gtm-demo-workflow-gif-generation

name	gtm-demo-workflow-gif-generation
description	Generate GTM demo GIF assets from validated HTML reports, including both report-scroll GIFs and one higher-fidelity workflow-style GIF, while avoiding Playwright/Python environment traps.
version	1.0.0
category	workspace-hub-learned

GTM Demo Workflow GIF Generation

Use when working on digitalmodel/examples/demos/gtm/media/ to produce GIF deliverables for GTM/demo issues like #1809.

When to use

• You already have validated HTML reports under examples/demos/gtm/output/
• You need GIF assets in examples/demos/gtm/media/
• You want either:
  1. simple report-scroll GIFs, or
  2. a richer workflow GIF showing prompt -> setup -> execution -> report -> browser walkthrough

Proven approach

1. Validate reports first

Do not generate GIFs from stale or unvalidated outputs.

Run from digitalmodel/:

PYTHONPATH=examples/demos/gtm:src uv run pytest examples/demos/gtm/tests/test_gtm_demos.py -q

If you need fresh artifacts, rerun demos with --force before GIF work.

2. For report-scroll GIFs, keep it simple

For issue-aligned deliverable names, keep files in:

examples/demos/gtm/media/

If preview GIFs already exist and are acceptable, normalize by renaming/copying to final names instead of regenerating.

3. For comparison-matrix GIFs, use a generator script

Pattern that worked:

• build a lightweight HTML page from comparison JSON files
• render via Playwright
• capture full-page screenshot
• slice into viewport-height frames
• assemble with Pillow or ffmpeg into GIF

Good source files:

• examples/demos/gtm/results/vessel_comparison_matrix.json
• examples/demos/gtm/results/structure_comparison_matrix.json

4. For workflow-style GIFs, compose staged scenes

Best reusable structure:

1. prompt scene
2. setup/command scene
3. execution/progress scene
4. report generation/open scene
5. browser walkthrough scene

Implementation pattern:

• render the first 4 scenes as synthetic HTML slides styled like terminal/UI panels
• then append a real scroll-through of the validated HTML report
• use Playwright for rendering and Pillow for assembly

This gives a deterministic asset without requiring flaky live desktop capture.

Critical pitfalls discovered

Pitfall 1: Python environment mismatch for Playwright

A script with playwright.sync_api may fail under uv run python or the default python3 even though Playwright is installed elsewhere.

What happened:

• Playwright was not available in the default interpreter path used by one run
• it was available in python3.12

Verification command:

python3.12 -c "from playwright.sync_api import sync_playwright; print('OK')"

Fix:

• use an explicit shebang like:

#!/usr/bin/env python3.12

• or run the generator explicitly with python3.12

Pitfall 2: networkidle can hang on local HTML reports using Plotly CDN

For local file-based HTML reports that load Plotly from CDN, this pattern can fail:

page.goto(...)
page.wait_for_load_state("networkidle")

Why:

• CDN fetches / background activity prevent a clean networkidle state

Fix that worked:

page.goto(url, wait_until="domcontentloaded")
page.wait_for_timeout(5000)

Use a timed wait after domcontentloaded to let Plotly render.

Pitfall 3: External verification matters more than Codex's claim

When using interactive Codex in tmux:

• let Codex implement
• then independently verify with:

git status --short --branch
git log --oneline -3
ls -lh examples/demos/gtm/media/*

Do not trust completion claims without checking the actual files and commit.

Recommended workflow with interactive Codex

When the user explicitly wants Codex:

1. write a tight prompt to /tmp/...txt
2. launch tmux + Codex with:

Codex --setting-sources user --dangerously-skip-permissions "$(cat /tmp/prompt.txt)"

3. monitor with tmux capture-pane
4. if Codex gets stuck, interrupt and send a narrower corrective prompt
5. after completion, verify externally and update GitHub yourself if needed

Good outputs to leave behind

• final GIF assets in examples/demos/gtm/media/
• reproducible generator script(s) in the same folder
• media/README.md documenting what each asset is and how to regenerate it

Workflow-upgrade wave pattern that proved reusable

After the first true workflow exemplar works, upgrade the remaining demos one-by-one instead of trying to regenerate all five in a single fragile run.

Recommended pattern:

1. one tmux/Codex session per demo
2. one generator script per demo, e.g.:
   • generate_demo_01_workflow_gif.py
   • generate_demo_03_workflow_gif.py
   • generate_demo_04_workflow_gif.py
   • generate_demo_05_workflow_gif.py
3. update media/README.md after each successful asset
4. verify file size and visual output externally before closing the issue

This isolates failures and makes it easy to salvage finished files even if one interactive Codex session later hits an upstream API error.

Size-control finding for workflow GIFs

A workflow GIF can easily exceed a practical sharing limit if you keep too many colors or frames.

Recovery pattern that worked:

• re-open the generated GIF with Pillow
• quantize/re-save at lower color count (128 colors worked)
• verify the optimized output still looks acceptable

Use this when a workflow GIF lands over the target size threshold. In the validated run, this was necessary for Demo 4 and brought the file under 5 MB without regenerating the whole asset from scratch.

Suggested follow-up issue split

If a parent issue asked for all GIFs but you only produced one true workflow exemplar plus simpler report-scroll GIFs:

• close parent if named deliverables exist
• create follow-up issue for upgrading remaining demos to workflow-style format

This avoids scope creep while preserving momentum.

If the follow-up issue is approved, execute the remaining upgrades as a wave of small, independent demo-specific tasks rather than reopening the original issue.

Downstream website/gallery packaging finding

Do not automatically publish the large workflow GIFs on a public gallery page.

Better pattern for a marketing/gallery surface:

• copy the 5 lightweight primary demo GIFs plus demo_comparison_matrix.gif
• exclude the larger _workflow.gif files from the page bundle
• use loading="lazy" on below-the-fold media

Why:

• the lightweight set stayed around ~5.3 MB total for the gallery
• including all workflow GIFs would have pushed the page toward ~25 MB+
• workflow GIFs are excellent proof assets, but not ideal default web-gallery payloads

For aceengineer-website, the working implementation pattern was:

• add page source at content/demos/index.html
• copy gallery assets into assets/img/demos/
• run the site build so dist/demos/index.html is produced
• locally serve dist/ and browser-verify the built page, not just the source file