App Store screenshots

SootSim ships an end-to-end pipeline for App Store screenshot production — from capturing raw frames off a live flow, to framing them in real device chrome, to exporting branded marketing canvases in every required size.

Three pieces work together:

#One-shot capture

sootsim screenshot --output hero.png
sootsim screenshot --id loginButton --output button.png
sootsim screenshot --area 0,200,393,400 --output feed.png
sootsim screenshot --gallery --themes                 # crawl + light/dark variants

The live sim keeps running. For clean marketing-ready frames (no browser chrome, no dev rail), flip screenshot mode first:

sootsim screenshot-mode on
sootsim screenshot --output clean.png
sootsim screenshot-mode off

#Batch: the screenshots pipeline

sootsim screenshots runs a YAML plan that can:

1. Boot a sim and run a flow to land on each target screen
2. Capture raw PNGs
3. Frame each raw PNG in real device chrome (bezel, safe-area, Dynamic Island geometry)
4. Compose branded marketing canvases (background gradient, headline text, device pose) in every canvas preset you need

sootsim screenshots --plan .sootsim/app-store.yaml
sootsim screenshots --plan .sootsim/app-store.yaml --sim a9              # reuse live sim
sootsim screenshots --plan .sootsim/app-store.yaml --compose-only         # skip flow, reuse raws
sootsim screenshots --plan .sootsim/app-store.yaml --capture-only         # stop after raws

#Plan shape

A minimal plan:

# .sootsim/app-store.yaml
app: my-app
capture:
  device: iphone-17-pro
  flow: flows/hero-tour.yaml
  slides:
    - id: home
      at: home
    - id: compose
      at: compose-new-post
    - id: feed
      at: feed-scrolled

compose:
  canvases:
    - iphone-6-9
    - iphone-6-7
    - iphone-6-5
  background: dark
  text: bold-top
  pose: straight
  locales:
    - en
    - es
    - ja

One plan file produces slides × canvases × locales framed and composed PNGs, plus a manifest listing every output path for upload to App Store Connect.

#Shared registries

The composer and the live in-shell screenshot mode pull from the same registries — so a slide you compose in the live shell matches what the batch pipeline exports.

• Canvas presets — App Store sizes (6.9”, 6.7”, 6.5”, 5.5”), iPad, custom
• Backgrounds — gradient + glow presets, or custom tokens
• Text presets — headline position, weight, size, color
• Pose presets — straight-on, tilted, multi-device lineup

#Live composition in the shell

Screenshot mode in the browser / Electron shell gives you a WYSIWYG composer:

• Toggle from the MacMenuBar, rail button, or sootsim screenshot-mode on
• Pick a canvas preset, background, text preset, and pose from the in-shell controls
• The device FLIPs into the target canvas rect at the exact export size
• Type headline text inline; see it layout-balanced in the chosen text preset
• Capture with sootsim screenshot --output hero.png — or hit the rail’s capture button

The live state shares canvas / background / text / pose tokens with the batch plan, so whatever you compose live is exportable to the same registry a plan file uses.

#Recording vs screenshots

For video / webm / gif output, use sootsim record instead:

sootsim record --duration 5 --output demo.webm
sootsim record --format mp4 --duration 8 --output demo.mp4
sootsim record --format gif --duration 3 --output demo.gif
sootsim record --frames 10 --output ./frames/          # N evenly-spaced PNGs

See the record reference for full options.

#Related

• sootsim screenshots — batch plan reference
• sootsim screenshot — one-shot capture
• sootsim screenshot-mode — in-shell composer toggle
• sootsim record — video recording