Creating a Opentype font for Brahmi

[virtualvinodh]

Hi All,

I have been working on creating a font for Brahmi. I have add the necessary glyph imported through font creator. I am now working on creating the opentype rules for the font rendering. I am using VOLT to create the opentype rules. It is just a simple ligature substitution, without any complex mark re-ordering stuff.

Since, Brahmi is not yet supported in Windows, I have used Latin as the default script, and added the ligature substitution. Even while proof reading, the
substitution worked.

Volt_Screenshot_brahmi.jpg (133.69 KiB) Viewed 7242 times

But I installed the font, and checked it out. The ligature was not formed.

(U+11013, U+11038) [I am not able to post the actual SMP characters. The phpBB is throwing a sql error ]

KAA_Brahmi_Plane.jpg (46.08 KiB) Viewed 7242 times

Assuming SMP wouldn't be supported, I mapped the characters to Tamil. And assigned the script tag as Tamil in VOLT, and creating the opentype substitution rules. Even, then the ligature wouldn't form, even though proof reading windows in VOLT formed the ligature well.

கா(U+0B95, U+00BE)

Volt_Tamil.jpg (131.26 KiB) Viewed 7242 times

KAA_Tamil_Plane.jpg (51.82 KiB) Viewed 7242 times

Then, I proceeded to map the character to the Latin plan, with the script tag as Latin. And bingo the ligature got formed !

ka (U+0061, U+006B)

Volt_Latin.jpg (124.15 KiB) Viewed 7242 times

KAA_Latin_Plane.jpg (48.41 KiB) Viewed 7242 times

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When ligatures are getting formed with Latin code points, why is not getting formed for Tamil or Brahmi ?

Am I missing here something ?

I have attached the font files (with workign VOLT tables).

Brahmi_Brahmi_Sample.ttf

(3.48 KiB) Downloaded 374 times

Brahmi_Tamil_Sample.ttf

(3.51 KiB) Downloaded 339 times

Brahmi_Latin_Sample.ttf

(3.53 KiB) Downloaded 331 times

I would be very grateful to receive any guidance and support regarding this.

V

[Bhikkhu Pesala]

I was able to get the glyph substitutions to work for all three fonts using the Truetype Viewer to test them.

Tamil: \u0B95\u0BBE Latin: ka and Brahmi \00011013\00011038 all worked OK for me.

What does SMP mean? I am out of my depth when it comes to these higher Unicode planes.

Brahmi Ligatures.png (18.53 KiB) Viewed 7233 times

Brahmi Ligatures2.png (18.47 KiB) Viewed 7233 times

[virtualvinodh]

Bhante,

Can you please try rendering the characters in a word processor, and let me know if they render properly ?

V

[vanisaac]

Bikkhu, the SMP is the Supplementary Multilingual Plane. Every five digit code point starting with "1" is in the SMP, which is why it is also often called "plane 1". There is also a Supplementary Ideographic Plane (SIP) at plane 2, and a Supplementary Special-purpose Plane (SSP) at plane 14 (U+Exxxx). Planes 15 and 16 (U+Fxxxx and U+10xxxx) are the Private Use Planes. Soon, there will be a Tertiary Ideographic Plane (TIP) at plane 3. These all contrast with the Basic Multilingual Plane (BMP) at Plane 0 (U+0000..U+FFFF).

As for Vinodh's questions, I wish I had better news, but I have come to the conclusion that OpenType is probably not suitable for minority scripts. In Windows, so much of the functioning of OpenType features is dependent on Uniscribe and the assumptions contained therein that I wouldn't actually trust any of those features to consistently render until Brahmi is explicitly supported, which may be decades away. Obviously, Bikkhu has gotten some functionality, and I applaud both of you for your success in that realm. My suggestion to you moving forward is to explore Graphite, which works on the free (as in lunch) OpenOffice suite of text, spreadsheet, database, and presentation programs. The great thing is that with a bit of raw-text manipulation, and the smart use of spreadsheet columns, or a good background in the XML manipulation format XSLT, I think you can port Volt's VTP data to Graphite, which uses simple plain-text to encode its information.

[Bhikkhu Pesala]

Bhante,

Can you please try rendering the characters in a word processor, and let me know if they render properly ?

V

I don't have any Windows App that would render these fonts. PagePlus doesn't support these higher planes, and from what Vanisac says, LibreOffice doesn't support Uniscribe.

[jamadagni]

I don't have any Windows App that would render these fonts. PagePlus doesn't support these higher planes, and from what Vanisac says, LibreOffice doesn't support Uniscribe.

He only said Uniscribe supports Graphite. He didn't say it *didn't* use Uniscribe. It certainly supports OpenType (on Windows and elsewhere), but whether via Uniscribe or its own engine (ICU, I think) I'm not sure.

[vanisaac]

No. Uniscribe is the native windows OpenType feature engine, and it only recognizes and implements specific features for specific scripts and code points. It makes creating Arabic fonts really easy, because you don't have to program in all the logic of when you have initial/medial/final forms, you just have to indicate which glyphs are the given forms. Uniscribe contains all the information on when and where to do all of the substitutions and logic, but it also means that all but the most common scripts just plain aren't supported.

Graphite is an alternative to OpenType that has zero dependencies, because all of the feature logic is contained within the individual font. This means that a Graphite font can be for any script, including PUA assignments and brand-new Unicode allocations. The downside is that it is not natively supported in Windows, but is limited to certain programs. Fortunately, one of the programs is the entire suite of the OpenOffice text, spreadsheet, database, and slideshow programs. I think they might be natively supported by mozilla firefox as well, and the code is freely available, so a lot of the community-developed programs will properly render graphite fonts.