Re: [TCLCORE] Harfbuzz - text shaping

[Harald O. <har...@el...>]

Dear Kevin,

I can only encourage you in this action.
Unfortunately, we have no MS-Windows Tk Wizard in the community.
Ashok does not cover the GUI part.
So, little support out there.

But I will do what I can to support you.

Thanks for all,
Harald

Am 10.03.2026 um 20:22 schrieb Kevin Walzer:
> 
> It appears I can get a LOT of improvement from the following libraries 
> for text shaping and bidi:
> 
> Windows:
> 
> open-graph-image.png
> Uniscribe - Win32 apps <https://learn.microsoft.com/en-us/windows/win32/ 
> intl/uniscribe>
> learn.microsoft.com <https://learn.microsoft.com/en-us/windows/win32/ 
> intl/uniscribe>
> 
> <https://learn.microsoft.com/en-us/windows/win32/intl/uniscribe>
> 
> X11:
> 
> kb.png
> JimmyLefevre/kb: kb single-header C/C++ libraries <https://github.com/ 
> JimmyLefevre/kb>
> github.com <https://github.com/JimmyLefevre/kb>
> 
> <https://github.com/JimmyLefevre/kb>
> 
> SheenBidi.png
> Tehreer/SheenBidi: A sophisticated implementation of Unicode 
> Bidirectional Algorithm <https://github.com/Tehreer/SheenBidi>
> github.com <https://github.com/Tehreer/SheenBidi>
> 
> <https://github.com/Tehreer/SheenBidi>
> 
> Uniscribe is Microsoft’s older API for complex text shaping and bidi. 
> kb_text_shape.h is a much lighter single header library for text shaping 
> than harfbuzz, and SheenBidi can handle the bidi part; both are small 
> enough to bundle with Tk and have permissive licenses.
> 
> Because I want the Wayland port to have modern text display, I think it 
> makes sense to update Windows and, especially, X11 (since these two 
> libraries will also help power Wayland’s text display). I’m not even 
> anticipating any API changes here so I may just base this work on a bug 
> report and not ask for a TIP.
> 
> Thoughts?
> 
> —
> Kevin Walzer kw...@co...
> 
>> On Mar 10, 2026, at 9:35 AM, Harald Oehlmann 
>> <har...@el...> wrote:
>>
>> Hi Kevin,
>>
>> thanks for the great initiative.
>>
>> This ticket has some information of rendering issues on Windows:
>>
>> https://core.tcl-lang.org/tk/info/5d0bc3cfec7c1adb
>>
>> - no color glyphs
>> - no unification of composed flag unicode points.
>>
>> pack [text .t -blockcursor 1]
>> .t insert end "\U1F1E9\U1F1EA"
>>
>> Firefox does it right. I don't know how they do it.
>>
>> As a side note, this ticket needs a Tk wizard as sponsor. It is 
>> probably worthwile to be committed. Francois liked it...
>>
>> Thanks for all,
>> Harald
>>
>> Am 10.03.2026 um 13:51 schrieb Kevin Walzer:
>>> 
>>> Comparing Arabic displayed on Tk's text widget and Notepad on Windows 
>>> 11 - Tk produces the glyphs and preserves the RTL direction 
>>> correctly, as far as I can tell. But it looks like a sequence of 
>>> characters, not words - I think that is the difference that text 
>>> shaping has. Whatever Tk's text engine uses on Windows, it is not 
>>> very robust.
>>> macOS's Core Text API, whch Tk uses, has full support for RTL 
>>> languages and text shaping, and the differences in how Arabic is 
>>> rendered in Tk's text widget and Apple's TextEdit app are far less 
>>> pronounced - Tk does a good job here.
>>> On 3/10/26 7:49 AM, Kevin Walzer wrote:
>>>> It might make sense to it be an external dependency on Linux, of 
>>>> course. And perhaps the native rendering on Windows is good enough? 
>>>> Im not an expert there.
>>>> —
>>>> Kevin Wal...@co...
>>>>
>>>>> On Mar 10, 2026, at 7:33 AM, Kevin Walzer<kw...@co...> wrote:
>>>>>
>>>>> The other thing about Harfbuzz is that it’s cross-platform, MIT- 
>>>>> licensed, and possibly small enough to ship directly wirh Tk as a 
>>>>> support library. So we could incorporate it not just on Linux 
>>>>> (Wayland/X11) but Windows, where it could help modernize Tk’s 
>>>>> display of non-Western languages without requiring a full rewrite 
>>>>> of the GDI-based text API