# Multiprompter

what it does

write your script once, run it across as many windows as you want:

• one script, n windows — a markdown editor with live preview drives any number of frameless viewer windows
• precise cross-window scroll sync — every window stays on the same spot, even at different font sizes, because sync is by logical position (a source line plus how far you are through that paragraph), not pixel scroll
• per-viewer font, top-anchored — each window sizes its own text; they match on the top line, which is what actually helps when your screens aren’t physically centered
• persistence — viewers and the editor frame reopen exactly where you left them

why i built it

i record a lot of tutorials and talking-head videos, and i wanted a teleprompter that could run more than one window at once: a large prompter for my face cam and a thin strip sitting over my editor, both scrolling together. every teleprompter i found is single-window. it’s also the standalone, multi-window cousin of linesmith, my vs code teleprompter.

the other reason: it’s my first swift app. i wanted to learn the language by building something real i’d actually use, not a toy.

how it’s built

a quick tour:

• swift + swiftui + appkit — swiftui for the shell, appkit where it counts
• one shared scroll engine — the editor, the preview, and every viewer scroll through the same NSTextView-based line-mapping engine, after swiftui’s scrollPosition proved too coarse and a beat behind
• fractional sync position — the sync unit is line + fraction through the paragraph, so long wrapped paragraphs can’t let two windows drift apart
• echo suppression for “who’s driving” — any window broadcasts as it scrolls and ignores the one scroll it caused by following, which beat the scroll-phase and hover approaches that kept getting stuck
• borderless AppKit windows — viewers are frameless NSWindows, the groundwork for always-on-top and exclude-from-capture later

what’s next

• v1.5 viewer types — teleprompter (large, centered), strip, and window, each with its own defaults
• exclude-from-capture — the strip floats over your code but stays invisible in the screen recording. the killer feature.
• per-viewer opacity, always-on-top, click-through, global hotkeys, layout presets
• a real app icon, and multiprompter.app as the home
• phase 2: voice tracking — your voice drives the same scroll position the windows already share

the windows sharing one position is the whole app. everything after this, voice tracking included, is just another thing that moves that position.