Structural Pattern Taxonomy for MDPR

This note records a source-neutral structural reference analysis used to improve MDPR's deterministic visual-diversification rules. The repository stores only aggregate metrics and derived object grammar. It does not store source names, URLs, downloaded presentations, thumbnails, copied layouts, copied images, or brand-like objects from the reference corpus.

Corpus Scope

Local structural report:

• artifacts/reference-pattern-analysis/derived-object-rules.json
• artifacts/reference-pattern-analysis/structural-summary.json
• downloaded presentation files analyzed locally: 80
• decks analyzed: 80
• slides analyzed structurally: 797
• PowerPoint-rendered PNG slides: 1,594
• PNG samples analyzed: 160
• aggregate objects: 7,530 shapes, 5,726 text frames, 70 tables, 39 charts, 81 pictures

Regenerate the pass with a private or local approved corpus:

npm run reference:rules

The command intentionally requires corpus location environment variables. Source-specific corpus locations are not stored in the repository.

Element Families

Family	Use in MDPR	Coherence guard
Simple shape system	section labels, support panels, number badges, thin accent rules	One radius/border/side-accent grammar per slide. No decorative shape unless it encodes grouping, order, evidence, or emphasis.
Table grid system	comparisons, checklists, validation summaries, risk matrices	Header owns strongest fill; first column may be row-label bold; numeric columns align right; subtle row banding only.
Small icon marker	text-only support, status cue, row marker	Icon stays small, monotone, and secondary. It must not fill empty space or become a large card.
Pictorial metaphor anchor	only when content or provided image justifies a metaphor	Labels anchor to the object; no invented brand-like icons or untracked assets.
Chart proof object	native charts, editable arc/ring proof objects, gauge proof objects, connected strips, trend backdrops	One dominant chart family per slide; labels attach to marks; same-role connectors share one style; background charts remain lower contrast than foreground claims.

Table Coherence Rules

• Strip simple Markdown emphasis markers inside cells before PPT rendering.
• Header row is bold, centered, and uses the strongest theme fill.
• First column is a row-label column and may be bold when the table has two or more columns.
• Numeric columns align right.
• Body rows may use subtle banding from the active surface color.
• Text is vertically centered inside cells.
• Minimum rendered table text size should stay at or above 14pt unless a future explicit appendix mode is introduced.

Text Box Rules

• Preserve semantic bold/italic in paragraph/list rich text.
• Do not emit hard tab characters into PPT text boxes; use deterministic spacing or paragraph-level indentation instead.
• Render plain listItem or plain list entries as separate editable text boxes when PowerPoint rich-text line breaks would collapse adjacent entries.
• Normalize long spaces before measurement and rendering.
• Parent labels should use a font size greater than or equal to child labels. Child emphasis may use bold, but not a larger size.
• Text boxes inside shapes should use middle vertical alignment when the shape is a card, callout, or row label.

Icon Rules

Icons are not a whitespace-filling device.

• Use one icon at most for a text-only support slide.
• Render the icon as a small monotone marker, not a large card.
• Do not use icon slots on chart, table, image, code, or already visually rich slides.
• The icon must be subordinate to title/body hierarchy and should not compete with proof objects.
• When a circle, rounded badge, alphabet marker, number marker, or icon is used like a bullet, the marker shape and the marker text/icon must share the same center point on both axes.
• The adjacent text first-line midpoint must align to the marker center on the vertical axis; reserve a fixed gutter before measuring the text box.

Rule-Based Diversity Roadmap

Accepted implementation families:

• table-grid-system: stronger column width heuristics and appendix mode.
• small-icon-marker: row/status marker variants with fixed max size.
• chart-proof-object: native bar charts plus editable arc-ring, gauge, and connected-strip variants in MDPR PPTX output.
• pictorial-metaphor-anchor: only for provided or detected imagery.
• simple-shape-system: deterministic section labels, rules, and proof callouts.
• derived-object-patterns: 60 reusable object/decorator seeds covering accent rails, tabs, brackets, chips, notches, image sidecars, metric lead cards, connector dots, document metaphors, browser/window frames, speech callouts, timeline rails, hub/spoke diagrams, matrix layouts, chart proof objects, image-caption splits, status tables, and a plain-safe high-density fallback.

Rejected pattern:

• Large decorative icon cards added only to balance empty space. This breaks coherence and creates a template-like look.

Card Decoration Selection Inputs

The seed catalog is selected by rulebase inputs rather than visual copying:

• hasImage: enables image sidecar, caption underlay, and floating label pin styles.
• hasKeyNumber: enables metric lead, rank ribbon, bottom meter, arc corner, and target-ring badge styles.
• importance: reserves stronger treatments for importance 4 or 5.
• textChars: keeps long text in plain-safe, vertical rail, side-notch, or image-sidecar forms.
• relation: distinguishes plain list, sequence, ranking, comparison, proof, constraint, checklist, and flow cards.
• density: prevents decoration from consuming space when readability is the primary risk.

Surface Shape Grammar

MDPR now treats card backgrounds as a small deterministic shape grammar rather than a single rounded rectangle. The renderer can use:

• rounded: safe default fixed-radius card.
• two-corner-left / two-corner-right: two-corner rounding for linear rows, mirrored steps, and side-anchored grouping.
• flag-drop: top-descending flag for method, step, or emphasis cards.
• circle-vine: small circle plus curved connector for related semantic markers.
• notched-corner: clipped or folded corner for proof, data, warning, and code-like panels.
• ticket: side punch marks for document, evidence, checklist, or ticket-like content.

These are generated as SVG-backed PPT surfaces so the visible corner radius remains absolute and coherent across different card sizes. The rulebase selects a family from role, decoration style, item index, relation, density, and importance. It must not add a decorative family when the slide is already crowded or when the shape would compete with charts, tables, images, or proof objects.

Derived Object Pattern Families

The reference pass stores 60 object rules in visual-diversification-seeds.json under derivedObjectPatterns. They are grouped as method vocabulary rather than copied slide templates:

Family	Example object rules	Selection signal
Card/list decorators	accent-rail-card, top-rule-card, number-tab-card, bracket-note-card, plain-safe-card	relation, importance, text length, density
Semantic markers	dot-marker-row, micro-icon-marker, proof-chip-inline, status-dot-table	text-only, status, proof, row labels
Document metaphors	rounded-ticket-panel, paperclip-corner, binder-hole-strip, folded-corner-card, stacked-paper-cards	explicit document/notebook/workbook intent
Diagram systems	horizontal-step-rail, vertical-step-rail, loop-arrow-cycle, center-hub-spokes, axis-quadrant-map, timeline-marker-strip	sequence, cycle, hub, matrix, timeline
Chart proof objects	donut-label-ring, gauge-score-card, small-multiple-bars, trend-line-backdrop, stair-progress-meter	ratio, score, comparison, trend, progress
Image-aware objects	floating-label-pin, caption-underlay, image-sidecar-card, photo-window-mask, image-caption-split, pictorial-anchor-labels	provided image, image caption, metaphor need

Selection rules must still prefer readability over decoration. High-density text, crowded tables, code, and already rich chart/image slides fall back to plain-safe-card or to the native object renderer rather than adding ornament.