gtm-workflow-gif-generation

name	gtm-workflow-gif-generation
description	Generate workflow-style GTM GIFs from validated HTML demo reports using synthetic scene slides plus Playwright/Pillow scroll capture, with Python 3.12 fallback and GIF size optimization.
version	1.0.0
category	workspace-hub-learned
tags	["gtm","gif","playwright","pillow","demo","workflow","digitalmodel"]

GTM Workflow GIF Generation

Use when a demo/report already has a validated HTML artifact and you need a reusable GIF that tells the full story: prompt -> setup -> execution -> report -> browser walkthrough.

When to use

• A report-scroll GIF already exists but is not enough for GTM
• You need one deterministic, reproducible workflow GIF per demo
• The HTML report is already validated and present under examples/demos/gtm/output/

Core pattern

1. Keep the generator local to examples/demos/gtm/media/.
2. Reuse the existing workflow generator structure from another demo if available.
3. Build 5 synthetic HTML scenes with shared dark-theme CSS:
   • prompt
   • repo/code setup
   • analysis execution/progress
   • report/artifact output
   • browser walkthrough label
4. Render those scenes with Playwright headless Chromium.
5. Append a scroll-through of the real validated HTML report by taking a full-page screenshot and cropping viewport-sized frames.
6. Assemble frames into a GIF with Pillow.
7. Update examples/demos/gtm/media/README.md with:
   • deliverable row
   • generation note
   • regeneration command
8. Commit/push the GIF, generator script, and README together.

Important implementation details

• Prefer python3.12 directly if the script imports playwright.sync_api; uv run python may use a Python without Playwright installed.
• For local HTML reports with external Plotly CDN assets, use:
  • page.goto(..., wait_until="domcontentloaded")
  • then page.wait_for_timeout(5000) instead of networkidle, which can hang or fail.
• Keep constants aligned across demos:
  • WIDTH = 1024
  • HEIGHT = 640
  • FRAME_DURATION_MS = 120
  • SCROLL_STEP = 80
• Hold each synthetic slide for several duplicate frames, then insert a few dark transition frames.
• For the walkthrough, do one full-page screenshot and crop it into scrolling frames rather than driving interactive scrolling in real time.

Size-control lesson

If the generated GIF exceeds the repo hook threshold (5 MB), re-quantize it after generation:

• reopen GIF with Pillow
• quantize frames to ~128 colors
• resave with optimize=True This was enough to shrink a 5.4 MB workflow GIF to ~3.6 MB without changing the underlying scene logic.

Minimal file set per demo

• examples/demos/gtm/media/<demo>_workflow.gif
• examples/demos/gtm/media/generate_<demo>_workflow_gif.py
• examples/demos/gtm/media/README.md

Recovery / orchestration lessons

• In tmux/interactive Codex sessions, the useful files may already exist even if the session later hits an Anthropic API 500.
• After any interactive failure, verify externally before retrying:
  • git status --short --branch
  • ls -lh examples/demos/gtm/media/...
• If the artifact exists and only commit/push remains, finish that outside the Codex session instead of rerunning the whole generation.

Good commit pattern

• feat(gtm): add Demo N end-to-end workflow GIF for #2288

Closeout rule

Once all demos in scope have workflow GIFs and README regeneration notes, close the follow-up issue and move downstream to gallery/embed work rather than continuing asset generation.