| Re: can't change colortable in current window (linux bpp24) [message #16278] |
Fri, 16 July 1999 00:00 |
J.D. Smith
Messages: 214
Registered: August 1996
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Senior Member |
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Liam Gumley wrote:
>
> "J.D. Smith" wrote:
>> Sadly, the most popular X servers for Linux (XFree86) do not support
>> overlays... I.E. they can't do PseudoColor when running in TrueColor
>> mode. Version 4.0 will add this feature, but it is far from ready.
>
> That's interesting. I based my comments on my experience with SGI, which
> allows PseudoColor or TrueColor modes to be used when you have 24-bit
> hardware. I guess that to use IDL PseudoColor mode, you'd need to
> restart your X server in 8-bit mode. Could you remind us of the syntax?
> In addition, are there any other Linux X servers which do provide this
> capability?
>
startx -- -bpp 32
or, if you're using xdm, you'll need to edit your "Xservers" file to
contain -bpp 32.
I believe Xi graphics makes a product called AccelX which purports to do
overlays. I've never seen that for myself, but they claim it's true
(http://www.xigraphics.com/). Let me know if you find anything out.
JD
--
J.D. Smith |*| WORK: (607) 255-5842
Cornell University Dept. of Astronomy |*| (607) 255-6263
304 Space Sciences Bldg. |*| FAX: (607) 255-5875
Ithaca, NY 14853 |*|
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| Re: can't change colortable in current window (linux bpp24) [message #16281 is a reply to message #16278] |
Fri, 16 July 1999 00:00  |
David R. Klassen
Messages: 14
Registered: December 1996
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Junior Member |
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To control which mode your X server begins in under Linux:
startx -- -bpp #
Where # is the number of bits per pixel you wish. All of
this is assuming you have defined the particular color-depth
in your XF86Config file.
Liam Gumley wrote:
>
> "J.D. Smith" wrote:
>> Sadly, the most popular X servers for Linux (XFree86) do not support
>> overlays... I.E. they can't do PseudoColor when running in TrueColor
>> mode. Version 4.0 will add this feature, but it is far from ready.
>
> That's interesting. I based my comments on my experience with SGI, which
> allows PseudoColor or TrueColor modes to be used when you have 24-bit
> hardware. I guess that to use IDL PseudoColor mode, you'd need to
> restart your X server in 8-bit mode. Could you remind us of the syntax?
> In addition, are there any other Linux X servers which do provide this
> capability?
>
> Cheers,
> Liam.
>
> --
> Liam E. Gumley
> Space Science and Engineering Center, UW-Madison
> http://cimss.ssec.wisc.edu/~gumley
--
David R. Klassen
Department of Chemistry & Physics
Rowan University
201 Mullica Hill Road
Glassboro, NJ 08028
856-256-4500 x3273
http://elvis.rowan.edu/~klassen/
klassen@rowan.edu
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| Re: can't change colortable in current window (linux bpp24) [message #16282 is a reply to message #16278] |
Fri, 16 July 1999 00:00 |
Liam Gumley
Messages: 473
Registered: November 1994
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Senior Member |
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"J.D. Smith" wrote:
> Sadly, the most popular X servers for Linux (XFree86) do not support
> overlays... I.E. they can't do PseudoColor when running in TrueColor
> mode. Version 4.0 will add this feature, but it is far from ready.
That's interesting. I based my comments on my experience with SGI, which
allows PseudoColor or TrueColor modes to be used when you have 24-bit
hardware. I guess that to use IDL PseudoColor mode, you'd need to
restart your X server in 8-bit mode. Could you remind us of the syntax?
In addition, are there any other Linux X servers which do provide this
capability?
Cheers,
Liam.
--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley
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| Re: can't change colortable in current window (linux bpp24) [message #16285 is a reply to message #16278] |
Fri, 16 July 1999 00:00 |
J.D. Smith
Messages: 214
Registered: August 1996
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Senior Member |
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Liam Gumley wrote:
>
> Olivier ARCHER wrote:
>> when i load a color table with loadct *after* opening a window, nothing
>> happen. here a piece of code producing the error:
>>
>> device,decompose=0
>> window,/free && tv,dist(400) ;; picture in B/W
>> loadct,4 ;; this have no effect in the current
>> window ( no error messages )
>> window,/free && tv,dist(400) ;; picture in color; loadct effect...
>>
>> this fail on a linux rh6 , with dpyinfo saying that my X serveur is
>> TrueColor, with 24 plane depth
>> this work on solaris( creator 3D graphics card) , with dpyinfo saying
>> that my X serveur support various combination of class/depth.
>
> Olivier,
>
> The behavior you describe is actually a *feature* of 24-bit TrueColor
> mode in IDL. You can certainly do a lot of neat stuff in 24-bit mode, as
> described David's excellent articles. A quick way around this problem in
> 24-bit mode is to always load the color table just before displaying the
> image, e.g.
>
> loadct, 4
> tvscl, dist(256)
>
> However if you really *want* all of your graphics displays to update
> automatically any time you change the color table (using LOADCT,
> XLOADCT, or TVLCT), *and* you don't mind the limitations of 8-bit
> PseudoColor mode in IDL, then type the following commands just after
> starting a new IDL session:
>
> device, pseudo=8, decomposed=0, retain=2 ; select PseudoColor mode
> window, /free, /pixmap ; lock this mode by opening a window
> wdelete, !d.window
>
Sadly, the most popular X servers for Linux (XFree86) do not support
overlays... I.E. they can't do PseudoColor when running in TrueColor
mode. Version 4.0 will add this feature, but it is far from ready.
JD
--
J.D. Smith |*| WORK: (607) 255-5842
Cornell University Dept. of Astronomy |*| (607) 255-6263
304 Space Sciences Bldg. |*| FAX: (607) 255-5875
Ithaca, NY 14853 |*|
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| Re: can't change colortable in current window (linux bpp24) [message #16287 is a reply to message #16278] |
Fri, 16 July 1999 00:00 |
Liam Gumley
Messages: 473
Registered: November 1994
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Senior Member |
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Olivier ARCHER wrote:
> when i load a color table with loadct *after* opening a window, nothing
> happen. here a piece of code producing the error:
>
> device,decompose=0
> window,/free && tv,dist(400) ;; picture in B/W
> loadct,4 ;; this have no effect in the current
> window ( no error messages )
> window,/free && tv,dist(400) ;; picture in color; loadct effect...
>
> this fail on a linux rh6 , with dpyinfo saying that my X serveur is
> TrueColor, with 24 plane depth
> this work on solaris( creator 3D graphics card) , with dpyinfo saying
> that my X serveur support various combination of class/depth.
Olivier,
The behavior you describe is actually a *feature* of 24-bit TrueColor
mode in IDL. You can certainly do a lot of neat stuff in 24-bit mode, as
described David's excellent articles. A quick way around this problem in
24-bit mode is to always load the color table just before displaying the
image, e.g.
loadct, 4
tvscl, dist(256)
However if you really *want* all of your graphics displays to update
automatically any time you change the color table (using LOADCT,
XLOADCT, or TVLCT), *and* you don't mind the limitations of 8-bit
PseudoColor mode in IDL, then type the following commands just after
starting a new IDL session:
device, pseudo=8, decomposed=0, retain=2 ; select PseudoColor mode
window, /free, /pixmap ; lock this mode by opening a window
wdelete, !d.window
PseudoColor mode will then be locked in for the rest of the IDL session
(you can't change modes once you've created a graphics window). To check
that you actually got PseudoColor mode:
device, get_visual_name=mode
print, mode
If you want to change back to TrueColor mode in future IDL sessions,
replace 'pseudo=8' with 'true=24'. These commands are best placed in an
IDL startup file. Type
? startup
in IDL to find out how to use a startup file.
Cheers,
Liam.
--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley
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