# coyote: CGGREEK

- coyote/Graphics
- coyote/Utilities
- [Source code]

NAME

      cgGREEK

PURPOSE

      This function provides a device-independent way to ask for a Greek letter as
      a string that can be included, for example, in a plot title. It uses the Greek
      simplex font (!4) when used with Hershey fonts, and the Symbol font (!9) when
      used with PostScript or True-Type fonts. Selects the type of Greek character to
      return based on value of !P.FONT. Updated now to return the UNICODE values for
      Greek characters for those fonts that support them (Macintosh?).

AUTHOR

      FANNING SOFTWARE CONSULTING
      David Fanning, Ph.D.
      1645 Sheely Drive
      Fort Collins, CO 80526 USA
      Phone: 970-221-0438
      E-mail: david@idlcoyote.com
      Coyote's Guide to IDL Programming: http://www.idlcoyote.com/

CATEGORY

      Graphics, Utilities

CALLING SEQUENCE

      greekString = cgGreek(greekLetter)

RETURN VALUE

      greekString    A string that represents the Greek letter.

ARGUMENTS

      greekLetter:    The name of the Greek letter desired. A string. Default: 'alpha'.
                      Valid string names are the 24 characters of the Greek alphabet.
                         alpha        nu
                         beta         xi
                         gamma        omicron
                         delta        pi
                         epsilon      rho
                         zeta         sigma
                         eta          tau
                         theta        upsilon
                         iota         phi
                         kappa        chi
                         lambda       psi
                         mu           omega
                       Note that if the first letter of the name is capitalized, this is
                       the equivalent of setting the CAPITAL keyword.

KEYWORDRS

      CAPTIAL:        If this keyword is set, the captial Greek letter is returned rather
                      than the lowercase Greek letter. An alternative way of capitalizing
                      the letter is to make the first letter of the name an uppercase letter.
      EXAMPLE:        If this keyword is set, the names of the Greek characters and their
                      symbols are written out in the current graphics window.
      PS:             Normally, the PostScript version of the greek letter is returned if
                      the current device is PostScript and !P.Font is 0 or 1. But, the
                      PostScript version of the greek letter can be obtained at any time
                      and in any device, by setting this keyword.
      UNICODE:        If this keyword is set, the function returns the Unicode for the Greek
                      letter.

EXAMPLE

      Lowercase PSI:
         IDL> Plot, findgen(11), XTitle='This title contains ' + $
               cgGreek('psi') + ' as a Greek letter'
      Uppercase PSI:
         IDL> Plot, findgen(11), XTitle='This title contains ' + $
               cgGreek('Psi') + ' as a Greek letter'

NOTES

      See the following article for additional information:
           http://www.idlcoyote.com/ps_tips/greeksym.html

RESTRICTIONS

      For this program to work correctly on your graphics display, you should be using
      Hershey fonts (!P.Font=-1). It will work correctly in PostScript with either
      hardware fonts (!P.Font=0) or True-Type fonts (!P.Font=1).

MODIFICATION HISTORY

      Written by: David W. Fanning, 9 January 2010.
      An alternative way to get an uppercase letter is to make the first letter of
         the Greek name uppercase. (Maarten Sneep's suggestion!) 11 Jan 2010. DWF
      Had the wrong value for the PostScript version of Phi. 26 January 2010. DWF
      Added UNICODE keyword and values for Greek characters. 11 June 2010. DWF.
      Changed the branching from !D.NAME EQ 'PS' to !P.FONT NE -1. (This is actually
          what the documentation says, and what I intended.) 13 Dec 2010. DWF.
      I don't think the last change did quite want I wanted. More tweaking to make
          this more responsive to being in a PostScript file. 31 July 2011. DWF.
      Added PS keyword so the return value is the PostScript file. This is for
          convenience only, as the return value will be the PostScript value if
          the current graphics device is PS and FONT is not equal to -1. 30 Aug 2011. DWF.
      Retired Greek and replaced by cgGreek. 23 Dec 2012. DWF.