fix: rebase cursor samples on capture bounds, use window bounds for picked windows

Implement updateCaptureBounds on MacNativeCursorRecordingSession (optional
on CursorRecordingSession). Samples recorded before the helper reports its
bounds are rebased onto them, and later samples use the new bounds.

For a one-window capture filter on macOS 15.2+, take the capture frame from
kCGWindowBounds by window id instead of filter.contentRect, which sits below
the window's on-screen origin for a window chosen in Apple's picker.

Author: mvanhorn

electron/native-bridge/cursor/recording/macNativeCursorRecordingSession.ts

@@ -234,6 +234,8 @@ export class MacNativeCursorRecordingSession implements CursorRecordingSession {
 	private readyTimer: NodeJS.Timeout | null = null;
 	private previousLeftButtonDown = false;
 	private consecutiveOutsideSamples = 0;
+	private screenPoints: Array<{ x: number; y: number }> = [];
+	private boundsOverride: Rectangle | null = null;
 	// Hide only after this many consecutive out-of-bounds samples (~100ms at 33ms interval).
 	// Fast swipes that briefly exit the display are clipped by clip-path instead of disappearing.
 	private static readonly OUTSIDE_HIDE_THRESHOLD = 3;
@@ -242,6 +244,8 @@ export class MacNativeCursorRecordingSession implements CursorRecordingSession {
 
 	async start(): Promise<void> {
 		this.samples = [];
+		this.screenPoints = [];
+		this.boundsOverride = null;
 		this.assets.clear();
 		this.lineBuffer = "";
 		this.startTimeMs = this.options.startTimeMs ?? Date.now();
@@ -330,6 +334,20 @@ export class MacNativeCursorRecordingSession implements CursorRecordingSession {
 		};
 	}
 
+	updateCaptureBounds(bounds: Rectangle): void {
+		this.boundsOverride = bounds;
+		const width = Math.max(1, bounds.width);
+		const height = Math.max(1, bounds.height);
+		for (let index = 0; index < this.samples.length; index++) {
+			const point = this.screenPoints[index];
+			if (!point) {
+				continue;
+			}
+			this.samples[index].cx = clamp((point.x - bounds.x) / width, 0, 1);
+			this.samples[index].cy = clamp((point.y - bounds.y) / height, 0, 1);
+		}
+	}
+
 	private startPositionOnlyFallback() {
 		this.captureSample(Date.now(), null, null, false, false, false);
 		this.fallbackInterval = setInterval(() => {
@@ -408,7 +426,10 @@ export class MacNativeCursorRecordingSession implements CursorRecordingSession {
 		leftButtonReleased: boolean,
 	) {
 		const cursor = screen.getCursorScreenPoint();
-		const bounds = this.options.getDisplayBounds() ?? screen.getDisplayNearestPoint(cursor).bounds;
+		const bounds =
+			this.boundsOverride ??
+			this.options.getDisplayBounds() ??
+			screen.getDisplayNearestPoint(cursor).bounds;
 		const width = Math.max(1, bounds.width);
 		const height = Math.max(1, bounds.height);
 		const normalizedX = (cursor.x - bounds.x) / width;
@@ -442,9 +463,11 @@ export class MacNativeCursorRecordingSession implements CursorRecordingSession {
 			...(assetId ? { assetId } : {}),
 			...(cursorType ? { cursorType } : {}),
 		});
+		this.screenPoints.push({ x: cursor.x, y: cursor.y });
 
 		if (this.samples.length > this.options.maxSamples) {
 			this.samples.shift();
+			this.screenPoints.shift();
 		}
 	}
 

electron/native-bridge/cursor/recording/session.ts

@@ -1,6 +1,8 @@
+import type { Rectangle } from "electron";
 import type { CursorRecordingData } from "../../../../src/native/contracts";
 
 export interface CursorRecordingSession {
 	start(): Promise<void>;
 	stop(): Promise<CursorRecordingData>;
+	updateCaptureBounds?(bounds: Rectangle): void;
 }

electron/native/screencapturekit/Sources/OpenScreenScreenCaptureKitHelper/ScreenCaptureRecorder.swift

@@ -119,9 +119,7 @@ final class ScreenCaptureRecorder: NSObject, SCStreamOutput, SCStreamDelegate {
 		let filter: SCContentFilter
 		let width: Int
 		let height: Int
-		// Global frame (points, top-left origin) of the captured region. The cursor is
-		// normalised against this, so it is the filter's content rect — the same
-		// rectangle the output buffer is sized from — wherever that exists.
+		// Global frame (points, top-left origin) the cursor is normalised against.
 		let captureFrame: CGRect
 	}
 
@@ -1151,23 +1149,33 @@ final class ScreenCaptureRecorder: NSObject, SCStreamOutput, SCStreamDelegate {
 		return status == .complete
 	}
 
-	/// On-screen rectangle of the pixels this filter will rasterise, in points.
-	///
-	/// `captureSize` already takes its dimensions from `contentRect`: that product is
-	/// the buffer ScreenCaptureKit fills. The cursor is a global Electron point
-	/// normalised against a frame reported separately, so the frame has to be that
-	/// same rectangle, origin included. `SCWindow.frame` and the frame stored with a
-	/// system-picker choice describe the window, which on macOS 26 sits below the
-	/// pixels the stream writes; the pointer then draws above the click (#1130).
-	/// No constant is added here to compensate. `contentRect` is screen points and
-	/// exists from macOS 14. On 13 the source frame is the only measurement available.
+	/// One-window filters use `kCGWindowBounds`: a picker window's `contentRect` sits
+	/// below the pixels the cursor is on (#1130). Displays keep `contentRect`.
 	private func captureContentFrame(for filter: SCContentFilter, fallback: CGRect) -> CGRect {
-		guard #available(macOS 14.0, *) else {
-			return fallback
+		if #available(macOS 15.2, *),
+			filter.includedWindows.count == 1,
+			let windowID = filter.includedWindows.first?.windowID,
+			let bounds = Self.cgWindowBounds(windowID) {
+			return bounds
 		}
+		guard #available(macOS 14.0, *) else { return fallback }
 		return filter.contentRect
 	}
 
+	private static func cgWindowBounds(_ windowID: UInt32) -> CGRect? {
+		guard let entries = CGWindowListCopyWindowInfo(.optionIncludingWindow, CGWindowID(windowID))
+			as? [[String: Any]],
+			let raw = entries.first(where: {
+				($0[kCGWindowNumber as String] as? NSNumber)?.uint32Value == windowID
+			})?[kCGWindowBounds as String] as? NSDictionary
+		else { return nil }
+		var rect = CGRect.null
+		guard CGRectMakeWithDictionaryRepresentation(raw, &rect), rect.width > 0, rect.height > 0 else {
+			return nil
+		}
+		return rect
+	}
+
 	/// Output-buffer size for a filter, capped by the resolution the app asked for.
 	///
 	/// The filter is asked first, because `contentRect × pointPixelScale` is by definition the