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.