Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
On Feb 8, 4:48 pm, bing999 <thibaultga...@gmail.com> wrote: > Hi, > > I want to overplot symbols (filled circles) on a previously drawn > figure. To make it easier to read, I would like to make the symbols > transparent. > Is there a way to do that? > > Thanks a lot! > > cheers And please note that I would like to save the plot in PostScript... :)
Am 08.02.2011 16:48, schrieb bing999: > Hi, > > I want to overplot symbols (filled circles) on a previously drawn > figure. To make it easier to read, I would like to make the symbols > transparent. > Is there a way to do that? > > Thanks a lot! > > cheers have you asked your supplier? 8)
bing999 writes: > I want to overplot symbols (filled circles) on a previously drawn > figure. To make it easier to read, I would like to make the symbols > transparent. > Is there a way to do that? I guess if you were willing to fool around long enough, you could do this with a combination of Make_Transparent_Image and cgImage. If it were me, I don't think I would bother. :-) Cheers, David -- David Fanning, Ph.D. Fanning Software Consulting, Inc. Coyote's Guide to IDL Programming: http://www.idlcoyote.com/ Sepore ma de ni thui. ("Perhaps thou speakest truth.")
On 2/8/11 8:48 AM, bing999 wrote: > Hi, > > I want to overplot symbols (filled circles) on a previously drawn > figure. To make it easier to read, I would like to make the symbols > transparent. > Is there a way to do that? The new graphics, iTools, and object graphics systems can do this. What do you mean by "previously drawn figure", i.e., how did you make the previously drawn figure? Mike -- www.michaelgalloy.com Research Mathematician Tech-X Corporation
On Feb 8, 10:10 am, bing999 <thibaultga...@gmail.com> wrote: > On Feb 8, 4:48 pm, bing999 <thibaultga...@gmail.com> wrote: > >> Hi, > >> I want to overplot symbols (filled circles) on a previously drawn >> figure. To make it easier to read, I would like to make the symbols >> transparent. >> Is there a way to do that? > >> Thanks a lot! > >> cheers > > And please note that I would like to save the plot in PostScript... :) While the new IDL graphics system has the capability to produce transparent symbols etc, you still can't save the plot directly into a postscript format (transparent regions will become opaque). You will have to first save the plot in a png format and then convert to ps/ eps. Overplotting on a previously-drawn image is a whole different issue. Either ask the "supplier" (as Reimar suggested) or extract the data from the plot using something like Dexter (http://dc.zah.uni- heidelberg.de/dexter/ui/ui/custom/).
On Feb 8, 8:10 am, bing999 <thibaultga...@gmail.com> wrote: > On Feb 8, 4:48 pm, bing999 <thibaultga...@gmail.com> wrote: > >> Hi, > >> I want to overplot symbols (filled circles) on a previously drawn >> figure. To make it easier to read, I would like to make the symbols >> transparent. >> Is there a way to do that? > >> Thanks a lot! > >> cheers > > And please note that I would like to save the plot in PostScript... :) Yes, I should add this is actually a limitation in PostScript itself, it just can't do (semi-)transparency of vector objects. It can do transparency of rasters, in a limited way, but that's the same as you making the plot in PNG with an alpha channel and then converting to PS. I see a lot of new graphics packages advertise writing directly in PDF, and PDF is apparently capable of handling semi-transparent objects. I see that IDL 8.0 can output to PDF as well, now they just need to provide support for semi-transparent objects. Useful and/or interesting information here: https://secure.wikimedia.org/wikipedia/en/wiki/Transparency_ %28graphic%29
On Feb 8, 11:10 am, bing999 <thibaultga...@gmail.com> wrote: > On Feb 8, 4:48 pm, bing999 <thibaultga...@gmail.com> wrote: > >> Hi, > >> I want to overplot symbols (filled circles) on a previously drawn >> figure. To make it easier to read, I would like to make the symbols >> transparent. >> Is there a way to do that? > >> Thanks a lot! > >> cheers > > And please note that I would like to save the plot in PostScript... :) What about reading the RGB pixel values in the place you need the symbols, add 32 (or another suitable value) to the R channel while leaving the G and B channels untouched. That will create a red-hued semi-transparent symbol... Ciao, Paolo