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Re: switching PS device from color to b/w? [message #31289 is a reply to message #31256]

Mon, 24 June 2002 10:19

nobody@nowhere.com (S is currently offline

nobody@nowhere.com (S
Messages: 55
Registered: July 2001

Member

I did try it, and it works, thanks again David :) ! However, it doesn't seem
documented well in my docs (5.2 Linux). I've used bits_per_pixel to increase
the color resolution, but never to reduce it. I tried bits_per_pixel=1, and
it's not equivalent to color=0, I still get color output in my PS files. I
actually am reading a true color image (3 channels) and I want to convert it to
greyscale when I write a postscript output. I can specify the size of the page
precisely in idl, so I've a routine to read images and write them to postscript
files with a specific size (no surrounding blank or white space), which most of
my other apps don't allow this freedom (they have fixed page sizes). I don't
know of a better way to do it, but I just found that once you've given the
/color directive to idl, it retains it, I needed a way to reset the ps device
to it's original state, which by default is black and white. device, color=0
will do it, device, /color, bits_per_pixel=1 doesn't. So they can't be equiv-
alent in practice, in theory it sounds like they should be. Maybe David can
explain why they're in not in practice?

On Mon, 24 Jun 2002 10:24:28 -0600, Ken Mankoff
<mankoff@I.HATE.SPAM.cs.colorado.edu> wrote: >
>
> On Sun, 23 Jun 2002, David Fanning wrote:
>> Steve Smith<steven_smith> (nobody@nowhere.com) writes:
>>
>>> Once I write a color image to the ps device (using set_plot,
>>> 'PS'), I cannot get the idl session to re-set to b/w, is there
>>> such a command? Right now I'm starting a second idl session and
>>> doing all the greyscale work there. Basically, I'd like to send an
>>> option like /nocolor to the ps device so it will stop making color
>>> postscript. Is there any such command? I'm using idl 5.2 :(
>>
>> I'd try this:
>>
>> DEVICE, Color=0
>>
>
> Hi David,
>
> What is the difference between:
>
> DEVICE, color=0
> and
> DEVICE, /color, bits_per_pixel=1
>
> Which is more appropriate? Is the only difference for those people who
> argue about black being a color vs. the lack of all colors?
>
> -k.
>
>

--
Steve S.

steve @ NOSPAM sorry i'm tired of spam
remove spaces, NOSPAM and you'll see there is no email address attached :( !

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[Message index]

		Re: switching PS device from color to b/w? By: David Fanning on Wed, 26 June 2002 10:00
		Re: switching PS device from color to b/w? By: Liam E. Gumley on Wed, 26 June 2002 09:02
		Re: switching PS device from color to b/w? By: David Fanning on Wed, 26 June 2002 08:10
		Re: switching PS device from color to b/w? By: David Fanning on Wed, 26 June 2002 08:06
		Re: switching PS device from color to b/w? By: nobody@nowhere.com (S on Mon, 24 June 2002 10:19
		Re: switching PS device from color to b/w? By: Ken Mankoff on Mon, 24 June 2002 09:24
		Re: switching PS device from color to b/w? By: nobody@nowhere.com (S on Mon, 24 June 2002 09:16
		Re: switching PS device from color to b/w? By: David Fanning on Sun, 23 June 2002 22:37
		Re: switching PS device from color to b/w? By: condor on Tue, 09 July 2002 17:03

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