[RFC] OpenType Variable font support and new UI for choosing fonts

[kovidgoyal]

Hi all,

I have added support to kitty for OpenType variable fonts. This means that, for fonts that support it, you can precisely control the weight, spacing, italic angle, etc. There is also a new UI in the form of the choose-fonts kitten to make selecting fonts and setting their features and variable values easier. Run it with:

kitten choose-fonts

See the docs for the this kitten

Some screenshots of the kitten:

The code works on both Linux and macOS. Note that this required extensive re-writing of font selection internals so there could be regressions.

I would appreciate some testing from those of you in a position to do so, as there are two platforms and dozens of fonts and settings and thousands of lines of code involved, it's hard for me to cover everything.

You can use the kitty nightly build or build kitty from source.

Note that the existing font_features setting in kitty.conf still works, but is obsoleted by the new choose fonts kitten. It should only be used for fallback fonts. The main fonts should have their features configured via choose-fonts.

Thanks, and enjoy.

[neurocyte]

I have an issue building on Arch Linux:

> ./dev.sh build
[32/32] Compiling kitty/window_logo.c ... done
Compiling kitty/keys.c ...
gcc -MMD -DNDEBUG -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include -Wextra -Wfloat-conversion -Wno-missing-field-initializers -Wall -Wstrict-prototypes -std=c11 -pedantic-errors -Werror -O3 -fwrapv -fstack-protector-strong -pipe -fvisibility=hidden -fno-plt -fPIC -D_FORTIFY_SOURCE=2 -flto -fcf-protection=full -march=native -mtune=native -pthread -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/libpng16 -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/freetype2 -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/libpng16 -I/usr/include/uuid -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/harfbuzz -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/freetype2 -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/libpng16 -I/home/cjv/pkgs/kitty/dependencies/linux-amd64/include/python3.11 -c kitty/keys.c -o build/fast_data_types-kitty-keys.c.o
kitty/keys.c: In function ‘is_no_action_key’:
kitty/keys.c:55:14: error: ‘XKB_KEY_XF86Fn’ undeclared (first use in this function); did you mean ‘XKB_KEY_XF86Go’?
   55 |         case XKB_KEY_XF86Fn:
      |              ^~~~~~~~~~~~~~
      |              XKB_KEY_XF86Go
kitty/keys.c:55:14: note: each undeclared identifier is reported only once for each function it appears in
The following build command failed: /home/cjv/pkgs/kitty/dependencies/linux-amd64/bin/python setup.py develop
exit status 1

[neurocyte]

I have an issue building on Arch Linux

Nevermind. My bad. ./dev.sh deps fixed it.

[neurocyte]

After pressing enter on the initial font selection screen I get this:

$ kitten choose-fonts
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/home/cjv/pkgs/kitty/__main__.py", line 7, in <module>
    main()
  File "/home/cjv/pkgs/kitty/kitty/entry_points.py", line 192, in main
    namespaced(['+', first_arg[1:]] + sys.argv[2:])
  File "/home/cjv/pkgs/kitty/kitty/entry_points.py", line 146, in namespaced
    func(args[1:])
  File "/home/cjv/pkgs/kitty/kitty/entry_points.py", line 24, in runpy
    exec(args[1])
  File "<string>", line 1, in <module>
  File "/home/cjv/pkgs/kitty/kittens/choose_fonts/backend.py", line 217, in main
    opts, family_key, dpi_x, dpi_y = opts_from_cmd(cmd)
                                     ^^^^^^^^^^^^^^^^^^
  File "/home/cjv/pkgs/kitty/kittens/choose_fonts/backend.py", line 75, in opts_from_cmd
    opts.foreground = to_color(ts['foreground'])
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/cjv/pkgs/kitty/kitty/conf/utils.py", line 60, in to_color
    ans = as_color(x, validate=True)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/cjv/pkgs/kitty/kitty/rgb.py", line 73, in to_color
    raise ValueError(f'Invalid color name: {raw}')
ValueError: Invalid color name: 
Error: exit status 1

[kovidgoyal]

Are you running kitten choose-fonts inside an instance of kitty built from source as well?

[neurocyte]

You are right. I was somehow getting my kitty versions mixed up. I deinstalled the arch version of kitty and restarted all my kitty sessions and now it works.

[JorgeVV]

I get segfault when trying to select any Monaspace's font from the list. kittly nightly build

$ kitten choose-fonts
Error: signal: segmentation fault

[kovidgoyal]

Works for me with both Monaspace Argon Var and Monaspace Neon. Post the actual backtrace. What OS are you running on? And exactly what steps dd you take leading to the segfault.

[JorgeVV]

What OS are you running on?

MacOS 12.7.1.

Post the actual backtrace

The only output I get is Error: signal: segmentation fault. Is there a log file with more details?

And exactly what steps dd you take leading to the segfault

I just installed the nightly build. Previously I was on latest stable.

1. run kitten choose-fonts
2. Kitten loads. I can see a list of font families.
3. I change current selection with arrows keys ↑ ↓
4. If I select any of Monaspace's (just selecting it in the font list, not choosing it by pressing enter), the process exits and I get the output mentioned above.

[trygveaa]

There is something going on with ligatures in the font preview, parts of them are invisible. You can see in the first screenshot below that part of the <=> and |} ligatures are missing.

Preview of JetBrains Mono, looks wrong:

Preview of JetBrains Mono NL (same font without ligatures), looks correct:

The same characters printed normally in the terminal with JetBrains Mono (with ligatures), looks correct:

The font is installed from the ttf-jetbrains-mono package in Arch Linux, version 2.304-1. Running kitty commit 190048080.

[kovidgoyal]

On Mon, Jun 24, 2024 at 09:09:07AM -0700, Jorge Villalobos wrote:

What OS are you running on?

MacOS 12.7.1.

Post the actual backtrace

The only output I get is Error: signal: segmentation fault. Is there a log file with more details?

There should be a crash report available via Console.app

And exactly what steps dd you take leading to the segfault

I just installed the nightly build. Previously I was on latest stable.

1. run kitten choose-fonts
2. Kitten loads. I can see a list of font families.
3. I change current selection with arrows keys ↑ ↓
4. If I move into any of Monaspace's (just selecting it in the left list, not choosing it pressing enter), the process exits and I get the output mentioned above.

Doesnt repro for me on macOS, however, I can only get the Monaspace Var fonts to show up not the non variable ones. Are you using up to date monaspace fonts and where exactly did you get them from?

[kovidgoyal]

On Mon, Jun 24, 2024 at 09:24:38AM -0700, Trygve Aaberge wrote:

There is something going on with ligatures in the font preview, parts of them are invisible. You can see in the first screenshot below that part of the <=> and |} ligatures are missing.

https://github.com/kovidgoyal/kitty/commit/a8daf067377c8a5214d7bb246288280cbeb8161c

[trygveaa]

a8daf06

Thanks, works now.

[JorgeVV]

There should be a crash report available via Console.app

Crash report

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Bytes after previous region: 1 Bytes before following region: 1257472 REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL mapped file 10b0e1000-10b14f000 [ 440K] r--/rw- SM=COW ...t_id=cf74c2a7 ---> GAP OF 0x133000 BYTES __TEXT 10b282000-10b6be000 [ 4336K] r-x/rwx SM=COW ...s/3.12/Python Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 libsystem_platform.dylib 0x7ff802f49189 _platform_memmove$VARIANT$Haswell + 41 1 Python 0x10b316b81 PyBytes_FromStringAndSize + 225 2 Python 0x10b4f9e8e va_build_stack + 158 3 Python 0x10b327a4e _PyObject_CallFunctionVa + 94 4 Python 0x10b328074 _PyObject_CallFunction_SizeT + 164 5 Python 0x10b3e03c0 unicode_decode_call_errorhandler_writer + 224 6 Python 0x10b3dd764 unicode_decode_utf8 + 2468 7 Python 0x10b4f8a51 do_mkvalue + 1121 8 Python 0x10b4f9c60 _Py_BuildValue_SizeT + 208 9 kitty.fast_data_types.so 0x10ca351f6 0x10ca1e000 + 94710 10 Python 0x10b47a08a _PyEval_EvalFrameDefault + 72842 11 Python 0x10b46738b PyEval_EvalCode + 299 12 Python 0x10b512533 run_mod + 147 13 Python 0x10b5157bc PyRun_StringFlags + 108 14 Python 0x10b4629fa builtin_exec + 698 15 Python 0x10b391d7b cfunction_vectorcall_FASTCALL_KEYWORDS + 75 16 Python 0x10b477a4c _PyEval_EvalFrameDefault + 63052 17 Python 0x10b46738b PyEval_EvalCode + 299 18 Python 0x10b4628fd builtin_exec + 445 19 Python 0x10b391d7b cfunction_vectorcall_FASTCALL_KEYWORDS + 75 20 Python 0x10b477a4c _PyEval_EvalFrameDefault + 63052 21 Python 0x10b53f5bc pymain_run_module + 268 22 Python 0x10b53ee68 pymain_run_python + 1192 23 Python 0x10b53e977 Py_RunMain + 23 24 kitty 0x10a209849 0x10a203000 + 26697 25 kitty 0x10a20894b main + 2411 26 dyld 0x119c2352e start + 462 Thread 1: 0 libsystem_pthread.dylib 0x7ff802f31f48 start_wqthread + 0 Thread 0 crashed with X86 Thread State (64-bit): rax: 0x00007f9ea0700020 rbx: 0x0000000100000004 rcx: 0x00000000fffacb00 rdx: 0x0000000100000004 rdi: 0x00007f9ea0753524 rsi: 0x000000010b14f000 rbp: 0x00007ff7b5cf9ad0 rsp: 0x00007ff7b5cf9ad0 r8: 0x0000000000000000 r9: 0x0000000000000003 r10: 0x0000000000000003 r11: 0x00007f9d95604524 r12: 0x0000000000000001 r13: 0x00007ff7b5cf9b30 r14: 0x00007f9ea0700000 r15: 0x000000010b0fbafc rip: 0x00007ff802f49189 rfl: 0x0000000000010202 cr2: 0x000000010b14f000 Logical CPU: 4 Error Code: 0x00000004 (no mapping for user data read) Trap Number: 14 Thread 0 instruction stream: c1 48 83 c1 10 3d ff ff-00 00 74 db f7 d0 0f bc .H...=....t..... c0 48 01 c1 48 0f b6 44-0f f0 4c 0f b6 44 0e f0 .H..H..D..L..D.. 4c 29 c0 5d c3 90 90 90-90 90 90 90 90 90 90 90 L).]............ 90 90 90 90 90 90 90 55-48 89 e5 49 89 fb 49 29 .......UH..I..I) f3 48 89 f8 49 39 d3 72-1b 48 83 fa 60 76 2f 48 .H..I9.r.H..`v/H 81 fa 00 40 00 00 0f 82-cb 00 00 00 48 89 d1 fc ...@........H... 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Doesnt repro for me on macOS, however, I can only get the Monaspace Var fonts to show up not the non variable ones.

Likewise, only var fonts show up.

Are you using up to date monaspace fonts and where exactly did you get them from?

Yes V1.101. Followed install instructions as specified at monaspace's README.md

$ git clone https://github.com/githubnext/monaspace.git
$ cd monaspace
$ ./util/install_macos.sh

[kovidgoyal]

Hmm, that backtrace has no kitty code in it. Could indicate memory corruption. Can you build kitty with sanitizers as described here: https://sw.kovidgoyal.net/kitty/build/#building-in-debug-mode

might give a more useful backtrace.

Also does the crash happen if you run

kitty --config=NONE kitten choose-fonts

and try to select the monaspace fonts.