Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Dan Dye writes: > I don't use the z graphics buffer much but I've been dropped into the > deep end by my temp ION license. I have an image, 'picC' > > picC=congrid(pic,3,400,400) ;where 3=[r,g,b] > > normally, I would tv this image: > > tv, picC, true=1 > > but this returns only a small portion of the lower right corner of the > image with a strange interference pattern. I consulted the > Fanning/Lumley/RSI documentation and found that the z buffer doesn't > accept truecolor so I'm pretty amazed that I got anything plotted at > all. > > tv, picC[0,*,*] > gives me a nice pseudoColor of the first band and at the full size. > > How can I get this image tv'd as and rgb? If it were me, I'd be using TVImage or ImDisp, or one of those other programs you were reading about, since they all do this automatically. :-) Cheers, David -- David Fanning, Ph.D. Fanning Software Consulting Phone: 970-221-0438 E-Mail: david@dfanning.com Coyote's Guide to IDL Programming: http://www.dfanning.com/
Thanks David. I did glean from TVImage the "Color_Quan" function. ------------< snip >------------------- The COLOR_QUAN function quantizes a TrueColor image and returns a pseudo-color image and palette to display the image on standard pseudo-color displays. The output image and palette can have from 2 to 256 colors. COLOR_QUAN solves the general problem of accurately displaying decomposed, TrueColor images, that contain a palette of up to 224 colors, on pseudo-color displays that can only display 256 (or fewer) simultaneous colors. ------------< snip >------------------- tv, Color_Quan(picC,1,R,G,B,COLORS=255) This would seem to be the trick but the result looks poor compared to the truecolor image.... David W. Fanning <david@dfanning.com> wrote in message news:<MPG.1950152f3957eac9989682@news.frii.com>... > Dan Dye writes: > >> I don't use the z graphics buffer much but I've been dropped into the >> deep end by my temp ION license. I have an image, 'picC' >> >> picC=congrid(pic,3,400,400) ;where 3=[r,g,b] >> >> normally, I would tv this image: >> >> tv, picC, true=1 >> >> but this returns only a small portion of the lower right corner of the >> image with a strange interference pattern. I consulted the >> Fanning/Lumley/RSI documentation and found that the z buffer doesn't >> accept truecolor so I'm pretty amazed that I got anything plotted at >> all. >> >> tv, picC[0,*,*] >> gives me a nice pseudoColor of the first band and at the full size. >> >> How can I get this image tv'd as and rgb? > > If it were me, I'd be using TVImage or ImDisp, or > one of those other programs you were reading about, > since they all do this automatically. :-) > > Cheers, > > David
Dan Dye writes: > Thanks David. I did glean from TVImage the "Color_Quan" function. > > ------------< snip >------------------- > The COLOR_QUAN function quantizes a TrueColor image and returns a > pseudo-color image and palette to display the image on standard > pseudo-color displays. The output image and palette can have from 2 to > 256 colors. > > COLOR_QUAN solves the general problem of accurately displaying > decomposed, TrueColor images, that contain a palette of up to 224 > colors, on pseudo-color displays that can only display 256 (or fewer) > simultaneous colors. > ------------< snip >------------------- > > tv, Color_Quan(picC,1,R,G,B,COLORS=255) > > This would seem to be the trick but the result looks poor compared to > the truecolor image.... Well, in IDL (as in life) it is hard to have your cake and eat it too. Cheers, David P.S. Let's just say if your image has 16.7 million colors and you have to pick 224 to display it, compromises will have to be made. :-( -- David Fanning, Ph.D. Fanning Software Consulting Phone: 970-221-0438 E-Mail: david@dfanning.com Coyote's Guide to IDL Programming: http://www.dfanning.com/
"Dan Dye" <ddye@flenvironmental.org> wrote in message news:dfc65bba.0306101448.45816068@posting.google.com... > I don't use the z graphics buffer much but I've been dropped into the > deep end by my temp ION license. I have an image, 'picC' > > picC=congrid(pic,3,400,400) ;where 3=[r,g,b] > > normally, I would tv this image: > > tv, picC, true=1 > > but this returns only a small portion of the lower right corner of the > image with a strange interference pattern. I consulted the > Fanning/Lumley/RSI documentation and found that the z buffer doesn't > accept truecolor so I'm pretty amazed that I got anything plotted at > all. > > tv, picC[0,*,*] > gives me a nice pseudoColor of the first band and at the full size. > > How can I get this image tv'd as and rgb? Could you restate your problem in terms of what you are trying to achieve? I'm curious as to why you want to use the Z-buffer (I know nothing about ION). Any who is this Lumley person? Cheers, Liam. Practical IDL Programming http://www.gumley.com/
David W. Fanning writes: > P.S. Let's just say if your image has 16.7 million colors and > you have to pick 224 to display it, compromises will have to > be made. :-( I got to thinking about this after I wrote it. There actually *is* good news here. I was celebrating my 25th wedding anniversary yesterday and it occurred to me that the compromises you have to make to get your colors just about right are at least 10-fold less onerous than the compromises you have to make to keep a marriage together for a long time. :-) Cheers, David -- David W. Fanning, Ph.D. Fanning Software Consulting, Inc. Phone: 970-221-0438, E-mail: david@dfanning.com Coyote's Guide to IDL Programming: http://www.dfanning.com/ Toll-Free IDL Book Orders: 1-888-461-0155
David W. Fanning <david@dfanning.com> writes: > > I was celebrating my 25th wedding anniversary yesterday > and it occurred to me that the compromises you have to > make to get your colors just about right are at > least 10-fold less onerous than the compromises > you have to make to keep a marriage together for a > long time. :-) Does this work? MARRIAGE, DECOMPOSED=0 Craig -- ------------------------------------------------------------ -------------- Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response ------------------------------------------------------------ --------------
> Could you restate your problem in terms of what you are trying to achieve? > I'm curious as to why you want to use the Z-buffer (I know nothing about > ION). > > Any who is this Lumley person? Giam Lumley right? Oh, maybe not... Sorry Liam. From my very limited understanding of ION, it passes image information from IDL to the webpage via the Z buffer. If it is possible to use truecolor in ION generated images I would very much like to hear about it but I now have acceptable results by adding "cube=6" read_jpeg, fname, image24bit ;wedding day quality image image24bit = congrid(image24bit,3,400,400) loadct, 13 image8bit=Color_Quan(image24bit,1,R,G,B,COLORS=255, cube=6) TVLCT, r, g, b TV, image8bit ;image after 25 years of marriage -d