pptx-posters skill

PPTX posters

Scope

Use this skill only when the requested source/deliverable is an editable PowerPoint poster. Do not route an unspecified poster request here merely because PowerPoint is available.

Version 2.0 generates a real one-slide .pptx from strict local JSON. It does not use HTML conversion, external templates, schematic/image-generation services, API keys, environment files, network requests, or mandatory figure styles.

Hard gates

Stop instead of guessing when any gate is unmet:

license, or QR target is unresolved.

1. The author has not supplied exact poster content and source records.
2. Any claim, number, citation, author, affiliation, funding statement, figure,

or is an untrusted template.

1. Current conference and printer requirements are not confirmed.
2. Author approval is not bound to the current manifest content hash.
3. An asset is remote, outside the manifest directory, unhashed, or unapproved.
4. An input is .pptm, contains macros/external relationships/OLE/embedded files,

1. The requested workflow needs PowerPoint to be opened or executed automatically.
2. A script reports a package, layout, DPI, contrast, or output-plan blocker.

Never fabricate missing material or leave a plausible placeholder. Drafts fail closed.

Install exact generation dependencies

From the skill directory:

uv venv
uv pip install "python-pptx==1.0.2" "Pillow==12.3.0" "lxml==6.1.1"

Generation requires exactly:

python-pptx==1.0.2
Pillow==12.3.0
lxml==6.1.1

All CLIs use lazy optional imports, so python -B scripts/.py --help works without these packages. Use -B to avoid bytecode artifacts.

Establish requirements before layout

Record these separately:

an exact source.

• physical trim width/height and orientation;
• bleed on each edge;
• safe margin inside trim;
• PowerPoint canvas width/height;
• uniform physical-artboard/canvas print scale;
• conference maximum dimensions and delivery format;
• printer trim, bleed, margin, scaling, color-mode, and proof requirements;
• final-output font and raster-DPI thresholds, each labeled as a heuristic or tied to

substitution/proof workflow.

• required font faces, workstation availability, embedding permission, and the

There is no universal poster size. Microsoft currently limits each custom PowerPoint dimension to 1–56 inches and uses one size for all slides. If the physical artboard is larger, use a proportional canvas only when the printer confirms scaling.

Read references/posterlayoutdesign.md.

Build the manifest

Copy assets/postermanifesttemplate.json into the project. The template is deliberately invalid until every replacement token, false confirmation, and draft approval is resolved.

Follow references/manifestspec.md and references/postercontent_guide.md.

The manifest requires:

• exact source IDs for document metadata, every element, and every asset;
• author_verified: true on every source;
• author_approved: true on every element and asset;
• local PNG/JPEG paths and lowercase SHA-256 hashes;
• exact provenance and license/permission for every optional image;
• approved alt text and, when needed, a source-bound native long description;
• explicit reading order and design rectangles;
• visible exact fallback URL/text for every local QR image;
• confirmed conference/printer rules;
• declared sRGB contrast pairs and redundant data encoding;
• approval bound to canonical manifest content.

To obtain the content hash after all non-approval fields pass:

python -B scripts/validate_manifest.py poster.json \
  --print-content-hash

Give that exact manifest and hash to the author. Then set approval.status to approved, record approver and offset-aware timestamp, and copy the hash. Any non-approval edit invalidates approval.

Validate the approved manifest and local assets:

python -B scripts/validate_manifest.py poster.json

Audit assets and palette before generation

python -B scripts/inventory_images.py poster.json \
  --output poster.assets.json

python -B scripts/check_palette.py poster.json \
  --output poster.palette.json

python -B scripts/plan_export.py poster.json \
  --output poster.export-plan.json

Effective DPI is pixels divided by final placed inches, not image metadata DPI. The inventory fully decodes bounded images and blocks EXIF/XMP/comments and embedded text/application metadata; strip those offline, then rehash and reapprove the asset. Contrast uses WCAG 2.2 sRGB mathematics; applying those values to a physical poster is a design target, not a standalone conformance claim. Keep color-redundant labels, markers, shapes, patterns, or line styles.

If the printer requires CMYK, the plan blocks print-readiness until a printer-approved conversion/profile and proof exist. Do not claim that a native PowerPoint PDF is CMYK-compliant.

Read references/posterdesignprinciples.md.

Generate the PPTX

Use a new output path:

python -B scripts/generate_poster.py poster.json \
  --output poster.pptx \
  --report poster.generation.json

Generation:

and existing destinations.

• creates a new blank presentation; it never loads a user template;
• sets the approved canvas before adding content;
• uses one native title placeholder, native text boxes, and local pictures;
• preserves image aspect ratio with contain fitting;
• disables text auto-shrink;
• adds elements in approved reading order;
• writes approved picture alt descriptions and explicit text language to PresentationML;
• does not embed fonts, audio, video, OLE, ActiveX, links, or other media;
• removes default printer-settings binary data and normalizes package timestamps;
• inspects the package before and after the alt-text patch;
• refuses overlaps, out-of-bounds shapes, low final font size/DPI, unsafe packages,

It renders exact manifest text. It does not compose, summarize, research, or correct scientific content.

Run final technical audits

python -B scripts/inspect_pptx.py poster.pptx \
  --output poster.package.json

python -B scripts/check_layout.py poster.pptx \
  --manifest poster.json \
  --output poster.layout.json

The package inspector reads bounded ZIP metadata and selected XML only. It never extracts members or opens/executes the presentation. It rejects:

excessive compression ratios;

• every non-.pptx extension, including .pptm;
• packages outside the bounded one-slide generator profile;
• macro/VBA, ActiveX, custom UI, OLE, embedded, executable, and binary parts;
• every external relationship, including remote linked images and hyperlinks;
• unsafe/duplicate ZIP paths, symlinks, encryption, oversized expansion, and

• malformed or entity-bearing inspected XML;
• missing internal relationship targets.

Read references/pptx_security.md.

Manual PowerPoint and accessibility gate

Automation cannot certify accessibility, text rendering, or scientific accuracy. In a fully patched PowerPoint:

equations, overflow, contrast, and all edges.

1. Open only the generated and technically clean file.
2. Run Review > Check Accessibility.
3. Inspect the Reading Order pane and object names.
4. Review every alt text and native long description.
5. Test keyboard and screen-reader navigation.
6. Confirm fonts are installed/licensed; check embedding choices, substitution, glyphs,

1. Verify that color is never the only encoding.
2. Test every QR code and its visible fallback URL/text.
3. Obtain author sign-off on all content and citations.