Popup-menu feasibility study¶

Every entry from xterm patch-411's mainMenu (Ctrl-Button1), vtMenu (Ctrl-Button2) and fontMenu (Ctrl-Button3): what xterm does behind it, how much of that lives in libghostty-vt, and how approachable it is for Revenant. Reviewed against the then-selected libghostty headers on 2026-08-25.

Status key: DONE implemented; PARTIAL usable subset with documented gaps; READY can be wired now with no new subsystem; ROADMAP waits on a planned roadmap slice; BLOCKED needs a libghostty change; SKIP recommend not planning (record in the xterm differences ledger).

The tables are maintained per entry; grouped entries do not imply a current aggregate count.

The big pattern¶

About a third of the VT and main menus are DEC private modes. libghostty exposes all of them through ghostty_terminal_set(GHOSTTY_TERMINAL_OPT_MODE) and ghostty_terminal_get(GHOSTTY_TERMINAL_DATA_MODE), and the key encoder re-reads them via ghostty_key_encoder_setopt_from_terminal. The generic XtpTerminalSetMode/XtpTerminalGetMode pair in src/terminal.h now backs autowrap, reversewrap, autolinefeed, appcursor, appkeypad, backarrow key, num-lock and alt-esc, with checkmark state read back from DATA_MODE. Meta-esc still needs a distinct X Meta/Alt policy and allow132 needs grid-size polling after terminal input. Application cursor blinking, its presentation timer, the four-value cursorBlink resource policy, and cursorBlinkXOR are implemented; the menu toggle still needs defined transitions between configured and forced policy.

mainMenu¶

Item	What xterm does	libghostty involvement	Approachability	Status
toolbar	Xaw toolbar (OPT_TOOLBAR, off in most builds)	None	Not worth reproducing	SKIP
fullscreen	Toggle _NET_WM_STATE_FULLSCREEN	None	One EWMH client message	READY
securekbd	XGrabKeyboard+XGrabServer, reverse-video flash	None	Pure Xlib, low value	READY
allowsends	Accept send_event X events	None	Check xany.send_event in handlers	READY
redraw	Full repaint	—	—	DONE
logging	Tee PTY output to logFile, honour logInhibit	None (before vt_write)	One coherent PTY tee with -/+l and -lf; tracked as TODO P1	ROADMAP
print-immediate	Dump screen text (+SGR) to printerCommand	Screen read: ghostty_row_get/cell_get or select_all+selection_format_alloc	Needs a "walk screen as styled text" helper	ROADMAP
print-on-error	Same, from the X I/O error handler	Same	Same walker	ROADMAP
print	Buffered screen dump	Same	Same walker	ROADMAP
print-redir	Printer controller mode (CSI 5 i/4 i)	Ghostty has no media copy; OPT_UNKNOWN_SEQUENCE is APC-only	Needs MC callback or CSI passthrough	BLOCKED
dump-html	Screen with colours as HTML	Screen read + DATA_COLOR_PALETTE	Reuse render walker	ROADMAP
dump-svg	Same as SVG	Same	Same	ROADMAP
8-bit control	S8C1T single-byte C1 output	No encoder/response option	Ask for DRIFT entry instead	BLOCKED
backarrow key	DECBKM	GHOSTTY_MODE_BACKARROW_KEY_MODE (?67)	Mode flip	DONE
num-lock	Ignore keypad app mode with NumLock	GHOSTTY_MODE_NUMLOCK_KEYPAD (?1035)	Mode flip	DONE
alt-esc	altSendsEscape	GHOSTTY_MODE_ALT_SENDS_ESC (?1039)	Mode flip	DONE
meta-esc	metaSendsEscape	GHOSTTY_MODE_ALT_ESC_PREFIX (?1036); Ghostty has one "alt"	Mode flip + decide X Meta/Alt mapping (DRIFT note)	READY
delete-is-del	Delete sends 0x7F	None	Special-case XTP_KEY_DELETE before encoder	READY
oldFunctionKeys	Legacy F-key table	Encoder has one table	Post-mapping table; low value	SKIP
tcapFunctionKeys	Keys from terminfo	None	Needs terminfo layer	SKIP
hpFunctionKeys	HP table	None	Static table	SKIP
scoFunctionKeys	SCO table	None	Static table	SKIP
sunFunctionKeys	Sun table	None	Static table	SKIP
sunKeyboard	VT220 keypad mapping	None	Same family	SKIP
suspend/continue/interrupt/hangup/terminate/kill	kill(-pgrp, SIG*)	None	Six one-liners in pty.c	READY
quit	Exit	—	—	DONE

vtMenu¶

Item	What xterm does	libghostty involvement	Approachability	Status
scrollbar	Show/hide Xaw scrollbar	DATA_SCROLLBAR, scroll_viewport (already wrapped)	Xaw widget, layout, thumb and navigation	DONE
jumpscroll	Batch lines per repaint	None	Render-scheduling knob; subtle drift	READY
reversevideo	Swap fg/bg	—	—	DONE
autowrap	DECAWM	GHOSTTY_MODE_WRAPAROUND (?7)	Mode flip	DONE
reversewrap	Reverse wrap	GHOSTTY_MODE_REVERSE_WRAP (?45)	Mode flip	DONE
autolinefeed	LNM	GHOSTTY_MODE_LINEFEED (20)	Mode flip	DONE
appcursor	DECCKM	GHOSTTY_MODE_DECCKM (?1)	Mode flip	DONE
appkeypad	DECKPAM	GHOSTTY_MODE_KEYPAD_KEYS (?66)	Mode flip	DONE
scrollkey	Keypress snaps to bottom	scroll_viewport	Resource, CLI, and menu policy	DONE
scrollttyoutput	Output snaps to bottom	Same	Resource, CLI, and menu policy	DONE
allow132	Allow DECCOLM resize	GHOSTTY_MODE_ENABLE_MODE_3 (?40); no mode-change callback, poll DATA_COLS after feed	Mode flip + small poll	READY
keepSelection	Keep highlight after loss	None	Roadmap #4	ROADMAP
keepClipboard	Don't clear CLIPBOARD	None	Roadmap #4	ROADMAP
selectToClipboard	Selection owns CLIPBOARD	Xt named-selection ownership	Resource, set-select, and menu policy	DONE
visualbell	Flash	Bell callback exists	Invert + timer	READY
bellIsUrgent	WM urgency hint	Bell callback	XUrgencyHint	READY
poponbell	Raise window	Bell callback	XRaiseWindow	READY
cursorblink	Blink cursor	OPT_DEFAULT_CURSOR_BLINK, DATA_CURSOR_STYLE	Toggle false/true as xterm does; RIS and DECSTR restore the startup four-value policy	READY
titeInhibit	Ignore alt-screen switches	No way to disable a mode handler	Needs "permanently reset mode" option	BLOCKED
activeicon	Terminal in icon window	None	Modern WMs ignore	SKIP
copy_area	Toggle xterm's XCopyArea scroll optimization	None	Revenant does not use xterm's scroll-copy path; see the drift ledger	SKIP
softreset	DECSTR	Pinned Ghostty does not handle CSI ! p	Needs DECSTR support or a soft-reset API	BLOCKED
hardreset	RIS, keep saved lines	ghostty_terminal_reset() clears scrollback	Needs a reset-preserving-history API or a complete local RIS implementation	BLOCKED
clearsavedlines	Reset + drop scrollback	ghostty_terminal_reset() performs RIS and clears scrollback	Add the action and Meta+Button-2 binding; test reset state and DATA_SCROLLBACK_ROWS against xterm	READY
tekshow/tekmode/vthide	Tek 4014 window	None, ever	See Tek section	SKIP
altscreen	Show alternate screen	DATA_ACTIVE_SCREEN; OPT_MODE ?1047 should switch — verify the set path runs the full handler	Probably one call	ROADMAP
sixelScrolling	DECSDM	No sixel in Ghostty	Blocked upstream	BLOCKED
privateColorRegisters	Sixel colour registers	Sixel-only	Blocked	BLOCKED

fontMenu¶

Item	What xterm does	libghostty involvement	Approachability	Status
fontdefault, font1–font7	Font slot	—	—	DONE
fontescape	Font from OSC 50	OSC 50 ignored, not forwarded	Needs unknown-OSC passthrough	BLOCKED
fontsel	Font from PRIMARY	None	Small after Roadmap #4	ROADMAP
allow-bold-fonts	Real bold faces	None; bold flag in XtpRenderCell	Renderer toggle	READY
font-linedrawing	Internal box glyphs	None	Procedural Glyphs label; toggles forceBoxChars for every supported procedural range	DONE
font-packed	Min glyph width for bitmap fonts	None	Cell-metric choice	ROADMAP
font-doublesize	DECDHL/DECDWL	Not in Ghostty	Blocked upstream	BLOCKED
font-loadable	DECDLD soft fonts	Not in Ghostty	Blocked, unused	BLOCKED
render-font	Xft vs bitmap	—	—	DONE
utf8-mode	UTF-8 vs Latin-1	Ghostty is UTF-8 only	iconv possible; recommend permanently on (DRIFT)	BLOCKED
utf8-fonts	utf8Fonts slot set	None	Only meaningful with utf8-mode	ROADMAP
utf8-title	UTF-8 _NET_WM_NAME	Title callback and pop path	utf8Title, set-utf8-title(); EWMH labels written or deleted; entry state follows the locale as in xterm	DONE
allow-color-ops	Gate dynamic-color OSC 10–19 and 110–119	Selector observer enforces the live backend permission	Sets, queries, resets, deny-list exceptions and palette queries gated; remaining differences in drift ledger	PARTIAL
allow-font-ops	Gate OSC 50	No public OSC 50 callback	Policy/resources and menu identity prepared; entry stays insensitive until fontescape	BLOCKED
allow-mouse-ops	Gate mouse and focus reports	Encoder master gate	Live toggle; requested modes preserved; named deny-list exceptions pending	PARTIAL
allow-tcap-ops	Gate XTGETTCAP	Complete generated replies gated at PTY effect	Live toggle and GetTcap deny-list exceptions; TN integration and XTSETTCAP pending	PARTIAL
allow-title-ops	Gate displayed title changes and applying saved labels	Title callback and pop path	Live toggle; OSC 1/icon changes still lack a backend callback; reports use Window Ops	PARTIAL
allow-window-ops	Toggle window-operation permissions	OSC 52 callbacks and title observer	Live selection and title stack/report policy; full Window Ops still pending	PARTIAL

Tektronix 4014¶

In xterm the Tek items drive a second top-level widget (TekWidget, Tekproc.c ≈ 2,100 lines plus TekPrsTbl.c state tables). Nothing about it is a mode of the VT100 engine:

• Separate parser. In Tek mode the PTY byte stream bypasses the VT parser. Switching is by CSI ? 38 h (DECTEK), ESC ^X, ESC ETX, or the menu. libghostty would treat ?38 as unknown and keep consuming bytes as text.
• Vector renderer: four text sizes, vector/point/incremental plot modes, 1024×780 virtual coordinates, persistent display list for redraw.
• GIN mode: crosshair cursor; a keypress sends key plus encoded coordinates.
• Copy: writes the display list as raw Tek escapes to COPY files.

Revenant would have to intercept bytes before XtpTerminalFeed, own a Tek state machine and display list, and add a widget with its own tekMenu. libghostty contributes nothing. xterm's own --disable-tek4014 builds leave the three items insensitive, which is what Revenant does today. Recommendation: record "Tek 4014 not planned" in the xterm differences ledger.

Suggested order¶

1. Slice A: the generic mode helper and eight mode-backed items are complete. Continue with signals ×6; allowsends; visualbell/bellIsUrgent/ poponbell; delete-is-del; and logging. (utf8-title is done.)
2. Slice B, ride the roadmap: scrollbar family with #2; selection policies and fontsel with #4; named Mouse Ops exceptions; allow-bold-fonts and font-packed with #5.
3. Slice C, screen-dump family: one styled-text walker unlocks print, print-immediate, print-on-error, dump-html, dump-svg.
4. Upstream asks, by value: unknown OSC/CSI passthrough (fontescape, print-redir, full XTWINOPS); permanently-reset mode (titeInhibit); effective mouse tracking and OSC 50 hooks. Not worth asking: DECDHL, sixel, DECDLD, S8C1T.
5. Drift-ledger entries: Tek 4014, toolbar, activeicon, copy_area, legacy keyboard tables/sunKeyboard, UTF-8-only, 8-bit controls, soft fonts.