How to use Tibetan fonts and keyboard map in Yudit Original: Gregory Mokhin 2002-10-10 Last modified: 2003-08-03 Tibetan support in Yudit is still at beta stage, however it can be useful both for testing purposes and for typing many Tibetan texts using Unicode. You can type Tibetan using Wylie transliteration and you will have proper conversion to Unicode symbols as you type. In case you have an OpenType font, you will have proper display of the majority of Tibetan glyphs, including very complex Tibetan-Sanskrit stacks. But you may still see something unexpected. Introduction Yudit ( http://www.yudit.org ) is a free Unicode editor which can be applied to editing text in Tibetan script (including Tibetan proper and Dzongkha, used mainly in Bhutan). Pre-requisites 1. Download the latest version of Yudit from http://www.yudit.org and follow the installation instructions. 2. Download utibetan.ttf font from *** and copy it into the /usr/share/yudit/fonts or ~/.yudit/fonts UTibetan.ttf font is available under GPL. It was developed by Gregory Mokhin, based on the glyph outlines of the LTibetan.ttf font by Pierre Robillard, who had designed LTibetan and had made it available under GPL (see http://www.interlog.com/~pierrer). 3. There are OpenType Tibetan fonts available elsewhere, but they are not yet supplied with this distribution due to unclear licensing issues. Configuration After installing Yudit and the fonts you need to configure the fonts. First invoke and exit Yudit. This will create a ~/.yudit/yudit.properties file. Edit the font property in this file to add your Tibetan font, for instance: yudit.font.TrueType=arial.ttf,utibetan.ttf ... Add OpenType font to this line if you have one. Select Tibetan for input in the Yudit GUI. This is a clustering kmap, which means that a whole cluster needs to be entered to get proper shaping. Tibetan text rendering It is important to keep in mind the difference between proper encoding of a text (i.e., correct Unicode values for the typed letters and syllables) and proper rendering and display of the text by a word processor. Yudit is capable of using glyph substitution and positioning required for proper display of Tibetan, but only when the font itself has OpenType tables (technically speaking, GSUB and GPOS) and the other OpenType features necessary for the rendering engine to work properly (see the Appendix). Utibetan.ttf is an incomplete version of the font. It contains the glyphs for the basic Unicode points for Tibetan but lacks the OpenType features necessary for proper Tibetan support. These features are currently under development. There exist other Tibetan fonts that do support OpenType features, and Tibetan texts typed in Yudit will be displayed properly with these fonts (when/if these fonts become available for public download by their authors). Typing Tibetan Use Wylie transliteration to type Tibetan. For example, try typing ye shes mig gcig dri ma med to see what manifests. To learn the Wylie transliteration system for Tibetan, one may consult an excellent document prepared by Prof. David Germano and THDL team, http://www.thdl.org, which presents both the original Wylie scheme and their extensions to classic Wylie, called "Extended Wylie." See http://iris.lib.virginia.edu/tibet/tools/ewts.pdf (but note the errata at http://sourceforge.net/tracker/index.php?func=detail&aid=646583&group_id=61934&atid=502515). Thanks to David Chandler for informing me about this.) Note that there is still no consensus regarding a standardized set of extensions to classic Wylie transliteration. However, the differences mainly concern Tibetanized Sanskrit stacks and mantras and punctuation details. Modifying Tibetan kmap If you modify the Tibetan-Wylie.kmap to your needs, you should compile it as follows: $ mytool -convert my -write Tibetan-Wylie.my -kmap Tibetan-Wylie.kmap and substitute the original Tibetan-Wylie.my file coming with Yudit distribution by the compiled Tibetan-Wylie.my file. Please send your comments to the Yudit developers and to me. Gregory Mokhin, Moscow, 03 August 2003 ================================================= Appendix: Technical notes In addition to the general flow of text from left to right, a number of Tibetan letters may also be combined from top to bottom, and the Unicode chart for Tibetan does attempt to take into account this property of Tibetan writing. Unfortunately, the existing Unicode chart for Tibetan is not sufficient for proper display of all Tibetan syllables, and, similar to Indic scripts, requires OpenType glyph substitution and positioning tables to be implemented and applied for proper font rendering. Different variants of subjoined letters should be used for different initial syllables. For example, the "r" in "kr", "khr", "tr", "thr" should represent different variants of subjoined "r", because the vertical position in the syllable with respect to the baseline depends on the initial (upper) part of the syllable. The same is true for subjoined "ya", "wa", and "u". One should also take into account the variations in vertical positioning of the elements mantric syllable stacks, which were originally borrowed from Sanskrit and are quite common in Tibetan texts. In fact, OpenType support for Tibetan is simpler than for Indic scripts. The main registered OpenType layout features needed to support Tibetan script are: 'ccmp', 'blws', 'abvs' - all belonging to GSUB (glyph substitution) 'blwm', 'abvm', 'kern' - all GPOS (glyph positioning)