This subject has been discussed many times on this list. Recently, I tested ideas from http://archives.seul.org/geda/user/Jan-2009/msg00869.html and this resulted in a patchset 2684726 at https://sourceforge.net/tracker/index.php?func=detail&aid=2684726&group_id=73743&atid=538813
Of course, this is of very limited use, but somebody may be interested. General features First patches introduce multiple fonts per board; every text has a pointer to it's font; the font for a new text is selected in the text input window; I also added a field for the font scale. Then different text layouts are introduced. Texts may be vertical or horizontal; the layout also may be `reverse': for horizontal layouts this means right-to-left; for vertical --- donwside-up. (http://ineiev.users.sourceforge.net/pcb/graph/layout.png) (the figure shows an optimistic case for a horizontal font turned vertically: in general, the letters are not adjusted horizontally). A new font type added, based on FreeType2 library. TTF and Type1 fonts seem to work, PCF don't (most probably, I load them incorrectly). The glyphs are loaded and rendered in DrawTextLowLevel() function; perhaps some caching could improve performance, but this is a _simple_ implementation. Kerning should work for horizontal layouts (http://ineiev.users.sourceforge.net/pcb/graph/kerning.png) FreeType does not support kerning for vertical layouts, and actually I have no idea if the implementation may be used for such scripts. Glyphs rendering At first I rendered them with `vertical' lines, like this: (http://ineiev.users.sourceforge.net/pcb/graph/fill.png) This was the most simple way, though small characters become unreadable too soon. Then I learnt FreeType glyphs had outline structures and drew them with lines: (http://ineiev.users.sourceforge.net/pcb/graph/outline.png) The next way was to join outlines with fills: (http://ineiev.users.sourceforge.net/pcb/graph/full.png) The `vertical' lines don't fill the outlines very good, some small spaces remain; probably, something should be adjusted. At last, I tried to do it with polygons: (http://ineiev.users.sourceforge.net/pcb/graph/poly.png) I don't do it clearly, because some contours need to be added, other subtracted, and it is not evident to me how to do it in real time. Besides that, I think lines look more realistic, because the polygons are not restricted with design rules; the lines are. Cyrillic texts The latest example demostrated a Cyrillic font; the implementation matches this script quite well; some fonts lacked `ж' glyph; no other inconveniences. Polytonic Greek (http://ineiev.users.sourceforge.net/pcb/graph/grdjvu.png) There may be some problems: first, the implementation does not support combining characters, so there may be difficulties when entering accented letters; I entered them via Gnome character map application. Also, once I could not pull `μ' glyph from a font, though it was present; probably something wrong with that font mapping. Devanagari (http://ineiev.users.sourceforge.net/pcb/graph/devanagari.png) The consonants are not joined into ligatures (this was expected); however, it puts viramam where it makes sence; it even adds vowels (much better than I expected). `i short' is put in a wrong place: I actually wrote an incorrect sequence to force it hang where it should, e.g. "-ko(i)va-" instead of "-kovi-". Afro-Asiatic scripts (http://ineiev.users.sourceforge.net/pcb/graph/ar.png) I really can't tell how usable it is for tfel-ot-thgir scripts; I reproduced a word, I don't know how correctly. I checked "reverse" checkbox in the text input window and dragged the letters from Gnome character map. Some letters take several places in the map; my font accepted one of them and rejected the rest. Some notes on usage To load a font, use LoadFreetype action, like this: LoadFreetype(some_font.pfb); it will be added to the font list of the current board. Every font in the list has use counter, it will be embedded when saving the board if some texts use it. Different rendering options (outlines, fill, polygons) are switched with defines in src/ft2font.c Final remarks Once I thought whether it would be better to use pango instead of freetype; it would solve problems with combining character, but it has the next disadvantages: first, it is a stronger dependence; second, it renders to bitmaps only, whereas having vectored outlines is important when the characters grow small. As I mentioned, these patches can hardly be used in practice, because I had to change PCB file format, so mainstream PCB won't read the files saved by the patched program. Regards, Ineiev _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
