Sudoku Generator

A simple and flexible Sudoku generator that can create puzzles of different sizes and difficulty levels, with PDF export functionality.

Installation

npm install @amanwebdev/sudoku-generator

Usage

Basic Sudoku Generation

const { generateSudoku } = require('@amanwebdev/sudoku-generator');

// Generate a 9x9 Sudoku with easy difficulty
const sudoku = generateSudoku(9, 'easy');

console.log('Puzzle:');
console.log(sudoku.grid);

console.log('Solution:');
console.log(sudoku.solution);

PDF Export

const { generateSudoku, toPDF } = require('@amanwebdev/sudoku-generator');
const fs = require('fs');

const sudoku = generateSudoku(9, 'easy');

// Generate puzzle PDF
const puzzlePdf = await toPDF(sudoku.grid, {
  title: 'Sudoku Puzzle #1',
  theme: 'light'
});
fs.writeFileSync('puzzle.pdf', puzzlePdf);

// Generate solution PDF with visual distinction
const solutionPdf = await toPDF(sudoku.grid, {
  title: 'Sudoku Solution #1',
  theme: 'light',
  showSolution: true
}, sudoku.solution);
fs.writeFileSync('solution.pdf', solutionPdf);

Image Export

const { generateSudoku, toImage } = require('@amanwebdev/sudoku-generator');
const fs = require('fs');

const sudoku = generateSudoku(9, 'medium');

// Generate puzzle image
const puzzleImage = toImage(sudoku.grid, {
  theme: 'light',
  cellSize: 80,
  format: 'png'
});
fs.writeFileSync('puzzle.png', puzzleImage);

// Generate solution image with visual distinction
const solutionImage = toImage(sudoku.grid, {
  theme: 'dark',
  cellSize: 60,
  format: 'jpeg',
  quality: 0.9,
  showSolution: true
}, sudoku.solution);
fs.writeFileSync('solution.jpg', solutionImage);

API

generateSudoku(size, difficulty)

Generates a new Sudoku puzzle.

Parameters:

• size: The size of the Sudoku grid. Can be 4, 6, or 9.
• difficulty: The difficulty of the puzzle. Can be 'easy', 'medium', or 'hard'.

Returns: A Sudoku object with the following properties:

• size: The size of the Sudoku grid.
• grid: A 2D array representing the puzzle (0 = empty cell).
• solution: A 2D array representing the complete solution.
• difficulty: The difficulty level used.

toPDF(grid, options?, solution?)

Exports a Sudoku grid to PDF format.

Parameters:

• grid: A 2D number array representing the puzzle grid
• options: Optional PDF configuration object
• solution: Optional 2D number array for solution display (required when showSolution: true)

Options:

• theme: 'light' | 'dark' | custom theme object (default: 'light')
• title: PDF title text (default: 'Sudoku Puzzle')
• author: PDF author metadata (default: 'Sudoku Generator')
• subject: PDF subject metadata (default: 'Sudoku Puzzle')
• keywords: PDF keywords metadata (default: 'sudoku, puzzle, game')
• showSolution: Boolean to display solution with visual distinction (default: false)

Custom Theme:

{
  background: '#ffffff',
  gridColor: '#000000', 
  textColor: '#000000',
  boxLineColor: '#000000'
}

Returns: Promise<Uint8Array> - PDF file as bytes

toImage(grid, options?, solution?)

Exports a Sudoku grid to image format (PNG or JPEG).

Parameters:

• grid: A 2D number array representing the puzzle grid
• options: Optional image configuration object
• solution: Optional 2D number array for solution display (required when showSolution: true)

Options:

• theme: 'light' | 'dark' | custom theme object (default: 'light')
• cellSize: Size of each cell in pixels (default: 60)
• showSolution: Boolean to display solution with visual distinction (default: false)
• format: 'png' | 'jpeg' - Output image format (default: 'png')
• quality: JPEG quality from 0 to 1 (default: 0.95, only applies to JPEG format)

Returns: Buffer - Image file as bytes

Sample Output

Puzzle PDF

Clean, printable Sudoku puzzles with professional formatting:

Solution PDF

Solutions with visual distinction between given and solved digits:

Features

PDF Export

• A4 Portrait Layout: Professional 210×297mm format
• Multiple Grid Sizes: Optimized layouts for 4×4, 6×6, and 9×9 grids
• Theme Support: Light, dark, and custom color themes
• Solution Display: Visual distinction between given and solved digits
• Metadata Support: Title, author, subject, and keywords
• Print Ready: Proper stroke weights and sizing for printing

Image Export

• Flexible Canvas Size: Configurable cell sizes for different output resolutions
• Multiple Formats: PNG and JPEG export with quality control
• Theme Support: Same theming system as PDF export
• Solution Overlay: Visual distinction between given and solved digits
• Server-side Rendering: Node.js canvas-based generation
• Scalable Output: Adjustable dimensions for web, print, or display use

Visual Design

• Given digits: Bold, full opacity
• Solution digits: Normal weight, lighter color for clear distinction
• Responsive sizing: Cell sizes adjust based on grid size
• Clean typography: Centered numbers with proper spacing