fix(hud): drop the growth reserve on Linux so the HUD hugs its content

electron/windows.ts

@@ -165,6 +165,22 @@ function hudBounds(win: BrowserWindow): Electron.Rectangle {
 	return { x, y, ...hudWindowSize };
 }
 
+/**
+ * Applies size and position to the HUD. On Linux, `resizable: false` is published to
+ * the window manager as fixed min/max hints, and Mutter then ignores the programmatic
+ * size change — the Linux HUD grows and shrinks as panels open and close (see
+ * LaunchWindow.tsx), so the hints are lifted around the call.
+ */
+function setHudWindowBounds(win: BrowserWindow, next: Electron.Rectangle) {
+	if (process.platform === "linux") {
+		win.setResizable(true);
+		win.setBounds(next, false);
+		win.setResizable(false);
+	} else {
+		win.setBounds(next, false);
+	}
+}
+
 // Origin the current drag gesture started from. The renderer sends the pointer's
 // *total* travel since pointerdown rather than per-frame deltas, so every move is
 // an absolute `origin + delta` — no rounding to accumulate, and a dropped message
@@ -217,7 +233,7 @@ function reclampHud() {
 			})
 		: clampHudBoundsToWorkArea(bounds, hudContentRect, workArea);
 	if (!sameRect(next, bounds)) {
-		win.setBounds(next, false);
+		setHudWindowBounds(win, next);
 	}
 }
 
@@ -435,7 +451,7 @@ ipcMain.on("hud-overlay-set-size", (_event, width: number, height: number, conte
 	hudWindowSize = { width: next.width, height: next.height };
 
 	if (!sameRect(next, bounds)) {
-		hudOverlayWindow.setBounds(next, false);
+		setHudWindowBounds(hudOverlayWindow, next);
 	}
 	reassertAlwaysOnTop(hudOverlayWindow);
 });
@@ -458,11 +474,14 @@ export function createHudOverlayWindow(): BrowserWindow {
 	const primaryDisplay = screen.getPrimaryDisplay();
 	const { workArea } = primaryDisplay;
 
-	// Close to what the renderer asks for on its very first measurement (bar plus
-	// the reserved space above it), so the HUD doesn't visibly resize itself the
-	// instant it becomes visible. See src/components/launch/hudGeometry.ts.
-	const windowWidth = 820;
-	const windowHeight = 560;
+	// Close to what the renderer asks for on its very first measurement, so the HUD
+	// doesn't visibly resize itself the instant it becomes visible. Windows and macOS
+	// ask for the bar plus the reserved space above it; Linux hugs the bar (the HUD
+	// is not click-through there, so a reserve would swallow desktop clicks until the
+	// first measurement). See src/components/launch/hudGeometry.ts.
+	const isLinux = process.platform === "linux";
+	const windowWidth = isLinux ? 600 : 820;
+	const windowHeight = isLinux ? 190 : 560;
 
 	const x = Math.floor(workArea.x + (workArea.width - windowWidth) / 2);
 	const y = Math.floor(workArea.y + workArea.height - windowHeight - 5);

src/components/launch/LaunchWindow.test.tsx

@@ -10,10 +10,12 @@ import type { NativePlatform } from "@/native/contracts";
 import { TooltipProvider } from "../ui/tooltip";
 import {
 	HUD_BAR_BOTTOM,
+	HUD_EDGE_SLACK,
 	HUD_POPOVER_GAP,
 	HUD_POPOVER_MAX_HEIGHT,
 	HUD_STACK_GAP,
 	HUD_TOAST_WIDTH,
+	HUD_TOOLTIP_STACK_HEIGHT,
 	HUD_UNREPORTED_PANELS_ALLOWANCE,
 } from "./hudGeometry";
 import { LaunchWindow } from "./LaunchWindow";
@@ -1286,6 +1288,108 @@ describe("LaunchWindow overlay sizing", () => {
 		);
 	});
 
+	it("grants the bar no growth reserve on Linux", async () => {
+		platformState.value = "linux";
+		renderLaunchWindow();
+
+		const bar = (await screen.findByTestId("hud-drag-handle")).closest(
+			"[data-tray-layout]",
+		) as HTMLElement;
+		stubBox(bar, 400, 56);
+		await flushResizeObservers();
+
+		await waitFor(() => {
+			expect(window.electronAPI.setHudOverlaySize).toHaveBeenCalled();
+		});
+
+		const [width, height] = lastRequestedHudSize();
+		// The bar plus the edge slack, and nothing more: on Linux the HUD is not
+		// click-through, so extra width is a transparent dead zone around the bar.
+		expect(width).toBe(400 + HUD_EDGE_SLACK * 2);
+		// The height keeps room for the tallest tooltip (portalled, so never measured)
+		// and nothing for the panels that are not open.
+		expect(height).toBe(HUD_BAR_BOTTOM + 56 + HUD_TOOLTIP_STACK_HEIGHT + HUD_EDGE_SLACK);
+	});
+
+	it("shrinks back to the bar on Linux once a wider bar narrows", async () => {
+		platformState.value = "linux";
+		renderLaunchWindow();
+
+		const bar = (await screen.findByTestId("hud-drag-handle")).closest(
+			"[data-tray-layout]",
+		) as HTMLElement;
+		stubBox(bar, 520, 56);
+		await flushResizeObservers();
+		await waitFor(() => {
+			expect(lastRequestedHudSize()[0]).toBe(520 + HUD_EDGE_SLACK * 2);
+		});
+
+		stubBox(bar, 400, 56);
+		await flushResizeObservers();
+		// No shrink threshold without a reserve: the window follows the bar down
+		// instead of keeping a click-blocking margin.
+		expect(lastRequestedHudSize()[0]).toBe(400 + HUD_EDGE_SLACK * 2);
+	});
+
+	it("grows for an open panel on Linux and shrinks back once it closes", async () => {
+		platformState.value = "linux";
+		renderLaunchWindow();
+
+		const bar = (await screen.findByTestId("hud-drag-handle")).closest(
+			"[data-tray-layout]",
+		) as HTMLElement;
+		const anchor = bar.parentElement as HTMLElement;
+		const collapsed = HUD_BAR_BOTTOM + 56 + HUD_TOOLTIP_STACK_HEIGHT + HUD_EDGE_SLACK;
+		stubBox(bar, 400, 56);
+		await flushResizeObservers();
+		expect(lastRequestedHudSize()[1]).toBe(collapsed);
+
+		// A 300px panel open above the bar: the window follows its measured height,
+		// so the space is there while the panel is and gone when it is not.
+		const stack = 56 + HUD_POPOVER_GAP + 300;
+		stubBox(anchor, 400, stack);
+		await flushResizeObservers();
+		expect(lastRequestedHudSize()[1]).toBe(HUD_BAR_BOTTOM + stack + HUD_EDGE_SLACK);
+
+		stubBox(anchor, 400, 56);
+		await flushResizeObservers();
+		expect(lastRequestedHudSize()[1]).toBe(collapsed);
+	});
+
+	it("counts a toast in the Linux window height and gives the room back", async () => {
+		platformState.value = "linux";
+		renderLaunchWindow();
+
+		const bar = (await screen.findByTestId("hud-drag-handle")).closest(
+			"[data-tray-layout]",
+		) as HTMLElement;
+		stubBox(bar, 400, 56);
+		await flushResizeObservers();
+		const collapsed = HUD_BAR_BOTTOM + 56 + HUD_TOOLTIP_STACK_HEIGHT + HUD_EDGE_SLACK;
+		expect(lastRequestedHudSize()[1]).toBe(collapsed);
+
+		act(() => {
+			toast.error("Not enough disk space to start recording (only 298 MB free).");
+		});
+		const text = await screen.findByText(/Not enough disk space/);
+		const list = text.closest("[data-sonner-toaster]") as HTMLElement;
+		// Sonner writes the front toast's height on its list once it has measured it;
+		// jsdom has no layout, so the measurement is written here.
+		act(() => {
+			list.style.setProperty("--front-toast-height", "64px");
+		});
+		await waitFor(() => {
+			expect(lastRequestedHudSize()[1]).toBe(collapsed + HUD_STACK_GAP + 64);
+		});
+
+		act(() => {
+			toast.dismiss();
+		});
+		await waitFor(() => {
+			expect(lastRequestedHudSize()[1]).toBe(collapsed);
+		});
+	});
+
 	it("reclaims the overlay once the content drops well below what was granted", async () => {
 		renderLaunchWindow();
 

src/components/launch/LaunchWindow.tsx

@@ -52,9 +52,10 @@ import {
 	computeHudToastsHeight,
 	computeHudWindowSize,
 	HUD_BAR_BOTTOM,
-	HUD_GROWTH_RESERVE,
 	HUD_POPOVER_GAP,
 	HUD_STACK_GAP,
+	HUD_TOOLTIP_STACK_HEIGHT,
+	hudGrowthReserve,
 } from "./hudGeometry";
 import styles from "./LaunchWindow.module.css";
 
@@ -390,9 +391,12 @@ export function LaunchWindow() {
 	// made the HUD flicker and jump the first few times each popover was opened.
 	//
 	// Two rules break it, and both live here:
-	//   1. Only the bar is measured. Everything floating above it has a fixed
-	//      width and a capped height, so its space is *reserved* from the first
-	//      frame — opening a popover costs zero native resizes.
+	//   1. On macOS and Windows, only the bar is measured. Everything floating
+	//      above it has a fixed width and a capped height, so its space is
+	//      *reserved* from the first frame — opening a popover costs zero native
+	//      resizes. On Linux, where the growth reserve is dropped to avoid
+	//      intercepting clicks, the anchor height drives the window size and
+	//      content height changes can resize it.
 	//   2. No measured box may be sized against the viewport. Caps come from
 	//      screen.availHeight (which a window resize can't change) and are pushed
 	//      down as CSS custom properties.
@@ -435,43 +439,64 @@ export function LaunchWindow() {
 			: 0;
 
 		// The two floating surfaces get their own CSS caps (a 470px-tall language
-		// list would look absurd), but the *window* always reserves room for the
-		// taller of them. Sizing the reserve to whichever happens to be open would
-		// mean the window grows when the panel opens — and since the stack is
-		// bottom-anchored, growing upward moves every bit of content down in window
+		// list would look absurd). On Windows and macOS the *window* always reserves
+		// room for the taller of them: sizing the reserve to whichever happens to be
+		// open would mean the window grows when the panel opens — and since the stack
+		// is bottom-anchored, growing upward moves every bit of content down in window
 		// coordinates, which the renderer repaints a frame or two after the native
-		// resize lands. That gap is visible as exactly the position judder this
-		// whole architecture exists to remove. So: reserve the maximum, always.
+		// resize lands. That gap is visible as exactly the position judder this whole
+		// architecture exists to remove. Linux cannot afford that reserve: its HUD is
+		// not click-through, so the empty space intercepts desktop clicks whenever no
+		// panel is open. There the window follows the measured stack instead.
 		const popoverMaxHeight = computeHudPopoverMaxHeight(barHeight, availableHeight);
 		const modalMaxHeight = computeHudModalMaxHeight(barHeight, availableHeight);
 		const anchorEl = hudAnchorRef.current;
 		anchorEl?.style.setProperty("--hud-popover-max-h", `${popoverMaxHeight}px`);
 		anchorEl?.style.setProperty("--hud-modal-max-h", `${modalMaxHeight}px`);
 
+		// Measured after the caps above are applied: the anchor is the whole stack,
+		// bar plus whatever is open above it, so its height is exactly the content
+		// that has to be on screen right now.
+		const anchorRect = anchorEl?.getBoundingClientRect();
+		const stackRect = anchorRect?.width && anchorRect.height ? anchorRect : barRect;
+		const stackHeight = stackRect.height || barHeight;
+
+		const platform = getPlatform();
+		const isLinux = platform === "linux";
+		const growthReserve = hudGrowthReserve(platform);
+		const toastsHeight = hudToastsHeightRef.current;
 		const { required, granted } = computeHudWindowSize({
 			barWidth,
 			barHeight,
-			noticeHeight,
+			// On Linux the measured stack already contains any notice, so counting the
+			// notice again would reserve its height twice.
+			noticeHeight: isLinux ? 0 : noticeHeight,
 			availableHeight,
 			stackMaxHeight: Math.max(popoverMaxHeight, modalMaxHeight),
+			openStackHeight: isLinux
+				? Math.max(HUD_TOOLTIP_STACK_HEIGHT, stackHeight - barHeight)
+				: undefined,
+			toastsHeight,
+			growthReserve,
 		});
 
 		const allocated = hudAllocatedSizeRef.current;
 		// A different orientation is a different shape entirely (wide-short vs
 		// narrow-tall), so the previous allocation says nothing useful.
 		const orientationChanged = allocated.orientation !== trayLayout;
-		// Grow the moment the content stops fitting. Shrink only once the content
-		// has fallen a whole reserve below what was granted — that asymmetry is the
-		// hysteresis: the bar can grow into its reserve (recording controls, a
-		// longer source name) and back out again without a single native resize,
-		// while a one-off bad reading (an unstyled first paint in dev, say) can't
-		// leave the overlay permanently oversized.
+		// Grow the moment the content stops fitting. On Windows and macOS shrink only
+		// once the content has fallen a whole reserve below what was granted — that
+		// asymmetry is the hysteresis: the bar can grow into its reserve (recording
+		// controls, a longer source name) and back out again without a single native
+		// resize, while a one-off bad reading (an unstyled first paint in dev, say)
+		// can't leave the overlay permanently oversized. Linux has no reserve to fall
+		// back into, so it resizes symmetrically and never keeps dead space.
 		const needsResize =
 			orientationChanged ||
 			required.width > allocated.width ||
 			required.height > allocated.height ||
-			granted.width + HUD_GROWTH_RESERVE < allocated.width ||
-			granted.height + HUD_GROWTH_RESERVE < allocated.height;
+			granted.width + growthReserve < allocated.width ||
+			granted.height + growthReserve < allocated.height;
 
 		// The main process keeps this rect on screen, not the window: the window is
 		// mostly transparent reserve, and clamping it would strand the bar at the
@@ -481,15 +506,12 @@ export function LaunchWindow() {
 		// and since the stack is centred and pinned HUD_BAR_BOTTOM above the window's
 		// bottom edge (LaunchWindow.module.css), the rect the granted size will
 		// produce is computed exactly rather than measured a frame late.
-		const anchorRect = anchorEl?.getBoundingClientRect();
-		const stackRect = anchorRect?.width && anchorRect.height ? anchorRect : barRect;
-		const stackHeight = stackRect.height || barHeight;
 		// Toasts sit above the stack, and they are just as visible: a toast pushed off the top
 		// of the screen is an error nobody reads.
 		setHudToastBottom(computeHudToastBottom(stackHeight));
 		const visible = addHudToastsToStack(
 			{ width: stackRect.width || barWidth, height: stackHeight },
-			hudToastsHeightRef.current,
+			toastsHeight,
 		);
 		const contentFor = (size: { width: number; height: number }) => ({
 			x: (size.width - visible.width) / 2,
@@ -528,9 +550,10 @@ export function LaunchWindow() {
 	}, [trayLayout]);
 
 	// One persistent observer; elements wire themselves up via callback refs as
-	// they mount/unmount. The bar and the notice column size the window; the anchor
-	// (the whole stack) only feeds the content rect, so a popover opening costs a
-	// re-clamp but never a native resize.
+	// they mount/unmount. On Windows and macOS, the bar and the notice column size
+	// the window; the anchor only feeds the content rect, so a popover opening
+	// costs zero native resizes. On Linux, the anchor height drives window size
+	// and content height changes can resize it.
 	const hudResizeObserverRef = useRef<ResizeObserver | null>(null);
 	useEffect(() => {
 		const observer = new ResizeObserver(() => measureHudSize());