# Screen-Share UI Fixes (Hotfix)

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Fix two visible bugs in the Discord-style screen-share viewer:
1. **Taskbar abgeschnitten** — when a sender shares their entire monitor, the receiver sees the bottom of the screen (Windows taskbar area) cut off.
2. **Top-right icon overflows its frame** — the small button at the top-right corner of the in-share strip (`StripToggleIcon` / participants-toggle) renders its 2-people SVG too large for its container, with no top/bottom padding.

**Architecture / cause analysis:**

**Bug 1** has TWO possible root causes that both need to be ruled in or out:

- *Sender side (most likely)*: `apps/desktop/src/lib/screenShareSettings.ts` defines fixed `dims` for every non-`auto` preset (e.g. `1080p30` = 1920×1080). `CallContext.tsx:1445-1459` passes those dims as `resolution: { width, height, frameRate }` to LiveKit's `setScreenShareEnabled`. LiveKit forwards them to Chromium's `getDisplayMedia` as exact constraints. When the sender's primary monitor isn't 16:9 (e.g. a common 1920×1200 laptop, a 2560×1600 16:10 panel, a vertical secondary monitor, or a HiDPI scaled display), Chromium *crops* the frame to match — chopping the bottom strip where the Windows taskbar lives. The `auto` preset (`dims: null`) is unaffected because it omits the constraints.
- *Receiver side*: `apps/desktop/src/components/InCallPanel.tsx:1326-1330` reserves `pb-28` (112px) at the bottom of the cinema-mode content area for the floating controls bar, and `ScreenShareViewer.tsx:99-113` uses `object-contain` on the `<video>`. The math already protects against overlap, but worth a visual sanity check during the smoke test.

**Bug 2** is in `apps/desktop/src/components/InCallPanel.tsx:1497-1524` — the `StripToggleIcon` button is `h-9 w-9` (36×36) wrapping an `<svg width="18" height="18">`. The SVG's `viewBox` is `0 0 24 24` but several of its paths actually reach beyond y=24 (`M17 21v-2a4 4 0 0 0-4-4H5a4 4 0 0 0-4 4v2` puts the bottom edge at y=23 and the top at y=11, but combined with `M16 3.13a4 4 0 0 1 0 7.75` the icon extends roughly y=3.13 to y=23 — almost the full viewBox, leaving ~1px padding). At 18×18 that translates to <1px visible breathing room. Combined with any container line-height or rounding, the icon appears to touch the frame edge. Fix: drop the explicit `width="18" height="18"` and let it inherit a Tailwind size class, OR shrink the icon to fit cleanly inside the 36px button.

**Tech Stack:** React 18 + TailwindCSS + LiveKit client. No backend changes.

**Non-goals:**
- Not redesigning the cinema-mode controls layout.
- Not adding a new "fit-to-monitor" preset option (could be a follow-up if cropping is widespread).
- Not changing audio-share behavior.

---

## Pre-flight

- [ ] **Verify clean working tree on `main`**

Run: `cd "D:\Programmieren\ChatApp-Electron\chat-app" && git status`
Expected: only Phase 3 commits ahead of last good baseline; no unrelated uncommitted changes.

---

## Task 1: Diagnose — confirm sender-side cropping vs receiver-side overlay for Bug 1

**Why:** Before changing the preset behavior we want to confirm the symptom matches the hypothesis. The user's screenshot shows the Windows taskbar visible-but-truncated; if the truncation is exactly the height difference between 1080 and the monitor's actual height, the sender-side hypothesis is confirmed.

**Files (read-only):**
- `apps/desktop/src/context/CallContext.tsx:1395-1470` — where the preset dims are passed to LiveKit
- `apps/desktop/src/lib/screenShareSettings.ts` — preset dims table
- `apps/desktop/src/components/InCallPanel.tsx:1320-1410` — cinema-mode layout for receiver

- [ ] **Step 1: Inspect the sender's current preset (in dev / chat with user)**

Ask the user: "Which screen-share preset is set on the sender's machine (Settings → Bildschirmfreigabe → Voreinstellung)? And what's their primary monitor resolution (right-click desktop → Anzeigeeinstellungen → Auflösung)?"

If preset is `auto` → sender-side hypothesis is FALSE; jump to Step 3 (receiver-side investigation).
If preset is anything else (e.g. `1080p30`) AND monitor resolution doesn't match the preset's aspect ratio → sender-side hypothesis is CONFIRMED; proceed to Task 2.

- [ ] **Step 2: Reproduce locally if access exists**

Set a known non-matching configuration:
- Settings → Bildschirmfreigabe → Voreinstellung = `1080p · 30 fps`
- On a monitor with native 1920×1200 (or any non-16:9) resolution
- Start a share with the user's account in a second window
- Observe: bottom of receiver's view should be the cropped band where the taskbar would be

Document the observed monitor resolution + preset in the commit message of Task 2.

- [ ] **Step 3: Inspect receiver-side cinema layout for any overlap regression**

Read `apps/desktop/src/components/InCallPanel.tsx` lines 1324-1485. Verify that:
- The content area has `pb-28` (line 1331 today)
- The control bar's wrapping div has `absolute bottom-4` (line 1528 today)
- `4 + ~80 (controls height) ≈ 84 < 112 (pb-28)` → no overlap

If the math still holds, the receiver-side path is clean and Bug 1 is purely sender-side.

**No commit for this task** — diagnosis only. Findings inform Task 2.

---

## Task 2: Fix — preset dims act as aspect-preserving maxima, not hard crops (Bug 1)

**Why:** The user expects "1080p" to mean *quality cap*, not *forced crop*. A non-16:9 monitor should still stream its entire surface, just scaled to fit within the preset's pixel budget.

**Files:**
- Modify: `apps/desktop/src/context/CallContext.tsx` (the `setScreenShareEnabled` call around line 1438)

Two viable approaches — Task 2 picks Option A; Option B is a fallback if A doesn't work in LiveKit.

### Option A (preferred): drop fixed dims, rely on bitrate cap only

LiveKit's screen-share publish accepts a `videoSimulcastLayers` / `screenShareEncoding.maxBitrate` knob independently of resolution. By only constraining frame rate + bitrate, we let the capture run at native resolution and downscale via encoder.

- [ ] **Step 1: Find the LiveKit screen-share publish call**

Read `apps/desktop/src/context/CallContext.tsx` around line 1438-1465 to confirm the current shape of the `setScreenShareEnabled` options object.

- [ ] **Step 2: Replace the `resolution.{width,height}` block with an aspect-preserving variant**

The current block (lines ~1445-1459):
```ts
...(ssParams.dims
  ? {
      resolution: {
        width: ssParams.dims.width,
        height: ssParams.dims.height,
        frameRate: fps,
      },
    }
  : {
      resolution: {
        width: 3840,
        height: 2160,
        frameRate: fps,
      },
    }),
```

Change to (verify LiveKit option shapes against the current installed version with `pnpm list livekit-client` first — if `screenShareEncoding` isn't supported, fall back to Option B):
```ts
// Preset dims become a max-height cap that the encoder honours via the
// videoEncoding.maxBitrate + frameRate combo. We deliberately do NOT pass
// resolution.width/height to getDisplayMedia — Chromium treats those as
// exact constraints and CROPS non-matching monitors (e.g. 16:10 panels
// lose their bottom strip, including the Windows taskbar).
//
// Quality is still scoped to the preset via the bitrate ceiling configured
// elsewhere in screenShareSettings; we just stop forcing the geometry.
...(ssParams.dims
  ? {
      resolution: {
        frameRate: fps,
      },
    }
  : {
      resolution: {
        frameRate: fps,
      },
    }),
```

If `resolution` requires at least one of `width`/`height` in the installed LiveKit type, pass only the height as `ideal` (not the width) — Chromium will then scale width to preserve aspect:
```ts
resolution: {
  height: { ideal: ssParams.dims.height } as unknown as number,
  frameRate: fps,
},
```
(The `as unknown as number` cast handles a LiveKit type that expects a plain number; the runtime accepts the MediaTrackConstraints object form because it's forwarded to `getDisplayMedia`.)

- [ ] **Step 3: Typecheck + smoke test plan**

Run: `pnpm --filter @chat-app/desktop typecheck`
Expected: PASS. If LiveKit's TS types reject the change, fall through to Option B below.

Smoke test sequence (user-driven; don't need to verify in code):
1. Set preset to `1080p · 30 fps`
2. Share entire primary monitor
3. Receiver sees the full monitor including the taskbar — no crop
4. Switch to a Windows window source → still shares fully
5. Switch preset to `auto` → still works
6. Switch preset to `720p · 30 fps` → bitrate drops, but no crop

### Option B (fallback): keep dims, switch to `ideal` constraints

If Option A doesn't typecheck, replace the resolution block with:
```ts
// `ideal` lets Chromium pick the closest match without cropping when the
// source's native resolution doesn't fit exactly. Using fixed width/height
// causes Chromium to crop non-matching monitors (e.g. 16:10 panels lose
// the bottom strip with the taskbar).
...(ssParams.dims
  ? {
      resolution: {
        width: { ideal: ssParams.dims.width } as unknown as number,
        height: { ideal: ssParams.dims.height } as unknown as number,
        frameRate: fps,
      },
    }
  : {
      resolution: {
        frameRate: fps,
      },
    }),
```

- [ ] **Step 4: Commit (whichever option compiled)**

```bash
git add apps/desktop/src/context/CallContext.tsx
git commit -m "fix(screen-share): preset dims no longer crop non-16:9 monitors"
```

---

## Task 3: Fix — StripToggleIcon padding inside its frame (Bug 2)

**Why:** The participants strip-toggle button (`absolute right-5 top-5` in cinema mode) is `h-9 w-9` (36×36) with an 18×18 SVG whose path data fills nearly the entire viewBox, leaving no visible padding. The icon appears glued to the frame edges.

**Files:**
- Modify: `apps/desktop/src/components/InCallPanel.tsx` (the `StripToggleIcon` function around line 1542-1561)

- [ ] **Step 1: Shrink the icon's actual rendered size**

Read `apps/desktop/src/components/InCallPanel.tsx` lines 1542-1561 to confirm the current SVG shape.

Change the SVG element from:
```tsx
<svg
  width="18"
  height="18"
  viewBox="0 0 24 24"
  ...
>
```
to:
```tsx
<svg
  width="14"
  height="14"
  viewBox="0 0 24 24"
  ...
>
```

Rationale: 14px inside a 36px button leaves 11px of padding on each side (36 − 14 = 22, /2 = 11), matching the visual rhythm of other icon buttons in the same file (e.g. the `FullscreenIcon` in ScreenShareViewer uses `h-3.5 w-3.5` = 14px inside `h-6 w-6` = 24px = ~5px padding, but the cinema strip-toggle is on a larger 36px button and benefits from a similar ratio).

- [ ] **Step 2: Verify visually adjacent icon-buttons match the new ratio**

Skim the file for other `h-9 w-9` buttons and confirm their inner-icon sizes (`grep -n "h-9 w-9" apps/desktop/src/components/InCallPanel.tsx`). If most use ~14px icons, the change is in line; if they use 18px, leave 18 alone and instead fix the SVG's viewBox padding by widening it to `viewBox="-2 -2 28 28"` so the visible content sits in the middle:

```tsx
<svg
  width="18"
  height="18"
  viewBox="-2 -2 28 28"
  ...
>
```

Pick whichever approach the file's existing aesthetic favours. Default to **Step 1's shrink-to-14** unless Step 2's grep proves 18 is the house norm.

- [ ] **Step 3: Typecheck**

Run: `pnpm --filter @chat-app/desktop typecheck`
Expected: PASS (this is a pure JSX change).

- [ ] **Step 4: Commit**

```bash
git add apps/desktop/src/components/InCallPanel.tsx
git commit -m "fix(call): strip-toggle icon no longer touches its frame edges"
```

---

## Final gate

- [ ] **Step 1: Typecheck both packages**

Run: `pnpm --filter @chat-app/shared typecheck && pnpm --filter @chat-app/desktop typecheck`
Expected: both PASS.

- [ ] **Step 2: Run shared tests (sanity — these changes don't touch shared, but confirm no flakes)**

Run: `pnpm --filter @chat-app/shared test --run`
Expected: PASS — same count as before this hotfix.

- [ ] **Step 3: Smoke test in dev (user-driven)**

User starts `pnpm dev`, runs a screen-share to a second account, and verifies:
- Taskbar visible at bottom of the streamed monitor (any preset)
- Strip-toggle button in cinema mode shows the 2-people icon with comfortable padding inside its 36px frame

Report back: "Hotfix code-complete. Restart dev, share your monitor at any preset — taskbar should now stream fully. Cinema-mode strip-toggle button should have visible padding around the icon. **No release** — version stays 0.18.8."

---

## Self-review

1. **Bug coverage:**
   - Bug 1 (taskbar crop) → Task 2 (sender-side preset constraint change)
   - Bug 2 (icon overflow) → Task 3 (SVG size adjustment)
   - Diagnosis Task 1 confirms the root cause before applying fixes

2. **Placeholders:** none.

3. **Risk:** Option A in Task 2 changes the screen-share quality model — bitrate cap remains, but visual fidelity may improve OR encoder may push more bandwidth than before for the same preset name. Acceptable: the previous behaviour cropped content, which is strictly worse. The user can fall back to `720p` if bandwidth becomes an issue.

4. **Aspect-ratio interaction with low-bitrate presets:** `720p · 30 fps` previously enforced a 1280×720 max — a 4K monitor streamed under this preset now passes native 3840×2160 frames to the encoder, capped only by bitrate. The encoder will downscale to stay under the budget, but the receiver renders at the source resolution × encoder scale-factor. If this becomes a CPU/quality concern, re-introduce a height cap via Option B's `ideal` constraints (which Chromium honours preferring aspect ratio over exact match).
