originator: rslau@tarazed.usc.edu

In article <865@keele.keele.ac.uk> cca13@seq1.keele.ac.uk (G.D. Pratt) writes:

   Can anyone tell me how to tell the pnmrotate command, in the new
   beta release of PBMPLUS, how to rotate the image by a negative angle
   since it appears to take the "-" as the flag symbol as in:-

	   pnmrotate -10 < turing.pgm > fred.pgm
	   usage:  pnmrotate [-noantialias] <angle> [pnmfile]

from the source:

    if ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' )
        {
        if ( pm_keymatch( argv[argn], "-antialias", 2 ) )
            antialias = 1;
        else if ( pm_keymatch( argv[argn], "-noantialias", 2 ) )
            antialias = 0;
        else
            pm_usage( usage );
        ++argn;
        }

    if ( argn == argc )
        pm_usage( usage );
    if ( sscanf( argv[argn], "%f", &fangle ) != 1 )
        pm_usage( usage );

It only checks the first flagged option, so if you want a negative angle,
you'll need to add a -antialias (yes, it's the default but...) followed
by the negative angle:

  pnmrotate -antialias -45 < {file}.ppm > {file}.ppm.rot

Bug?  nah :)

-robert
-- 
Robert Lau					213.740.2866
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