Re: 1 bit RGB image representation problem

From	Carlos <angus@quovadis.com.ar>
Newsgroups	comp.lang.postscript
Subject	Re: 1 bit RGB image representation problem
Date	2016-06-30 12:19 +0200
Organization	A noiseless patient Spider
Message-ID	<nl2ro6$4nt$1@dont-email.me> (permalink)
References	(1 earlier) <875df2f7-19a0-4103-8f46-a81093e1b118@googlegroups.com> <fca1ed29-394c-4ced-9b22-99a5d8df8112@googlegroups.com> <4dcf1d03-0b39-44a4-9c4e-c716ba1d1d44@googlegroups.com> <8048fb28-42ab-4325-9870-d30c5542a356@googlegroups.com> <e249e657-680b-4ca2-ad38-b2da78cd0121@googlegroups.com>

Show all headers | View raw

On 30/06/2016 2:15, luser droog wrote:
[...]
> Yes, that's roughly what I was thinking. I think the last byte of
> each row will need to be padded with zero bits. So if your image
> was 6x4, it would be laid out like this:
>
>    rgbrgbrg brgbrgbr gb000000
>    rgbrgbrg brgbrgbr gb000000
>    rgbrgbrg brgbrgbr gb000000
>    rgbrgbrg brgbrgbr gb000000
>
> But I still haven't found any specific documentation that speaks
> to this. So, it still might not work. :/

It does work that way, at least in Ghostscript.

     %!PS

     /to_s {
         dup length dup string 0 1  4 -1 roll 1 sub {
             3 copy exch pop get
             3 copy put pop pop
         } for
         exch pop
     } def

     /img <<
         /ImageType 1
         /Width     3
         /Height    3
         /ImageMatrix [ 3 0 0 -3 0 3 ]
         /DataSource [
         % col [0][1][2   ][pad  ]
             2#11111010 2#10000000
             2#10001101 2#00000000
             2#00100011 2#10000000
         ] to_s
         /BitsPerComponent 1
         /Decode [ 0 1 0 1 0 1 ]
     >> def

     gsave
       /DeviceRGB setcolorspace
       200 200 translate
       100 100 scale
       img image
     grestore

     showpage

--

Back to comp.lang.postscript | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

1 bit RGB image representation problem bhor.pranjal@gmail.com - 2016-06-23 05:01 -0700
  Re: 1 bit RGB image representation problem luser droog <luser.droog@gmail.com> - 2016-06-23 21:02 -0700
    Re: 1 bit RGB image representation problem bhor.pranjal@gmail.com - 2016-06-24 21:22 -0700
      Re: 1 bit RGB image representation problem luser droog <luser.droog@gmail.com> - 2016-06-24 22:51 -0700
        Re: 1 bit RGB image representation problem bhor.pranjal@gmail.com - 2016-06-25 00:00 -0700
          Re: 1 bit RGB image representation problem luser droog <luser.droog@gmail.com> - 2016-06-29 17:15 -0700
            Re: 1 bit RGB image representation problem Carlos <angus@quovadis.com.ar> - 2016-06-30 12:19 +0200

csiph-web