PPT from Template

Generate presentations by extracting style from a reference template, then building fresh slides with PptxGenJS.

Core principle: Never modify existing PPT XML. Look at the style, then draw from scratch.

Template Management

Template Directory

Default template directory: INLINECODE0

On every invocation:

1. 1. Scan {workspaceDir}/template/ for *.pptx files.
2. If one template found → use it automatically.
3. If multiple templates found → list them and ask user to choose.
4. If none found → tell user to upload a .pptx file or provide a path.

User Upload

Accept .pptx files uploaded by user. Before processing:

• - Size check: reject files > 50 MB with message: "模板文件超过 50MB 限制，请压缩后重试"
• Save to {workspaceDir}/template/ for reuse.

Workflow

Phase 1: Extract Style

CODEBLOCK0

Read style_raw.yaml for exact data (hex colors, font names, font sizes in pt, positions in inches, fill types, line styles). Then read 3-5 page images for semantic understanding (element roles, layout classification).

Extract two levels:

Level	Source	What to Capture
Global	styleraw.yaml	Colors (hex), typography (font/size/weight), decorations
Per-layout

styleraw.yaml + images | Element inventory: type, role, x/y/w/h, style properties |

Element types: text, image, video, shape, line, numbered_list, step_list, tag_group, chart, table.

For images/videos: set placeholder: true with description for user replacement.

Write results to style.yaml. Schema: references/style-schema.md.

Phase 2: Generate PPT

Use the pptx skill (PptxGenJS) to create slides:

1. 1. Read style.yaml for visual parameters.
2. Combine with user content (topic, page count, outline).
3. Generate PptxGenJS JavaScript applying extracted style.
4. Run JS to produce .pptx.
5. QA: convert to images, verify style fidelity.

Large Deck Strategy (>15 pages)

PptxGenJS generation is fast (seconds), but writing the JS code for many slides can hit context/time limits. Mitigate:

Pages	Strategy
≤15	Single generation pass
16-30

Split into 2 JS files: slides 1-15, slides 16-30. Generate sequentially, merge via pptx-merge or generate in one pres object across two code blocks |
| 31-100+ | Generate a slide factory function per layout type, then loop over a content array. One JS file, data-driven |

Slide factory pattern for large decks:

CODEBLOCK1

This keeps code size O(layouts) not O(pages).

Output Size Control

Target output < 20 MB. PptxGenJS output is typically small (100-500 KB for text-only decks). Large files come from embedded images. If output approaches 20 MB:

1. 1. Reduce image resolution/quality in PptxGenJS options.
2. Use placeholders instead of embedded images.
3. Split into multiple files if unavoidable.
4. Warn user: "PPT 接近 20MB 限制，已使用图片占位符，请手动替换"

Placeholder Convention

• - Image: Dark rectangle + dashed gray border + 🖼️ + label + suggestion
• Video: Dark rectangle + dashed red border + ▶️ + label + suggestion

Key Rules

• - Never modify existing PPT XML — always generate from scratch.
• INLINECODE25 is reusable — once extracted, generate unlimited PPTs in the same style.
• Use shrinkText: true in PptxGenJS to auto-fit long text.
• Match slide dimensions exactly from style_raw.yaml (not hardcoded 16:9).

File Convention

CODEBLOCK2

Troubleshooting

Problem	Solution
Template > 50 MB	Ask user to compress or remove embedded media
Output > 20 MB

Use placeholders, reduce image count/resolution | | >30 pages timeout | Use slide factory pattern, data-driven generation | | No template found | Prompt user to upload .pptx or specify path | | Multiple templates | List options, ask user to choose | | Fonts not available | Fall back to Arial/sans-serif; note in output | | Complex gradients | Describe in style.yaml; use background image |