Copyright 2007 TeX Users Group. You may freely use, modify and/or distribute this file. More problems with `invisible ink' and with repeat encodings: ============================================================= ATM for Windows cannot handle multiple encodings, that is, one character name listed under two or more character codes in the encoding vector (Which is something that works just fine in ATM for Macintosh, as well as all PS interpreters, and all PS clones). One aspect of this problem is that a character can only be referenced using the first mentioned character code in the encoding vector. Which is a major problem with some fonts, and requires reorganizing the listing of the encoding vector in the font, as well as rewriting Windows software to carefully remap character codes to the ones that ATM happens to like. But there is a second problem. If you use one of the character codes other than the first one, you get `invisible ink'. The rest of the text string is blanked out from there on. That is, this character code is NOT even linked to /.notdef, which is what one might hope for. For example, suppose the encoding vector contains the following: . . dup 195 /space put . . dup 32 /space put . . Then you can get a `space' when you use character code 195, and you don't get a space when you use the space bar. Bad enough. But worse, typing `abcdefghijkl' yields only `abcdef' on screen! So why use repeated encoding in the first place? ================================================ Most MS Windows (and Macintosh) applications cannot handle character codes in the `control character' range 0 -- 31. And many existing fonts have characters in that range. To make these fonts useable with MS Windows (and Macintosh) applications, without disrupting their current users, one can add repeated encodings, for the `control characters'. This is, for example, used with Adobe Lucida Math fonts. For use with TeX, these fonts need to have characters in the control character range. But these cannot be accessed from most other applications. So the control character range is remapped to 161 - 170 and 172 - 195.