oooooo, sounds like exactly what i want! thanks! -m
On Tue, Jan 22, 2013 at 4:13 PM, Greg Snow <[email protected]> wrote: > If you want to convert between different units using base graphics then look > at the grconvertX and grconvertY functions (in the graphics package). These > functions will convert from/to user coordinates, inches, device, figure, and > plot coordinates. So you could use grconvertX to find out what user value > on the x scale to give to draw.circle that would then generate a circle with > a given size in inches, or relative to the device, figure, or plotting > region. > > > On Sun, Jan 20, 2013 at 2:59 PM, Murat Tasan <[email protected]> wrote: >> >> hi all - i'm having some difficulty figuring out how to convert >> between "user units" (which i can't find a definition for in the >> plotrix package) and either (a) device units (e.g. inches with PDFs) >> or (b) user coordinates along any particular axis. >> >> as an example, suppose i set up a PDF device with inches, the device >> has both outer and inner magins, and the plot region has drastically >> different x and y coordinate ranges (e.g. xlim = c(0, 1), ylim = c(0, >> SOME_VERY_LARGE_NUMBER)). >> >> now i'd like to draw.circle(...) but i can't figure out what units the >> radius argument takes. >> "user units" doesn't appear to be inches in this case, and it it >> corresponds to user coordinates, i don't know which axis' scaling is >> to be used as the reference. >> >> ideally, one would be able to specify the radius in user coordinates >> while specifying _which_ axis to use as the standard (e.g. an axis = >> "y" or axis = "x" argument). >> >> getFigCtr(...) can help in figuring this out, but its argument takes >> the relative position of the "figure" region, rather than the "plot" >> region, which is more apt for properly placing shapes. >> >> i know the grid package has extensive unit conversion code, but i'm >> trying to update a series of figures using only base graphics... >> >> i can't seem to find a rigorous definition of "user units" anywhere in >> the plotrix package. >> anyone know of where i can find this info? >> >> cheers, >> >> -m >> >> ______________________________________________ >> [email protected] mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > > > > -- > Gregory (Greg) L. Snow Ph.D. > [email protected] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
