fix(ui): render Warren surfaces at the display pixel ratio

Open

thejustinwalshwants to merge intofrom

A 900×540 Warren window configures a 900×540 GPU attachment on a 2x display, which leaves the native UI blurred when scaled to its 1800×1080 drawable. This keeps layout in logical points and configures the built-in renderer in physical pixels, including clipping and edge antialiasing.

System

Warren selects the display with the largest window overlap and passes its scale to the built-in renderer. Window movement and resizing refresh that choice; a one-second check detects stationary scale changes. pixelRatio accepts a positive, finite number or accessor for an explicit override.

Change

Element	Change	Why
UI mount	Track display scale and invalidate when it changes.	Resize attachments without changing layout, input, or browser anchor coordinates.
Built-in renderer	Round logical size × scale and convert physical fragment positions to logical clips; scale antialiasing width.	Keep clipping and rounded edges aligned with the attachment.
Cocoa window geometry	Convert Y using primary-screen height consistently in `getWindowFrame`, `setWindowPosition`, and `setWindowFrame`, matching `getAllDisplays()`.	Window/display overlap requires one global coordinate space, including vertically arranged displays.

Blast radius

Two direct import dependents: uiTagHost.ts consumes UIMountOptions, and ui/index.ts re-exports the window API. The optional renderer scale argument defaults to 1 for direct internal callers. The Cocoa coordinate correction also affects callers of getWindowFrame outside Warren.

Verify

From package: bun src/preload/build.ts, then node node_modules/typescript/bin/tsc --noEmit: passed.
node scripts/run-bun-test.js src/sdks/main/ui with the pinned Hutch Bun runner: 138 passed, 1 existing Windows-only skip, 0 failed; 1,938 assertions.
Compile the actual Cocoa getter/setter functions in an isolated fixture with synthetic vertically offset screens: the prior branch moved a window by 100 points; the corrected position/frame round-trips pass.
Rebuild the native runtime and check the built-in Warren UI at 1x/2x, fractional scale, scroll clips, and moves between monitors. Verify Cocoa frame coordinates on a secondary display.

Risks

Display selection depends on native window and display geometry using the same coordinate space. The Cocoa correction changes secondary-display Y values for every caller of getWindowFrame.
Scale changes resize the GPU attachment. Input and native browser bounds must continue to use logical dimensions.

Evidence

New pure tests cover 900×540 → 1800×1080 at 2x, fractional rounding, invalid scales, off-screen fallback, largest-overlap selection, and vertically arranged display rectangles.

Unknowns

Full native rendering and real secondary-monitor behavior have not been rebuilt or exercised on this isolated branch. Cocoa coordinate conversion passed the isolated source fixture above. The earlier combined prototype rendered a custom renderer at 2x; that is not validation of this built-in renderer.
Windows/Linux and real mixed-DPI transitions remain untested. No linked issue; #324 concerns WebView2 DPI awareness and #510 concerns Linux nested browser bounds.

Agent context

You are reviewing blackboardsh/electrobun PR #584: https://github.com/blackboardsh/electrobun/pull/584.
A 900×540 Warren window configures a 900×540 GPU attachment on a 2x display, which leaves the native UI blurred when scaled to its 1800×1080 drawable. This keeps layout in logical points and configures the built-in renderer in physical pixels, including clipping and edge antialiasing.
Task: review the isolated change and the adversarial-review corrections against the facts and remaining native-platform limitations.
Facts were collected at the commits below; check each against source before relying on it.
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Review corrections
Cocoa getters and both position/frame setters now share primary-display global coordinates.
Independent adversarial re-review found no remaining P1/P2 issues after these corrections.

Verification
node node_modules/typescript/bin/tsc --noEmit
HUTCH_HOME=/Users/tjw/Developer/agent-deck/.tools/hutch HUTCH_BINARY=/Users/tjw/Developer/agent-deck/.tools/hutch/bin/hutch node scripts/run-bun-test.js src/sdks/main/ui
138 pass, 1 existing skip, 1938 assertions. Actual Cocoa function source fixture passed synthetic screen coordinate round-trips.
Full native runtime rebuild and real multi-monitor/platform execution remain pending; no such coverage is claimed.

Diagram spec
{
  "title": "Warren keeps layout logical and renders physical pixels",
  "type": "component",
  "scope": "native window scale through the built-in Warren renderer",
  "elements": [
    {
      "id": "screen",
      "type": "component",
      "name": "Window and display geometry",
      "technology": "Screen API, Cocoa",
      "description": "Reports rectangles in one logical coordinate space",
      "status": "changed"
    },
    {
      "id": "mount",
      "type": "component",
      "name": "Warren mount",
      "technology": "uiwindow.ts",
      "description": "Chooses and refreshes the display scale",
      "status": "changed"
    },
    {
      "id": "renderer",
      "type": "component",
      "name": "Built-in Warren renderer",
      "technology": "renderer.ts, pixelSize.ts",
      "description": "Scales attachments and converts fragment clips",
      "status": "changed"
    },
    {
      "id": "gpu",
      "type": "component",
      "name": "Native GPU drawable",
      "technology": "Dawn, platform surface",
      "description": "Receives physical attachment dimensions"
    }
  ],
  "relationships": [
    {
      "from": "screen",
      "to": "mount",
      "label": "Supplies logical window bounds and display scales",
      "technology": "FFI, Screen API",
      "status": "changed"
    },
    {
      "from": "mount",
      "to": "renderer",
      "label": "Supplies logical dimensions and pixel ratio",
      "technology": "resize and render arguments",
      "status": "changed"
    },
    {
      "from": "renderer",
      "to": "gpu",
      "label": "Configures rounded physical dimensions and draws",
      "technology": "WebGPU surface and shader",
      "status": "changed"
    }
  ]
}

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Activity

fix(ui): render Warren surfaces at the display pixel ratio

a4e0a2aOct 19

fix(macos): keep window frame getters and setters in one coordinate space

af7d9d6Oct 19

thejustinwalsh11d ago

Addressed adversarial review: both Cocoa position/frame setters now use the same global primary-display coordinate conversion as the getter. The actual-function fixture reproduces a 100-point move on the previous code and passes position/frame round-trips after the fix. Warren tests and package typecheck pass; full native/multi-monitor validation is still pending.