JetBrainsMono font renders taller (or shorter) on specific font sizes.

[virtuallyunknown]

Greetings, and thanks for developing ghostty!

I am interested in migrating from Gnome Terminal, and I noticed a really weird issue with the JetBrainsMono font. Under specific font-sizes, the font renders taller than it should. Here is an example:

On the left is Gnome Terminal, on the right is ghostty, both of which are set to have font-size of 11. If you take a closer look, you will immediately notice that the text on the right appears taller, almost as if it's stretched out vertically. I have tested other font sizes and 10, 12, 13, 14, 15 and 16 and they appear almost pixel perfect. Oddly enough, 22 also differentiates, but this time it's smaller than the original.

Here is a comparison graphic and a video I made to better demonstrate the differences. All the screenshots were taken after doing a full system reboot whenever I was changing the font-size value in ghostty config.

compare.mp4

At first I thought this might be an issue with the patched version of JetBrainsMono Nerd Font I was using, so I went ahead and downloaded the original unpatched version, but the problem was still there. Additionally, I tried adjusting adjust-cell-height as it was suggested to me, but that does not appear to have any effect on the font itself, just the height of the rows on which the text itself renders.

It goes without saying that this isn't some critical or breaking issue, and since ghostty just launched yesterday, there are probably more important things to take care of. Nevertheless, if someone knows what might be causing this and how to fix it, I would love to know.

Cheers!

---

Here is all the relevant configuration and information I could find. I tested in VM for this issue but was having the same problem on my desktop OS.

font-family=JetBrains Mono
font-style=Regular
font-size=22
# or 10/11/12/13/14/15/16

theme=catppuccin-macchiato

Ghostty 1.0.1-dev+0000000

Version
  - version: 1.0.1-dev+0000000
  - channel: tip
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.gtk
  - font engine: font.main.Backend.fontconfig_freetype
  - renderer   : renderer.OpenGL
  - libxev     : main.Backend.io_uring
  - GTK version:
    build      : 4.14.2
    runtime    : 4.14.2
  - libadwaita : enabled
    build      : 1.5.0
    runtime    : 1.5.0

> ghostty +list-fonts | grep JetBrains

JetBrains Mono
  JetBrains Mono Bold
  JetBrains Mono Bold Italic
  JetBrains Mono ExtraBold
  JetBrains Mono ExtraBold Italic
  JetBrains Mono ExtraLight
  JetBrains Mono ExtraLight Italic
  JetBrains Mono Italic
  JetBrains Mono Light
  JetBrains Mono Light Italic
  JetBrains Mono Medium
  JetBrains Mono Medium Italic
  JetBrains Mono Regular
  JetBrains Mono SemiBold
  JetBrains Mono SemiBold Italic
  JetBrains Mono Thin
  JetBrains Mono Thin Italic

> fc-list | grep JetBrains

/home/decho/.fonts/JetBrainsMono-SemiBoldItalic.ttf: JetBrains Mono,JetBrains Mono SemiBold:style=SemiBold Italic,Italic
/home/decho/.fonts/JetBrainsMono-ExtraBold.ttf: JetBrains Mono,JetBrains Mono ExtraBold:style=ExtraBold,Regular
/home/decho/.fonts/JetBrainsMono-ExtraLightItalic.ttf: JetBrains Mono,JetBrains Mono ExtraLight:style=ExtraLight Italic,Italic
/home/decho/.fonts/JetBrainsMono-Light.ttf: JetBrains Mono,JetBrains Mono Light:style=Light,Regular
/home/decho/.fonts/JetBrainsMono-Regular.ttf: JetBrains Mono:style=Regular
/home/decho/.fonts/JetBrainsMono-SemiBold.ttf: JetBrains Mono,JetBrains Mono SemiBold:style=SemiBold,Regular
/home/decho/.fonts/JetBrainsMono-Medium.ttf: JetBrains Mono,JetBrains Mono Medium:style=Medium,Regular
/home/decho/.fonts/JetBrainsMono-LightItalic.ttf: JetBrains Mono,JetBrains Mono Light:style=Light Italic,Italic
/home/decho/.fonts/JetBrainsMono-ExtraLight.ttf: JetBrains Mono,JetBrains Mono ExtraLight:style=ExtraLight,Regular
/home/decho/.fonts/JetBrainsMono-Italic.ttf: JetBrains Mono:style=Italic
/home/decho/.fonts/JetBrainsMono-Bold.ttf: JetBrains Mono:style=Bold
/home/decho/.fonts/JetBrainsMono-Thin.ttf: JetBrains Mono,JetBrains Mono Thin:style=Thin,Regular
/home/decho/.fonts/JetBrainsMono-BoldItalic.ttf: JetBrains Mono:style=Bold Italic
/home/decho/.fonts/JetBrainsMono-ExtraBoldItalic.ttf: JetBrains Mono,JetBrains Mono ExtraBold:style=ExtraBold Italic,Italic
/home/decho/.fonts/JetBrainsMono-ThinItalic.ttf: JetBrains Mono,JetBrains Mono Thin:style=Thin Italic,Italic
/home/decho/.fonts/JetBrainsMono-MediumItalic.ttf: JetBrains Mono,JetBrains Mono Medium:style=Medium Italic,Italic

System:
  Kernel: 6.8.0-49-generic arch: x86_64 bits: 64 compiler: gcc v: 13.2.0 clocksource: kvm-clock
  Desktop: Cinnamon v: 6.2.9 tk: GTK v: 3.24.41 wm: Muffin v: 6.2.0 vt: 7 dm: LightDM v: 1.30.0
    Distro: Linux Mint 22 Wilma base: Ubuntu 24.04 noble
Machine:
  Type: Kvm System: QEMU product: Standard PC (Q35 + ICH9, 2009) v: pc-q35-8.2
    serial: <superuser required> Chassis: type: 1 v: pc-q35-8.2 serial: <superuser required>
  Mobo: N/A model: N/A serial: N/A uuid: <superuser required> BIOS: SeaBIOS
    v: 1.16.3-debian-1.16.3-2 date: 04/01/2014
CPU:
  Info: 8x 1-core model: AMD Ryzen 9 7900 bits: 64 type: SMP smt: <unsupported> arch: Zen 4 rev: 2
    cache: L1: 8x 128 KiB (1024 KiB) L2: 8x 512 KiB (4 MiB) L3: 8x 16 MiB (128 MiB)
  Speed (MHz): avg: 3700 min/max: N/A cores: 1: 3700 2: 3700 3: 3700 4: 3700 5: 3700 6: 3700
    7: 3700 8: 3700 bogomips: 59199
  Flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
Graphics:
  Device-1: Red Hat QXL paravirtual graphic card driver: qxl v: kernel ports: active: Virtual-1
    empty: Virtual-2,Virtual-3,Virtual-4 bus-ID: 00:01.0 chip-ID: 1b36:0100 class-ID: 0300
  Display: x11 server: X.Org v: 21.1.11 with: Xwayland v: 23.2.6 driver: X: loaded: N/A
    unloaded: fbdev,modesetting,vesa dri: swrast gpu: qxl display-ID: :0 screens: 1
  Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 507x285mm (19.96x11.22") s-diag: 582mm (22.9")
  Monitor-1: Virtual-1 res: 1920x1080 hz: 75 size: N/A modes: max: 1024x768 min: 640x480
  API: EGL v: 1.5 platforms: device: 0 drv: swrast surfaceless: drv: swrast x11: drv: swrast
    inactive: gbm,wayland
  API: OpenGL v: 4.5 vendor: mesa v: 24.0.9-0ubuntu0.2 glx-v: 1.4 direct-render: yes
    renderer: llvmpipe (LLVM 17.0.6 256 bits) device-ID: ffffffff:ffffffff
Audio:
  Device-1: Intel 82801I HD Audio vendor: Red Hat QEMU Virtual Machine driver: snd_hda_intel
    v: kernel bus-ID: 00:1b.0 chip-ID: 8086:293e class-ID: 0403
  API: ALSA v: k6.8.0-49-generic status: kernel-api
  Server-1: PipeWire v: 1.0.5 status: active with: 1: pipewire-pulse status: active
    2: wireplumber status: active 3: pipewire-alsa type: plugin
Network:
  Device-1: Red Hat Virtio 1.0 network driver: virtio-pci v: 1 pcie: speed: 2.5 GT/s lanes: 1
    port: N/A bus-ID: 01:00.0 chip-ID: 1af4:1041 class-ID: 0200
  IF-ID-1: enp1s0 state: up speed: -1 duplex: unknown mac: <filter>
Drives:
  Local Storage: total: 30 GiB used: 18.92 GiB (63.1%)
  ID-1: /dev/vda model: N/A size: 30 GiB speed: <unknown> tech: N/A serial: N/A scheme: GPT
Partition:
  ID-1: / size: 28.87 GiB used: 18.91 GiB (65.5%) fs: ext4 dev: /dev/vda3
  ID-2: /boot/efi size: 512 MiB used: 6.1 MiB (1.2%) fs: vfat dev: /dev/vda2
Swap:
  ID-1: swap-1 type: file size: 2 GiB used: 0 KiB (0.0%) priority: -2 file: /swapfile
USB:
  Hub-1: 1-0:1 info: hi-speed hub with single TT ports: 15 rev: 2.0 speed: 480 Mb/s lanes: 1
    chip-ID: 1d6b:0002 class-ID: 0900
  Device-1: 1-1:2 info: Adomax QEMU Tablet type: HID driver: hid-generic,usbhid interfaces: 1
    rev: 2.0 speed: 480 Mb/s lanes: 1 power: 100mA chip-ID: 0627:0001 class-ID: 0300 serial: <filter>
  Hub-2: 2-0:1 info: super-speed hub ports: 15 rev: 3.0 speed: 5 Gb/s lanes: 1 chip-ID: 1d6b:0003
    class-ID: 0900
Sensors:
  Src: lm-sensors+/sys Message: No sensor data found using /sys/class/hwmon or lm-sensors.
Repos:
  Packages: 2468 pm: dpkg pkgs: 2457 pm: flatpak pkgs: 11
  No active apt repos in: /etc/apt/sources.list
  Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list
    1: deb http: //packages.linuxmint.com wilma main upstream import backport
    2: deb http: //archive.ubuntu.com/ubuntu noble main restricted universe multiverse
    3: deb http: //archive.ubuntu.com/ubuntu noble-updates main restricted universe multiverse
    4: deb http: //archive.ubuntu.com/ubuntu noble-backports main restricted universe multiverse
    5: deb http: //security.ubuntu.com/ubuntu/ noble-security main restricted universe multiverse
  Active apt repos in: /etc/apt/sources.list.d/vscode.list
    1: deb [arch=amd64,arm64,armhf] https: //packages.microsoft.com/repos/code stable main
Info:
  Memory: total: 8 GiB available: 7.66 GiB used: 1.4 GiB (18.2%)
  Processes: 345 Power: uptime: 1m states: freeze,mem,disk suspend: s2idle wakeups: 0
    hibernate: shutdown Init: systemd v: 255 target: graphical (5) default: graphical
  Compilers: gcc: 13.2.0 Client: Cinnamon v: 6.2.9 inxi: 3.3.34

[mitchellh]

Convert to discussion for issue triage.

[qwerasd205]

This is due to gnome-terminal not forcing the autohinter, it should be identical with freetype-load-flags = no-force-autohint.

[virtuallyunknown]

Thanks a lot for this, it didn't occur to me to change this settings, didn't even think it could be related but I want to confirm for anyone possibly reading this discussion later on that this fixes the problem.

[qgates]

Not sure if it's related but I've noticed that fonts render fractionally less tall at 14pt than Wezterm and Gnome-terminal. Using JetBrainsMono, cell width and cell/line height are the same, but the text is slightly squashed.

With a block cursor, the cursor size is the same as other terminals, but there is a little more padding at the top. It's most visible on letter 'F' (both cases).

Arch, Cinnamon desktop