PDF Generator When to Use This Skill
Use this skill when:
Creating PDF documents programmatically from data or specifications Filling PDF forms with dynamic data Adding watermarks, stamps, or overlays to existing PDFs Extracting text and metadata from PDF files Merging multiple PDFs into one document Analyzing PDF structure and form fields
Do NOT use this skill when:
User wants to open/view PDFs (use native PDF viewer) Complex page layout with flowing text is needed (consider HTML-to-PDF tools) Working with password-protected PDFs (limited support) OCR is needed for scanned documents Prerequisites Deno installed (https://deno.land/) Input PDF files for template-based operations JSON specification for scratch generation Quick Start Two Modes of Operation
Template Mode: Modify existing PDF templates
Fill form fields (text, checkbox, dropdown) Add overlays (text, images, shapes) Merge and combine PDFs
Scratch Mode: Create PDFs from nothing using JSON specifications
Instructions Mode 1: Template-Based Generation Step 1a: Analyze the Template
Extract form fields and structure from an existing PDF:
deno run --allow-read scripts/analyze-template.ts form-template.pdf > inventory.json
Output (inventory.json):
{ "filename": "form-template.pdf", "pageCount": 2, "title": "Application Form", "author": "Company Inc", "pages": [ { "pageNumber": 1, "width": 612, "height": 792, "text": "..." } ], "formFields": [ { "name": "FullName", "type": "text", "value": "" }, { "name": "Email", "type": "text", "value": "" }, { "name": "AgreeToTerms", "type": "checkbox", "value": false } ], "placeholders": [ { "tag": "{{DATE}}", "location": "page 1", "pageNumber": 1 } ], "hasFormFields": true }
Step 1b: Create Fill Specification
Create form-data.json:
{ "formFields": [ { "name": "FullName", "value": "John Smith" }, { "name": "Email", "value": "john@example.com" }, { "name": "AgreeToTerms", "value": true } ], "flattenForm": true }
Step 1c: Generate Filled PDF deno run --allow-read --allow-write scripts/generate-from-template.ts \ form-template.pdf form-data.json filled-form.pdf
Adding Overlays (Watermarks, Stamps)
Create watermark-spec.json:
{ "overlays": [ { "type": "text", "page": 1, "x": 200, "y": 400, "text": "CONFIDENTIAL", "fontSize": 48, "color": { "r": 1, "g": 0, "b": 0 }, "rotate": 45 }, { "type": "image", "page": 1, "x": 450, "y": 700, "path": "logo.png", "width": 100, "height": 50 } ] }
Merging PDFs
Create merge-spec.json:
{ "prependPdfs": [ { "path": "cover-page.pdf" } ], "appendPdfs": [ { "path": "appendix-a.pdf", "pages": [1, 2, 3] }, { "path": "appendix-b.pdf" } ], "excludePages": [5, 6] }
Mode 2: From-Scratch Generation Step 2a: Create Specification
Create spec.json:
{ "title": "Quarterly Report", "author": "Finance Team", "pages": [ { "size": "A4", "elements": [ { "type": "text", "x": 50, "y": 750, "text": "Q4 2024 Financial Report", "fontSize": 28, "font": "HelveticaBold", "color": { "r": 0, "g": 0, "b": 0.5 } }, { "type": "line", "startX": 50, "startY": 740, "endX": 550, "endY": 740, "thickness": 2 }, { "type": "text", "x": 50, "y": 700, "text": "Executive Summary", "fontSize": 18, "font": "HelveticaBold" }, { "type": "text", "x": 50, "y": 670, "text": "This quarter showed strong growth across all divisions...", "fontSize": 12, "maxWidth": 500, "lineHeight": 16 } ] } ] }
Step 2b: Generate PDF deno run --allow-read --allow-write scripts/generate-scratch.ts spec.json output.pdf
Examples Example 1: Fill Application Form
Scenario: Automatically fill a job application form.
1. Analyze form to find field names
deno run --allow-read scripts/analyze-template.ts application.pdf --pretty
2. Create form-data.json with applicant info
3. Generate filled form
deno run --allow-read --allow-write scripts/generate-from-template.ts \ application.pdf form-data.json john-smith-application.pdf
Example 2: Add Approval Stamp
Scenario: Add an "APPROVED" stamp to a document.
stamp-spec.json:
{ "overlays": [ { "type": "rectangle", "page": 1, "x": 400, "y": 700, "width": 150, "height": 50, "color": { "r": 0.9, "g": 1, "b": 0.9 } }, { "type": "text", "page": 1, "x": 410, "y": 720, "text": "APPROVED", "fontSize": 20, "font": "HelveticaBold", "color": { "r": 0, "g": 0.5, "b": 0 } }, { "type": "text", "page": 1, "x": 410, "y": 705, "text": "2024-12-15", "fontSize": 10 } ] }
Example 3: Create Report with Table
Scenario: Generate a simple report with a data table.
report-spec.json:
{ "title": "Sales Report", "pages": [{ "size": "Letter", "elements": [ { "type": "text", "x": 72, "y": 720, "text": "Monthly Sales Report", "fontSize": 24, "font": "HelveticaBold" }, { "type": "table", "x": 72, "y": 680, "rows": [ ["Product", "Units", "Revenue"], ["Widget A", "150", "$15,000"], ["Widget B", "75", "$11,250"], ["Widget C", "200", "$8,000"] ], "columnWidths": [150, 80, 100], "rowHeight": 25, "headerBackground": { "r": 0.9, "g": 0.9, "b": 0.9 } } ] }] }
Script Reference Script Purpose Permissions analyze-template.ts Extract text, metadata, form fields from PDF --allow-read generate-from-template.ts Fill forms, add overlays, merge PDFs --allow-read --allow-write generate-scratch.ts Create PDF from JSON specification --allow-read --allow-write Element Types (Scratch Mode) Type Description Key Options text Text content x, y, text, fontSize, font, color, rotate image PNG/JPEG images x, y, path, width, height, opacity rectangle Filled/outlined rectangles x, y, width, height, color, borderColor line Straight lines startX, startY, endX, endY, thickness circle Filled/outlined circles x, y, radius, color, borderColor table Basic table layout x, y, rows, columnWidths, rowHeight Available Fonts Helvetica (default) HelveticaBold HelveticaOblique TimesRoman TimesBold Courier CourierBold Page Sizes A4 (595.28 x 841.89 points) Letter (612 x 792 points) Legal (612 x 1008 points) Custom: [width, height] in points Common Issues and Solutions Issue: Form fields not found
Symptoms: Error saying field name doesn't exist.
Solution:
Run analyze-template.ts to get exact field names Field names are case-sensitive Some PDFs have non-fillable text that looks like form fields Issue: Text positioning is off
Symptoms: Text appears in wrong location.
Solution:
PDF coordinates start from bottom-left (0,0) Y increases upward, X increases rightward Use analyze-template.ts to see page dimensions Issue: Images not appearing
Symptoms: Image overlay not visible.
Solution:
Check file path is relative to spec.json location Verify image is PNG or JPEG format Ensure coordinates are within page bounds Issue: Merged PDF has wrong page order
Symptoms: Pages appear in unexpected order.
Solution:
prependPdfs add pages before template appendPdfs add pages after template Use pages array to select specific pages: [1, 3, 5] Limitations No built-in table layout: Tables require manual column width specification Standard fonts only: Custom font embedding not supported in scratch mode No flowing text: Text doesn't automatically wrap to next page Limited form field creation: Can fill existing forms, not create new fields No encryption: Cannot create password-protected PDFs Basic graphics: No gradients, patterns, or complex paths Text extraction: May not work perfectly on all PDFs (depends on PDF structure) Related Skills pptx-generator: For creating PowerPoint presentations docx-generator: For creating Word documents xlsx-generator: For creating Excel spreadsheets