Feature request: user-adjustable UI scale / font size in Settings

[joshleethecreator]

Summary

There is currently no way for a user to increase the UI/font size in the desktop app. On a high-resolution display the interface reads quite small, and none of the usual escape hatches work. I'd like a UI scale (or font size) control in Settings.

Why the existing mechanisms don't cover this

The desktop app already computes a renderer zoom factor in desktop/window-scale.ts, but it is deliberately one-directional:

// desktop/window-scale.ts:70
const fittedScale = Math.min(
  1,
  validDimension(contentWidth) / baselineWidth,
  validDimension(contentHeight) / baselineHeight,
);

Because it is clamped to Math.min(1, …), the factor can only ever shrink the UI (floor DESKTOP_MIN_SCALE = 2 / 3, line 3) when the window gets smaller than its startup canvas. Enlarging the window never enlarges the UI above 100%.

A few related observations:

1. No zoom accelerators. No application menu is built (desktop/main.ts:407 only pops a context menu), so Electron's stock Ctrl++ / Ctrl+- zoomIn/zoomOut menu roles never get registered.
2. Manual zoom doesn't stick. installResponsiveWindowScale re-applies setZoomFactor on every resize (desktop/window-scale.ts:118), so a zoom level set by any other means is overwritten on the next resize event.
3. A CSS-level fix wouldn't be enough. The styling is predominantly hardcoded pixels — roughly 168 font-size: Npx declarations against ~34 in rem across src/. Changing a root font-size would rescale only a small fraction of the interface and leave the rest, so this likely wants to be a zoom-factor feature rather than a typography one.

Proposed behavior

A user-set scale multiplier in Settings (something like 80%–150%), persisted with the other app settings, that feeds into resolveDesktopWindowScale — for example composing with the fitted scale rather than being capped at 1, so the automatic shrink-to-fit behavior is preserved while allowing values above 100%. Bonus: register zoomIn/zoomOut/resetZoom accelerators alongside it.

Current workaround

Launching Electron with Chromium's device scale factor works and does not fight the existing logic, because installResponsiveWindowScale captures its baseline from the window at startup, so fittedScale still begins at 1:

electron --force-device-scale-factor=1.25 desktop-dist/main.mjs

That's fine when running from source, but it isn't reachable for anyone using a packaged build.

Environment

• OpenChatCut v0.2.3
• Linux (Ubuntu 24.04, GNOME/Wayland)
• Electron 43.1.1, running from source

[0xsline]

Implemented and shipped in v0.2.5:

• Settings → 界面 → 显示 → 界面缩放: 80% / 90% / 100% / 110% / 125% / 150%, persisted in the keystore.
• The user scale composes with the existing shrink-to-fit scaling (your window-scale.ts analysis was correct — Math.min(1, …) capped growth; the user scale now multiplies on top while the automatic shrink still applies).
• Ctrl/Cmd + Plus/Minus steps 5%, Ctrl/Cmd + 0 resets; steps persist and re-apply immediately.
• Zoom shortcuts are desktop-only by design; browsers keep their native zoom.

Please verify on the v0.2.5 desktop build — especially the 100% default being bit-for-bit identical to the old behavior (covered by window-scale.verify), and the compose behavior at small window sizes.