Stylistic sets have problem with using dSignI

[mehulchanpura]

Stylistic Set glyph named dKTa.ss02 is typing perfectly in MS Word, but if i add dSighI (Matraa) then this time this dSignI matra is following base glyph dKTa's logic, and it's displaying dSignI.W (Matraa). And it is not looking good for dKTa.ss02 because this glyph have different width, and even if i add dAnusvara it's look like there is big problem in this point. I am trying to share a screenshot of how both stylistic Sets are looking after dSignI or and with dAnusvara.

Please provide me a solution for it. I am just a beginner and trying to how can i use different Stylistic Sets and modify font as my requirement. I try to use ChatGpt for 6 days but finally i think only this font developer can give me a correct answer or guide me to which correct path i can solve this problem.

As long as i think using dKTa.ss02 with dSignI will be not dSignI.W but default dSignI or may dSignI.M (Matraa).

I hope somebody can guide me for solution of this problem.

[tiroj]

Thank you for reporting this. This is a confirmed bug, which I suspect is due to the ordering of the lookups for the stylistic set feature relative to the lookup that selects the width of ikar to apply. This will need to be fixed in the font, as there is no easy work-around in text processing software.

I will prioritise fixing this.

[tiroj]

This has been fixed in Tiro Devanagari Hindi and Tiro Devanagari Marathi.

The updated fonts (v1.62) are available in the /fonts folder, and have also from
https://www.tiro.com/fonts/tiro-devanagari-hindi
https://www.tiro.com/fonts/tiro-devanagari-marathi

It will probably be some time before they are picked up by Google Fonts, though.

[mehulchanpura]

Thank you very much tiroj for providing me dev version 1.62 of this font.

I am not a font creator, I am just trying to modify existing font as per my requirement. I am very new in this field so as long as I am working I have some basic types questions like, if I create Substitute of any glyph, suppose if I create a substitute glyph like dTtPa.ss02 for dTtPa for to replace it when i will typing, now with your dev font file I can easily work on this, but recently I notice and confused that dUdatta with dTtPa is placed above on last like dPa.

I will modify font in different names so I can share a screenshot of typed text where I get confused that which one is correct.

Honestly I don't know if this is a right platform to ask (know) how this things should be works.

I am sharing screenshot of four different types of combinations. First one is as default, and then next are different types of substitutes with Udatta plus dSignI.

I am really very sorry if i ask my confusion here in this platform, but I want to learn and contribute how can I or we can modify native font as per our requirements.

It will be pleasure for me if I get knowledge how dUdatta must need it's position if we create a substitute of any glyph in devanagari, I just want to make sure that is dUdatta is strictly followed by his native character or we can use or put it on the last character of the combination?

I am sorry again if I ask this question in this platform and heartily sorry if I waste developers' time.

Now here is the screenshot which I mentioned. Please guide me.

[tiroj]

My understanding is that the udatta mark is normally input at the end of a conjunct (and following a vowel sign if present). As is typically the case with stress accent marking, the sign applies to the produnciation of the consonant+vowel[+consonant] syllable, hence it always comes at the end of the cluster. This is an expectation of Unicode text processing, and an udatta input before a vowel sign will be flagged as an invalid sequence by shaping engines:

So I build my fonts with that assumption, and include contextual positioning rules to move the udatta slightly right and/or up to clear the vowel sign, as you see here

[This is Tiro Devanagari Hindi, in the Sanskrit fonts the mark is positioned differently, above vowel marks, presuming Vedic accentuation.]

I am not quite sure how you are inputting the sequences that result in these shapings, but neither looks right:

Devanagari shaping engines follow a modern Hindi rule in which the ikar will not reorder past an explicit halant, so the if I user ZWNJ (U+200C) to force the presence of an explicit halant, what I will get is

(with the udatta still input at the end of the cluster, after the vowel sign).

[mehulchanpura]

Thank you very much tiroj for you detailed answer.

I think I may made my question much complicated and without add details how I did input sequences. My English is not that good but I am still trying to understand and asking my question in English, so I can get solution of my doubts.

Let me re explain my question again, your font already have dTtPa glyph, but while I am working on transcription or using OCR for to convert and type those devanagari texts in unicode, many times I need to type dTta+zero widhth non joiner+dPa, so I thought what if I will modify font and create a substitute of dTtPa as dTtPa.ss02, and I made this and looks like this in my modified font.

Then I thought what if this dTtPa.ss02 have with dSignI matra (i mean like dTtPa.ss02+dSignI), so after creating dTtPa.ss02 I add this glyph in 'pres' Pre Base Substitutions in Devanagari2 lookup 11 contextual 2, and after that if I type dTtPa.ss02+dSignI, it's look like this,

Then when I am checking positioning of Anchor points, I notice there is a anchor for dUdatta, and here I get confused, that where should I need to position dUdatta in this case, at the top of the last on Pa, and that's why I positioned dUdatta like this,

If I will not create dTtPa.ss02 visually like above screenshot, in that case I need to to type dTta+dHalant+zero width non joiner+dPa+dSignI+dUdatta, and in this sequence it will be visually look like this,

In this case I can type this sequence without modify your font, but there are some other glyph I must need to create a substitute for them to visually look same like my pdf while I am typing in MS Word. Normally I still didn't need requirements to type like dTta+dHalant+zero width non joiner+dPa+dSignI+dUdatta, but there is question in my mind what if I will need this sequences in future! and that's why I am confused.

After reading your reply, I am not that good in English to understand, but as long as I understand and then one more question rise in my mind is that not possible this type of sequence in modern devanagari, like dTta+dSignI+dHalant with or without following dPa or any other devanagari character? is it really not ideal to type dTta+dSignI+dHalant, I mean this not possible in modern Devanagari?

It's true that I am asking because lack of my knowledge about how to write Devanagari/Hindi language. In Unicode font there are anchors in glyph and those all anchors are following their assigned sign, so I got confused what if these signs will I need to use with any of the substitute glyph added by me in my modified font or with combination using zero width non joiner or in future what if I will need to use any of these anchors assigned sign with my modified .ss02 substitutes. This is my concern and I have no mentor, I am just trying to learning on base of trial & error.

I know without mentor or without any faculty guidance it's almost impossible to understand whole concept, but still I am trying and thank you very much for your detailed and kind reply.

[tiroj]

Then when I am checking positioning of Anchor points, I notice there is a anchor for dUdatta, and here I get confused, that where should I need to position dUdatta in this case, at the top of the last on Pa, and that's why I positioned dUdatta like this,

My understanding is that this is correct if one is displaying the conjunct sequence with explicit halant.

Regarding ordering, the standard order for Devanagari clusters following the Unicode model adapted from ISCII, is

Consonant [nukta] [halant] [Consonant] ... | Vowel Sign | Accent

This is a kind of phonetic ordering, following the order in which the characters are pronounced rather than the order in which they are written. Some sequences that do not follow this standard order may be marked as invalid by a shaping engine, e.g. applying a vowel sign directly following a halant, but some others may be permitted because of odditites in some orthographies. So the sequence you describe in which the halant follows the ikar can be cleanly rendered टि्प but this is problematic because it reads the same way as ट्पि, but now there is confusion about how the sequence is encoded. I recommend following standard encoding order practice.

[mehulchanpura]

Thank you so much tiroj.

As long as I understand your explanation, it is not ideal to write टि्प (dTta+dSignI+dHalant+zero width non joiner+dPa), like this in bellow screenshot

we should may write ट्‌पि (dTta+dHalant+zero width non joiner+dPa+dSignI) like this in bellow screenshot

in this case I assume that I may understand your this point.

For now if we just forget about dUdatta and only focus on above writing style.

I am still confused that what if i use your font and type ट्पि (dTtPa+dSignI) !, in this particular case, is this correct/ideal as modern writing style in Devanagari? Chrome may not support your actual font so I am sharing screenshot bellow so we can understand it clearly,

I typed this in your TiroDevanagariHindi 1.62 font, is this above writing style is ideal as modern Devanagari?

I am asking because I just want to substitute of dTtPa to dTtPa.ss02 in my modified font and this dTtpa.ss02 will look like this as bellow screenshot.

It is a single glyph, it is visually looks like two different character, but cursor in MS Word can not behave like these are two different characters. Is It look correct/ideal as modern Devanagari?

I am asking because my intention for to create dTtPa.ss02 is, in my transcription work I am working on Jain Digambar Shastra, and there are many words which need to visually look like my above screenshot (visually need dHalant between two characters), so I just want to create substitutes for all those glyphs in your 1.62 version font.

I am not quite sure that I will also may need to add dSignI or dUdatta for these substitutes or not for now, but for now I just want to be clear/sure that replacing dTtPa to dTtPa.ss02 as I shown in above screen shot is correct or not?

And if typing this (dTtPa+dSignI) in your 1.62 version font is correct/ideal which like bellow screenshot

so if above sequence is correct/ideal, then what your opinion about if I type dTtpa.ss02+dSignI in my modified font? I am sharing screenshot bellow, because it is just a substitute glyph and behave like one single glyph/character in MS Word, I just modify your font, so it will be easy to understand both of us.

I am stuck here at this point and I don't understand how it is that important if I create a substitute for dTtPa to dTtPa.ss02, it's just visually look different but Unicode is still behave like this is just a one character of two character's combination, there will be no two separate characters as Unicode if I use my above dTtPa.ss02.

I like your font very! very! very! much, because I was just finding font like this which characters are visually similar like native Devanagari/Hindi writing style on paper with pencil. There are many different shaped fonts but those are much complicated for modify, and your font is visually almost look nice and also have not that complex logical need to modify it.

This 1.62 font still have some problems that I noticed, and I want to share those problem here with you, but for now in my modifying process I feel that first I need to solve my this doubt about this substitute of dTtPa to dTtPa.ss02.

Once your concept about this will be clear in my mind, very first I will make all those substitute glyphs, and then my second stage will be on other issue in this font.

I heartily appreciate your every reply even if I don't understand English that much, but still we are working and I hope we will be continue working on this.

I am asking this much long-long and it's may sounds like I am selfish and asking solution just because I want a solution of my doubts and you are the only one source I found that is reliable, but it's not 100% true, I like your font very much and want this font will be much better and better and have options for users like me.

Again thank you so much tiroj. I understand it may make you feel tired to explain concept repeatedly every time which you understand about knowledge of Devanagari in your life to me.

All I can say is THANK YOU SO MUCH for creating this font and replying me. Gratitude... Gratitude...

[tiroj]

This is the traditional form of the TtPi conjunct, which we favour in our fonts because it is possible to use ZWNJ to prevent the ligature, but not vice versa, i.e. there is no way to override an explicit halant using a formatting control character. So we make the traditional form the default. Also, the Tiro Indic fonts developed out of the typefaces we made for the Murty Classical Library of India, so the traditional forms were preferred.

If you use ZWNJ to force an explicit halant, then you are going to get this form

because the shaping engine that looks after the ordering of the glyphs follows modern Hindi conventions and does not reorder an ikar past an explicit halant (in the other direction, it will also not reorder a repha past an explicit halant.

There is a way to build a font such that the default display of TtPi is what you want, but it means changing the default behaviour. It sounds like this might be what you want, given your transcription needs: a custom version of the Tiro font with modified layout tables that displays TtPa — and perhaps some other conjuncts? — using a nominal half form substitution, i.e. Tt with a halant as a combined glyph instead of having an actual halant glyph in the text run.

The Tiro Devanagari Hindi source actually contains the glyphs you would need for this — I included them in anticipation of this kind of request —, but they are not currently used. So there is a glyph in the font called /dTth.half, and similar glyphs for other letters that do not take actual half forms:

So it would be possible to fork the font under some new name, and edit the OpenType Layout tables to change the way the conjuncts involving these letters are processed. This would involve

1. Adding these to the half form substitition lookup
2. Removing the traditional ligatures in the cjct substitution lookup
3. Adding these half forms to the relevant half form groups used in ikar width selection etc.

I think that is probably all that one would need to achieve your desired presentation.

[mehulchanpura]

Thank you so much tiroj.

I may not understand your last part where you mention this **'So it would be possible to fork the font under some new name, and edit the OpenType Layout tables to change the way the conjuncts involving these letters are processed. This would involve

Adding these to the half form substitition lookup
Removing the traditional ligatures in the cjct substitution lookup
Adding these half forms to the relevant half form groups used in ikar width selection etc.'**

But I understand and I feel that it will be not a good idea to create substitute of any glyph which substitute need to visually look Halant between two characters. Because in future if I will need to add dSignI with that newly created .ss02 glyph, it will may not visually look ideal, so I am thinking not to create substitute glyphs for those character combinations which may need Halant between them.

Even if I use zero width non joiner for it, and it will be visually look ideal if I will need to add dSignI after last character.

What I understand for now is this.

So I feel that it's better to use zero width non joiner instead of creating new substitutes for those glyphs.

Now I have new doubt about to create substitute glyph which may doesn't need Halant between combination of those two characters.

There are some glyps for example like dKNa, I created a substitute glph for this named dKNa.ss02, because my pdf visually look different for combination of this both characters, here I am sharing screenshot of both, first one is your original font combination and second one is my created dKNa/ss02 glyph, so you can visually understand what I want for my document.

There I also add dSignI in screenshot, because I already modify dSignI default to wide for this substitute in font lookup.

Is this correct to create substitute of this types of glyps which doesn't need Halant between those?

If you want I will generate a new issue for this or if it is okay for you, we can continue here.

Again thank you so so much tiroj, because you guide me how Halant between two characters need attention.

Thank you for your kind guidance.

[tiroj]

But I understand and I feel that it will be not a good idea to create substitute of any glyph which substitute need to visually look Halant between two characters. Because in future if I will need to add dSignI with that newly created .ss02 glyph, it will may not visually look ideal, so I am thinking not to create substitute glyphs for those character combinations which may need Halant between them.

To clarify, my proposed approach does not require creating .ss02 or other new glyphs. Rather, it changes the behaviour of the retroflex consonants and others that take a visible halant in horizontal conjuncts to act as if they were half forms. The ikar width selection in this case is triggered by the same contextual lookups that apply to half form sequences.

Regarding the second part of your message: for many combinations not involving visible halant, you can trigger a horizontal layout like this by using ZWJ U+200D after the halant character. This triggers the half form of the first consonant, and overrides the traditional ligature form. So, for example, this form

can be rendered with dKa dHalant ZWJ dNa dSigni क्‍नि

[mehulchanpura]

Thank you so much tiroj for to remind me that I can use ZWJ also, but if I will use in this 1.62 version dSignI maatra will be implied same as dSignI, instead of if combination of two or three character will should be implied or replace dSignI to dSignI.W.

This is the first part of my reply/message.

I am using chrome browser and in your reply I can see that dKa+dHalant+ZWJ+dNa+dSignI is still looks perfect, maybe because chrome use different font, I am just sharing screenshot of your reply first, and then I well share other screenshot of text table which I created to explain what is the problem if I use ZWJ instead of creating new substitute.

First I want to share a screenshot of your last line of your reply which contains 'क्‍नि', it's looks perfect in chrome browser, but in document editor like MS Word or any other if I type this dKa+dHalant+ZWJ+dNa+dSignI, it look different, so please first check this screenshot of our conversation here in chrome browser.

In your reply while you type 'क्‍नि' in this chrome browser, it's look okay because may chrome's font use correct width of i maatra for this combination.

But in our case, if we use this combination dKa+dHalant+ZWJ+dNa+dSignI, this will not replace dSignI to dSignI.W.

I prepare one text table so we can understand it better, and I am sharing screenshot of that text table bellow.

As I told I don't have idea how to manipulate logics, like if we use ZWJ. And I already created few substitutes for this types of character combinations (glyps).

So in first column I just type as you suggest me like 'dKa+dHalant+ZWJ+dNa+dSignI' and in second column shows the combination of substitutes which I created in my modified font. In second column I just type 'dKNa.ss02+dSignI', 'dGNa.ss02+dSignI', 'dGhNa.ss02+dSignI'.

I already add these types of few substitute glyphs which I created as per my requirement in 'lookup 11 contextual 2', so when I type above substitutes with dSignI, it will visually display like above screenshot. I mean with my created substitutes with dSignI will be replace dSignI to dSignI.W, and as I feel it look better then we can use 'dKa+dHalant+ZWJ+dNa+dSignI'.

My understanding about font logic like how and which logics need to create GSUB & GPOS is very limited, but I create substitute for those, just because I think this will be better instead of using ZWJ, because i maatra is not changing in this native font and as per my expectation it should be like dSignI to dSignI.W if glyph length is changed to wide. Maybe there is a solution for this also available in our native 1.62 font! if there is please guide me.

So for nor now I have this doubt, and I want to ask you is this correct if I need these types of substitutes in my transcription text which also need dSignI.W ?

This bellow is the second part of my reply.

There is lot of work I need to do with your font if I want to modify as per my requirement, and also there is some core concern I noticed and I am very hopeful that we can solve this. I mean you and your team can solve this. I canl just give you feedback or ask my doubts about this font, rest is totally depend on your and your team.

Me and rest of all other users are depending on you only.

tiroj thank you very very much again. I hope this font will be the best and simplest Devanagari Unicode font in word.

I appreciate you and your team's hard work to build this font.

This is the third part of my reply/message.

For now I am focusing on how can I modify this font as per my requirement, but I want to go step by step, I have other concern also about this font, but later we will can discuss on that. Because if I start sharing all of those my feedbacks about this font to you, it will maybe to complicated for me to understand your concept about this font logic.

So for now I am sharing or asking my doubts which are related to my desired font, but I promise I will feedback you all those things which I noticed, for example dChandrabindu is not positioned visually look nice in some cases, but for now I am avoiding this, because I can not learn or understand everything all at a time.

So please don't think like I want only about my desired modified font. I will be here and after solving this issue, if you want, we will be generate a new issue whenever you feel to do this.

Since that, again thank you so much.

My English is poor so I want to tell you in Hindi, धन्यवाद! मैं कृतज्ञ हूँ कि मुझे आपसे मदद मिल रही है।

🙏🙏

[tiroj]

The context statement in the lookup that substitutes the widest ikar variant glyph can contain sequences of glyphs or groups of glyphs, not just individual glyphs. So I think it should be possible to automatically trigger this substitution when a half form sequence has been triggered by ZWJ. In fact, this is probably what should be happening by default in these Devanagari fonts.

At present, the context statemement in the lookup dxxx.pres_ikar\W is

| <x.ikarW>

we can add a second statement, so the context is

| <x.ikarW>
| <d.half_forms>

That will susbtitute the wider ikar before any half form sequence (the <d.half_forms> group already exists. I think this will be appropriate, but needs to be tested with the narrowest half forms followed by the narrowest full forms to make sure the ikar is not too wide.

It is, of course, possible to add variant conjunct ligatures as you propose, but it may not be necessary to achieve the results you want. A lot of the decisions depend on how you want to work with the font in your document process.

---

Regarding the chandrabindu positioning (and also the anusvara positioning): this is based on our review of manuscript practice and what was done in the best metal types. A lot of technologies, from typwriters to digital fonts, have positioned these mark always above the final stem of the base letter, but that is not the traditional scribal practice.