On 2015-08-28 09:58+0100 Phil Rosenberg wrote: > Hi Alan > I have just noticed there is a value PL_NOTSET. This is documented in > plsdidev as a value to pass in when you do not wish to set a value. I > wondered if this might be usefully used in plspage. It would be much > better than passing in 0 or using zero to represent unset particularly > for the location. Currently in plspage it is impossible to set the > location (xoff, yoff) to (0,0) or to tell if the location is supposed > to be zero or if it is just unset. > > Of course the upshot is that this is an API change that will probably > break all the drivers and some user code. Also the value of PL_NOTSET > of -42 is not ideal as it would be perfectly legal to have a position > of -42. Something like MIN_PLINT would be better.
Hi Phil: The current 0. for [xy]upi and 0 for [xy]length to signal those values are unset should remain unchanged since those values are invalid for upi and length. However, I agree that using 0 to signal [xy]offset is unset is far from ideal since that is not an invalid value and there is a similar objection to using PL_NOTSET for this purpose. > This is really just a mention, I'm not saying we should do it as the > cost is pretty high. But something to think about. The minimum possible PLINT is definitely an invalid offset value so I think your idea to use MIN_PLINT to signal [xy]offset is unset is a good one so long as you continue to use 0. for [xy]upi and 0 for [xy]length to signal those values are unset. Furthermore, I don't feel the cost of this backwards incompatible API change is very high since my guess is few users bother with getting/setting [xy]offset. So I think this change is fine if accompanied by the necessary documentation changes for plspage and plgpage, and an announcement in README.release concerning this (minor) backwards-incompatible change in our API. Thus, if nobody else objects, I suggest you search through our entire source tree for mentions of [xy]offset, plgpage, and plspage, and make this global MIN_PLINT change accordingly. 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); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); 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 __________________________ ------------------------------------------------------------------------------ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
