How to check what is the minimum reshaping range when inserting a glyph?

RazrFalcon / rustybuzz

A complete harfbuzz's shaping algorithm port to Rust

MIT License

544 stars 34 forks source link

How to check what is the minimum reshaping range when inserting a glyph? #54

Closed wdanilo closed 2 years ago

wdanilo commented 2 years ago

Hi, I know that GlyphInfo::unsafe_to_break exists, but I think it does not cover my use case. I want to redraw only part of a long line of text after inserting a glyph. I want to know what part of the text should be redrawn. Let's consider the input அட0. If I insert ் after ட, then I should get ட் instead of ட, but I do not need to redraw neither அ nor 0. Is there any utility in Rustybuzz to discover it? If not, do you have any hints on how this can be done?

RazrFalcon commented 2 years ago

I never had such a task so no idea. And there is nothing rustybuzz to simplify this.

wdanilo commented 2 years ago

Gotcha! In such a case, I'm closing this topic here. Thanks for your help!

RazrFalcon commented 2 years ago

I would suggest asking in https://github.com/harfbuzz/harfbuzz directly and then adopting the solution to rustybuzz. After all, the API is mostly the same.

behdad commented 2 years ago

We have a newer glyph flag in HarfBuzz that can be used for this purpose, almost... It's called unsafe-to-concat. It's tricky to use though.

https://harfbuzz.github.io/harfbuzz-hb-buffer.html#HB-GLYPH-FLAG-UNSAFE-TO-CONCAT:CAPS