I am transferring this discussion from plplot-general to plplot-devel with a different subject.
On 2010-09-09 10:36-0400 Hezekiah M. Carty wrote: > The OCaml bindings include a character_height function which (should?) > return the character height in world coordinates: > > http://plplot.svn.sourceforge.net/viewvc/plplot/trunk/bindings/ocaml/plplot.ml?revision=11020&view=markup > > The function begins on line 611 and should be fairly self-explanatory. > There is likely a simpler way to do this using internal PLplot > functions, but this method allows you to stick to the public, > documented API. > I am not that good at reading OCaml code, but it looks like the method combines results from plgch, plgvpd, plgspa, and plgvpw. From the documentation of those, you should be able to use the combination of plgspa and plgvpd to obtain the viewport limits in mm. Then combine those results with plgvpw results (which obtains the viewport limits in world coordinates) to determine the ratio of world coordinates to mm in the y direction. Then use that factor to transform plgchr height results in mm to world coordinates. So I think this idea should work fine, but it would not be necessary if we had a central libplplot pllegend capability which simply accessed the required internal variables directly. I have brought up the central legend-drawing topic because I noticed plplot.ml contained the draw_legend function which uses the result from the character_height function beginning on line 611 to draw a legend. The octave interface also has a legend-drawing capability, and it appears that the original poster on plplot-general also has a need for that capability in Perl/PDL. If not obvious already, it appears from all these lines of evidence that PLplot needs a legend-drawing capability in its core library. Hez, from your OCaml experience with legends would you be willing to implement a legend-drawing capability in libplplot and also modify one of our C examples to use that new API? (I assume from here on that that new function would be called pllegend.) If you were willing to do that implementation, I (and presumably others from past history) would be willing to help out afterward with the usual API addition tasks of pllegend documentation and propagating the pllegend API and its use in a standard example to all our languages. I believe the ultimate result of a well-documented and uniform pllegend capability for all our languages would be a welcome improvement to PLplot. 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 __________________________ ------------------------------------------------------------------------------ This SF.net Dev2Dev email is sponsored by: Show off your parallel programming skills. Enter the Intel(R) Threading Challenge 2010. http://p.sf.net/sfu/intel-thread-sfd _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
