I have noticed during some of my recent tests of PLplot line styles that the PostScript graphics results looked better using the ImageMagick "display" application than they do with the "gv" Postscript viewer. My understanding is that "display" simply uses a front-end to ghostscript to view PostScript files and gv itself is also a frontend to ghostscript. Thus, my working hypothesis to explain the difference in viewed results was that "gv" by default was setting worse ghostscript parameters than "display". After a lot of experimentation, I finally found that I could improve the "gv" results to be consistent with what you get with "display" if I used the following gv option:
--arguments="-dGraphicsAlphaBits=4" which instructs ghostscript to use full antialiasing capability for graphics. If I use the following gv option instead: --arguments="-dTextAlphaBits=4 -dGraphicsAlphaBits=4" I get results that are identical to those I see with the first form of the arguments option which implies that gv defaults to telling ghostscript to use full antialiasing for text. But apparently for unknown reasons it does not specify full antialiasing for graphics (as opposed to text) by default which is why you have to set the --arguments="-dGraphicsAlphaBits=4" option to get such antialiasing. I have been using gv for many years with some dissatisfaction over the quality of the rendered graphics so I was very happy to (finally) find this solution. I hope this information is useful to others here that are using gv to evaluate the quality of the PostScript results produced by PLplot. I did the above tests with PostScript results generated by -dev epsqt, but I assume it would be the same for any of our many PostScript devices. In case these interesting gv rendering improvements depend on gv or ghostscript version, I am using version 1:3.7.1-1 of the Debian stable gv package and version 8.71~dfsg2-9 of the Debian stable ghostscript package. That Debian package of ghostscript is for the "GPL" flavour of ghostscript. I think that is the dominant flavour now, but I mention it because in the old days on Debian there were several ghostscript flavours you could choose from. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); PLplot scientific plotting software package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
