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Font + window size (OSC 7777)

Category: extensions · Baseline: rich · Tags: Operating System Commands (OSC) · Specification ↗

ESC ] 7777 ; font ; size BEL
OSC 7777 sets both the font size and window size in a single zoom operation. The sequence is ESC ] 7777 ; font ; size BEL, where the font and size parameters control mintty's combined zoom behavior — adjusting the window dimensions to keep the visible character grid stable while the font changes. This is a mintty-specific zoom control that complements OSC 7770 (font size only). Like other mintty font extensions, it has no adoption outside mintty.
How this is testedpartial
Send OSC 7777 ; ; BEL (default zoom) and verify the terminal consumes the sequence (cursor position unchanged).

The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.

Analysis2026-04-06

Supported by all 4 tested terminals — universal adoption. Part of the Rich TUI baseline.

Supported by 8 of 14 backends (57%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
VS Code✓ yes
Warp✓ yes
Cursor✓ yes
Terminal.app✓ yes

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0? unknown
Kitty0.40.0? unknown
vt100.js0.2.1? unknown
vterm0.2.0? unknown
WezTerm0.1.0-fork.5? unknown
xterm.js5.5.0? unknown