On 2008-03-08 23:48-0500 Hezekiah M. Carty wrote: > In its current form, plimage automatically scales the plotted colors > to take advantage of as much dynamic range in the color scale 1 as > possible - the minimum value in the given image corresponds to a color > of 0.0 and the maximum value in the image corresponds to a color of > 1.0. > > The attached patch adds two extra parameters to plimage to allow a > user to set this range on their own. Image values of valuemin or less > will now map to color 0.0 and image values of valuemax or greater will > map to color 1.0. Values between valuemin and valuemax will similarly > map to colors between 0.0 and 1.0, in the same way plimage currently > handles this. > > The reason for this change is to allow multiple plots to be made with > varying data sets, while maintaining directly comparable color scales > between plots. The current implementation does not allow this for > data sets with different value ranges without manually setting at > least one pixel to a fixed minimum value and another to a fixed > maximum value in each image. > > This patch affects include/plplot.h and src/plimage.c and should apply > cleanly against the current PLplot Subversion head. I have not made > any adjustments to any of the included language bindings as I want to > find out if this is an acceptable API change, if I should make this in > to a new function instead. I think it is a worthwhile adjustment to > plimage, particularly given that it is an undocumented function, > except for the code and an example.
The lack of plimage documentation is an oversight. Thanks for pointing out that issue. I would encourage you to submit a patch for doc/docbook/src/api.xml to add documentation for plimage (and also your modified version of it, see next). I think a variation of plimage with a user-specified colour range is worth having, but to preserve backwards API compatibility you should rename your modified version to something else and reimplement plimage as a wrapper so it has the same arguments as now, derives the minimum and maximum of the colour range, then calls plimagef to do the rest. I would encourage you to modify your present patch to that effect. 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 email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
