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