feat(Zoom): Live Zoom mode — real-time screen magnification by yusufk · Pull Request #32 · 07JP27/ZoomacIt

yusufk · 2026-05-23T20:53:45Z

Summary

Implements Live Zoom using ScreenCaptureKit's SCStream for continuous 60fps frame capture with real-time pan/zoom controls.

Changes

New hotkey: ⌃⇧1 (Control+Shift+1) activates Live Zoom
Real-time screen content updates (videos, terminals, animations keep playing)
Mouse movement pans the zoomed viewport
Scroll wheel / ↑↓ arrow keys zoom in/out (1.0x–8.0x range)
Click enters Draw mode (freezes current frame as snapshot)
Escape / right-click exits
Own overlay window excluded from capture to prevent infinite mirror effect
Zero-copy rendering via IOSurface for GPU-backed display

Technical Details

LiveZoomWindowController manages SCStream lifecycle and overlay window
LiveZoomView renders frames via CALayer.contents with ZoomMath contentsRect
Stream excludes all app-owned windows (queried after overlay creation)
Reuses existing OverlayWindow, ZoomMath, and Settings infrastructure
Default hotkey stored in UserDefaults, configurable via Settings

Also included

Lowered deployment target from macOS 26 to macOS 15 (all APIs available since macOS 13+)
Clarified contributor build instructions in README

Testing

Verified on macOS 15.7.7 (Sequoia)
Confirmed: live content updates, pan/zoom controls, Draw mode transition, no infinite mirror

All APIs used (ScreenCaptureKit, SCScreenshotManager, CGPreflightScreenCaptureAccess) are available since macOS 13+. Allows contributors on current macOS to build and run.

Unsigned builds fail with -10825 on macOS. Contributors must set their own team ID in project.yml for a valid code signature.

Implements Live Zoom using ScreenCaptureKit SCStream for continuous 60fps frame capture with pan/zoom controls. - New hotkey: ⌃⇧1 (Control+Shift+1) activates Live Zoom - Real-time screen content updates (videos, terminals keep playing) - Mouse movement pans, scroll wheel/arrow keys zoom in/out - Click enters Draw mode (freezes current frame) - Escape/right-click exits - Own overlay window excluded from capture to prevent infinite mirror - Zero-copy rendering via IOSurface for GPU-backed display New files: - LiveZoomWindowController.swift — SCStream lifecycle and window management - LiveZoomView.swift — CALayer-based rendering with ZoomMath integration Modified: - AppDelegate: toggleLiveZoomMode() with Draw mode transition - HotkeyManager: Live Zoom hotkey registration (ID 3) - Settings: liveZoomHotkeyKeyCode/Modifiers with ⌃⇧1 default - README: Feature coverage updated

Copilot

Pull request overview

Adds a new “Live Zoom” overlay mode to ZoomacIt, implementing real-time magnification by streaming screen frames via ScreenCaptureKit and rendering them in an overlay with pan/zoom controls.

Changes:

Introduces LiveZoomWindowController + LiveZoomView to manage SCStream capture and render frames via CALayer.contents (IOSurface-backed).
Adds a new global hotkey (⌃⇧1) and persists its keycode/modifiers in Settings.
Lowers the macOS deployment target to 15.0 and updates project/docs (README + design plan).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/ZoomacIt/Overlay/LiveZoomWindowController.swift	New controller to start/stop `SCStream`, exclude app windows, and feed frames to the view.
src/ZoomacIt/Overlay/LiveZoomView.swift	New view to display live frames and implement pan/zoom + exit/enter-draw inputs.
src/ZoomacIt/Models/Settings.swift	Adds persisted defaults/getters for the Live Zoom hotkey.
src/ZoomacIt/Core/HotkeyManager.swift	Registers/unregisters the new Live Zoom hotkey and routes callbacks.
src/ZoomacIt/App/AppDelegate.swift	Wires the new hotkey to a Live Zoom mode toggle and coordinates mode transitions.
src/ZoomacIt.xcodeproj/project.pbxproj	Adds new source files to the project and lowers deployment target to macOS 15.0.
src/project.yml	Lowers deployment target to macOS 15.0 for xcodegen generation.
README.md	Marks Live Zoom as complete and adds contributor build/signing guidance.
design/LiveZoom-implementation-plan.md	Adds an implementation plan/design note for Live Zoom.

- Move SCStream output to dedicated serial queue to avoid starving UI event handling at 60fps (dispatch only layer update to main) - Set showsCursor=false to prevent double cursor (captured + system) - Replace fragile 50ms sleep with retry loop for window exclusion - Clamp initial zoomLevel to min/max range - Add Live Zoom hotkey keys to resetToDefaults() - Assign liveZoomController before showLiveZoom() so onShowFailed can properly clear the reference

yusufk · 2026-05-24T13:03:45Z

Addressed Copilot review feedback in commit 7e74ebd:

✅ Controller assignment order — liveZoomController assigned before showLiveZoom() so onShowFailed can clear it
⏭️ Draw→LiveZoom transition — noted, will address if it causes issues in practice (current mode dismissal logic handles this)
✅ SCStream on main queue — moved to dedicated serial queue, only layer.contents update dispatched to main
✅ Double cursor — set showsCursor = false
✅ Fragile 50ms sleep — replaced with retry loop (up to 10×20ms) checking for our window in shareable content
✅ Zoom level clamping — initial value now clamped to min/max range
✅ resetToDefaults() — Live Zoom hotkey keys added to reset list
ℹ️ Settings UI — hotkey is configurable via UserDefaults; full Settings UI will come with the Snip PR which adds a General tab for all hotkeys
ℹ️ Tests — will add in a follow-up (SettingsTests extension)

yusufk · 2026-05-24T13:21:25Z

Merge order note

These 4 PRs are now fully independent (each branched from main), but they all add to the same shared files (Settings.swift, HotkeyManager.swift, AppDelegate.swift, StatusBarController.swift). When merging sequentially, you'll hit additive conflicts that are trivial to resolve (just keep both sides).

Recommended merge order (least conflicts):

feat(Zoom): Live Zoom mode — real-time screen magnification #32 Live Zoom ← merge first (largest feature, no conflicts with main)
feat(Draw): pen cursor matches colour, size, and active shape tool #35 Draw Cursor ← no shared-file conflicts (only touches DrawingCanvasView.swift)
feat: DemoType mode — simulated typing for demos #33 DemoType ← additive conflicts in shared files (keep both)
feat: Snip mode — region screenshot to clipboard #34 Snip ← additive conflicts in shared files (keep both)

I've verified all 4 build independently and combine correctly. Happy to squash them into a single PR if you'd prefer a cleaner merge.

- Clear zoomSourceForDrawReturn before dismissing Draw mode when entering Live Zoom, preventing brief Still Zoom restoration Also adds SettingsTests for Live Zoom hotkey: - testDefaultLiveZoomHotkey (⌃⇧1) - testLiveZoomHotkeyRoundTrip - testLiveZoomHotkeyIndependentOfOtherHotkeys - testLiveZoomHotkeyResetToDefaults All 148 tests pass.

yusufk · 2026-05-24T15:55:29Z

The deployment target of 15.0 is a minimum — it still builds and runs perfectly on macOS 26. This just allows users on older macOS versions to use the app too.

07JP27 · 2026-05-24T23:27:50Z

The deployment target of 15.0 is a minimum — it still builds and runs perfectly on macOS 26. This just allows users on older macOS versions to use the app too.

@yusufk
Thanks, and you're right that it still builds and runs on macOS 26. My concern is a bit different, though.

The deployment target controls what builds, but what I really care about is the support guarantee of the released app. My only test environment is macOS 26, so I can verify that the app behaves to spec on 26, but I have no way to test 15 through 25. This app leans heavily on version-sensitive APIs, and these areas have changed behavior across macOS releases before. So "the API exists since macOS 13" doesn't fully reassure me that it works correctly on every version in between.

That said, I don't think we have to choose between "revert to 26" and "guarantee 15–26." I'd be fine keeping the target at 15 as long as we clearly separate the build floor from the support scope — i.e. document in the README that the minimum build target is macOS 15, but the app is tested and officially supported on macOS 26 only, with earlier versions working possibly but not guaranteed.

That way contributors on current macOS can still build and run, and I'm not on the hook for versions I can't test. Would you be okay with that approach?

yusufk · 2026-05-25T10:59:13Z

Hi,

Thanks for the feedback and I understand the concern. I also agree with the approach and will adjust the readme when I get a moment.

Just a note though, Apple went straight from MacOS 15 to 26, with 15 still likely being the most prominent version out in the market.

Thanks
Yusuf

yusufk · 2026-05-25T19:03:58Z

Done — updated the README to clarify: minimum build target is macOS 15, but officially supported on macOS 26 only. See commit 470cbef.

Add Live Zoom feature documentation to the VitePress docs site: - Add Live Zoom hotkey and feature description to usage pages (EN/JA) - Add Live Zoom section to zoom usage pages with controls and comparison table vs Still Zoom (EN/JA) - Update index page Zoom feature description Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

07JP27 · 2026-05-25T23:04:07Z

Done — updated the README to clarify: minimum build target is macOS 15, but officially supported on macOS 26 only. See commit 470cbef.

Thanks, I've updated the README and docs（include Japanese version） to reflect your changes.

07JP27

@yusufk Could you take a look at my review comments? If these changes were intentional, please feel free to let me know.

…ure, reuse CIContext

yusufk · 2026-05-26T17:02:12Z

Addressed all three review comments in commit 1546d17:

✅ Live Zoom hotkey changed to Ctrl+4 (matches Windows ZoomIt)
✅ Stream failure now calls dismiss() before onShowFailed() — no orphaned overlay window
✅ CIContext is now a lazy property instead of allocating per-call

…Zoom, ⌃7 DemoType)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

07JP27 · 2026-05-27T11:40:16Z

Fixed minor issues.

yusufk added 3 commits May 23, 2026 17:47

fix: lower deployment target from macOS 26 to 15

e4924f9

All APIs used (ScreenCaptureKit, SCScreenshotManager, CGPreflightScreenCaptureAccess) are available since macOS 13+. Allows contributors on current macOS to build and run.

docs: clarify contributor build instructions

6dfb6c4

Unsigned builds fail with -10825 on macOS. Contributors must set their own team ID in project.yml for a valid code signature.

07JP27 requested a review from Copilot May 24, 2026 03:38

Copilot started reviewing on behalf of 07JP27 May 24, 2026 03:39 View session

Copilot AI reviewed May 24, 2026

View reviewed changes

feat(Settings): add Live Zoom hotkey to General tab

3656f0e

07JP27 reviewed May 24, 2026

View reviewed changes

Comment thread src/project.yml

docs: clarify macOS support scope (builds on 15+, supported on 26)

470cbef

update readme

8351725

07JP27 requested changes May 25, 2026

View reviewed changes

Comment thread src/ZoomacIt/Models/Settings.swift Outdated

Comment thread src/ZoomacIt/Overlay/LiveZoomWindowController.swift

Comment thread src/ZoomacIt/Overlay/LiveZoomWindowController.swift Outdated

fix(LiveZoom): address review — Ctrl+4 hotkey, dismiss on stream fail…

1546d17

…ure, reuse CIContext

yusufk and others added 5 commits May 26, 2026 19:11

fix(LiveZoom): align GeneralTab default to Ctrl+4

81aa402

docs: update hotkey references to match Windows ZoomIt spec (⌃4 Live …

3d60c3b

…Zoom, ⌃7 DemoType)

feat(LiveZoom): add Live Zoom item to status bar menu

162c4da

fix: align Live Zoom hotkey references

d34bb6d

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fix Live Zoom polish issues

a319c89

07JP27 self-requested a review May 27, 2026 11:40

07JP27 approved these changes May 27, 2026

View reviewed changes

07JP27 merged commit 8d52717 into 07JP27:main May 27, 2026
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yusufk commented May 23, 2026

Summary

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yusufk commented May 24, 2026

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Merge order note

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07JP27 commented May 27, 2026 •

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