Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Klaus Bramstedt wrote: > I have to plot TrueColor pictures in IDL. These pictures contain colors > defined as RGB-values. On a TrueColor X-Display everything works fine > with about 16 million colors, i get very nice pictures. I want to plot > this pictures on a PostScript color printer. But the 'ps' device in IDL > only allows 256 colors, which is definitily too less for my pictures. > Has someone any idea, how to put my pictures on paper? See the IDL Reference Manual section on 'The Postscript Device', in particular the section on 'True-Color Images', which says in part (begin quote) Use the TRUE keyword to the TV and TVSCL procedures to indicate that the image is a true-color image and to specify the dimension over which color is interleaved. A value of 1 specifies pixel interleaving, 2 is row interleaving, and 3 is image interleaving. The following example writes a 24-bit image, interleaved over the 3rd dimension, to a PostScript file: SET_PLOT, 'PS' ;Set the PostScript device to *8* bits per color, not 24: DEVICE, FILE='24bit.ps', /COLOR, BITS=8 TV, [[[r]], [[g]], [[b]]], TRUE=3 DEVICE, /CLOSE (end quote)
Klaus Bramstedt <bram@gome5.physik.uni-bremen.de> writes: > I have to plot TrueColor pictures in IDL. These pictures contain colors > defined as RGB-values. On a TrueColor X-Display everything works fine > with about 16 million colors, i get very nice pictures. I want to plot > this pictures on a PostScript color printer. But the 'ps' device in IDL > only allows 256 colors, which is definitily too less for my pictures. > Has someone any idea, how to put my pictures on paper? (posted and emailed) I'm not sure, but I do the following to get a color postscript file from the image stored in the Zbuffer. What happens if you change the bits from 8 to something larger? It might be worth a try. But I would hope that 2^{24} colors would be enough (for 8 bit colors, each color coordinate can range from 0 to 255, so the total palette contains 16,777,216 colors. See page 16-7 in the IDL User's Guide.). SET_PLOT, 'Z', /copy ;copy the device's internal color table a = TVRD() SET_PLOT, 'PS', /copy fn = '/home0/amara/temp.ps' DEVICE, filename=fn, /color ,/landscape, bits=8 TV, a DEVICE, /close Amara -- ************************************************************ ************* Amara Graps email: agraps@netcom.com Computational Physics vita: finger agraps@best.com Multiplex Answers URL: http://www.amara.com/ ************************************************************ *************