pdf-to-tiff-pure-aloka

Pure Node.js PDF to TIFF converter — zero system dependencies, zero native bindings.
Uses pdfjs-dist (Mozilla) + pureimage + custom TIFF encoder. Works on any OS without installing Ghostscript, Poppler, or ImageMagick.

Table of Contents

• Features
• Requirements
• Installation
• Quick Start
• API Reference
  • convertPdfToTiff()
  • convertPdfToTiffHighFidelity()
  • ConversionOptions
  • ConversionResult
  • convertPdfToText()
• Examples
• Compression Modes
• Known Limitations
• License

Features

• ✅ 100% pure JavaScript / TypeScript — no C++ bindings, no native add-ons
• ✅ No system dependencies — no Ghostscript, Poppler, or ImageMagick required
• ✅ Three compression modes — LZW, PackBits, or uncompressed
• ✅ Barcode-safe binarization — Otsu adaptive threshold → crisp 1-bit black-and-white output
• ✅ TypeScript types included — full .d.ts declarations shipped
• ✅ One TIFF per PDF page — page-1.tiff, page-2.tiff, …
• ✅ PDF text extraction — extract all text from a PDF as a plain string
• ✅ MIT License — free for commercial and open-source use

Requirements

| Requirement | Version | |-------------|---------| | Node.js | ≥ 18.0.0 | | npm | ≥ 8.0.0 |

No system libraries needed.

Installation

npm install pdf-to-tiff-pure-aloka

Quick Start

const { convertPdfToTiff, convertPdfToText } = require('pdf-to-tiff-pure-aloka');

async function main() {
  // Convert to TIFF
  const result = await convertPdfToTiff('document.pdf', './output');

  if (result.success) {
    console.log(`Converted ${result.convertedPages} pages:`);
    result.outputFiles.forEach(f => console.log(' -', f));
  } else {
    console.error('Conversion failed:', result.error);
  }

  // Extract text
  const text = await convertPdfToText('document.pdf');
  console.log(text);
}

main();

TypeScript:

import { convertPdfToTiff, convertPdfToText, ConversionOptions } from 'pdf-to-tiff-pure-aloka';

const options: ConversionOptions = {
  scale: 2.0,
  compression: 'lzw',
  filePrefix: 'scan',
};

const result = await convertPdfToTiff('document.pdf', './output', options);
console.log(result.outputFiles);
// Multi-page: → ['./output/scan-1.tiff', './output/scan-2.tiff', ...]
// Single-page: → ['./output/scan.tiff']

API Reference

convertPdfToTiff()

convertPdfToTiff(
  pdfPath: string,
  outputDir: string,
  options?: ConversionOptions
): Promise<ConversionResult>

Converts every page of a PDF file into individual TIFF files.

| Parameter | Type | Required | Description | |------------|---------------------|----------|-------------| | pdfPath | string | ✅ Yes | Path to the source PDF file (absolute or relative) | | outputDir| string | ✅ Yes | Directory where TIFF files are written. Created automatically if it does not exist. | | options | ConversionOptions | No | Optional settings (see below) |

Throws Error if:

• The PDF file does not exist or cannot be read
• The PDF is corrupt or has no pages
• scale is outside the valid range (0 < scale ≤ 10)
• The output directory cannot be created

convertPdfToTiffHighFidelity()

convertPdfToTiffHighFidelity(
  pdfPath: string,
  outputDir: string,
  options?: ConversionOptions
): Promise<ConversionResult>

Converts every page of a PDF file into individual TIFF files using node-canvas (Cairo rendering backend) for high-fidelity output.

Unlike the standard convertPdfToTiff() which uses pureimage, this function leverages the Cairo graphics library via node-canvas to achieve full Canvas 2D API support. This ensures embedded images, barcodes, QR codes, and complex vector graphics are rendered accurately in the output TIFF.

Use this when:

• Your PDFs contain embedded images that must be preserved
• Barcodes and QR codes need pixel-perfect fidelity
• Complex vector graphics or gradients need accurate rendering
• You need better font rendering for international text

Note: This function requires node-canvas to be installed. It may have system dependencies depending on your operating system (Cairo, pixman).

| Parameter | Type | Required | Description | |------------|---------------------|----------|-------------| | pdfPath | string | ✅ Yes | Path to the source PDF file (absolute or relative) | | outputDir| string | ✅ Yes | Directory where TIFF files are written. Created automatically if it does not exist. | | options | ConversionOptions | No | Optional settings (see below) |

Throws Error if:

• node-canvas is not installed
• The PDF file does not exist or cannot be read
• The PDF is corrupt or has no pages
• scale is outside the valid range (0 < scale ≤ 10)
• The output directory cannot be created

ConversionOptions

interface ConversionOptions {
  scale?: number;             // Default: 3.0
  compression?: TiffCompression; // Default: 'lzw'
  filePrefix?: string;        // Default: 'page'
  binarize?: boolean;         // Default: false
}

type TiffCompression = 'none' | 'packbits' | 'lzw';

| Option | Type | Default | Description | |---------------|-------------------|------------|-------------| | scale | number | 3.0 | Render scale multiplier. 1.0 = 72 DPI (PDF native), 2.0 = 144 DPI, 3.0 ≈ 216 DPI (default), 4.17 ≈ 300 DPI. Valid range: (0, 10]. | | compression | TiffCompression | 'lzw' | TIFF compression algorithm. See Compression Modes. | | filePrefix | string | 'page' | Output filename prefix. Single-page PDFs: files are named ${prefix}.tiff (no page number). Multi-page PDFs: files are named ${prefix}-${pageNumber}.tiff. | | binarize | boolean | false | When true, converts each page to 1-bit black-and-white using Otsu's adaptive threshold before encoding. Eliminates the anti-aliased gray fringe that pureimage adds to barcode edges, making barcodes scannable by hardware readers and fax systems. Output IFD: BitsPerSample=1, PhotometricInterpretation=0 (WhiteIsZero). |

ConversionResult

interface ConversionResult {
  success: boolean;       // true if ALL pages converted successfully
  totalPages: number;     // total pages in the PDF
  convertedPages: number; // pages that were successfully written
  outputFiles: string[];  // absolute paths to each TIFF file, in page order
  error?: string;         // set if success is false
}

Examples

Convert with custom DPI (~300 DPI)

const { convertPdfToTiff } = require('pdf-to-tiff-pure-aloka');

const result = await convertPdfToTiff('invoice.pdf', './tiff-output', {
  scale: 4.17,        // 4.17 × 72 DPI ≈ 300 DPI
  compression: 'lzw',
  filePrefix: 'invoice',
});
// Multi-page: → invoice-1.tiff, invoice-2.tiff, ...
// Single-page: → invoice.tiff

Output to current directory

const { convertPdfToTiff } = require('pdf-to-tiff-pure-aloka');

const result = await convertPdfToTiff('document.pdf', './', {
  filePrefix: 'scan',
});

console.log(result.outputFiles);
// Single-page: → ['scan.tiff']
// Multi-page:  → ['scan-1.tiff', 'scan-2.tiff', ...]

Uncompressed output (fastest, largest files)

const result = await convertPdfToTiff('scan.pdf', './raw', {
  compression: 'none',
});

PackBits compression (fast, moderate size)

const result = await convertPdfToTiff('report.pdf', './compressed', {
  compression: 'packbits',
});

High-fidelity conversion with embedded images (node-canvas)

Use convertPdfToTiffHighFidelity() when your PDFs contain embedded images, complex graphics, or need pixel-perfect rendering:

const { convertPdfToTiffHighFidelity } = require('pdf-to-tiff-pure-aloka');

const result = await convertPdfToTiffHighFidelity('document-with-images.pdf', './output', {
  scale: 3.0,
  compression: 'lzw',
  filePrefix: 'page',
});

TypeScript:

import { convertPdfToTiffHighFidelity } from 'pdf-to-tiff-pure-aloka';

const result = await convertPdfToTiffHighFidelity('catalog.pdf', './output', {
  scale: 4.17,  // ~300 DPI for high quality
  compression: 'lzw',
});

Barcode / fax-quality output (1-bit black-and-white)

Use binarize: true when the PDF contains barcodes, QR codes, or must be sent to a fax system. The canvas renderer anti-aliases barcode edges, producing gray pixels that can confuse fixed-threshold hardware readers. Enabling binarization applies Otsu's adaptive threshold to remove all gray, writing a compact 1-bit TIFF instead of an 8-bit RGB one.

const { convertPdfToTiff } = require('pdf-to-tiff-pure-aloka');

const result = await convertPdfToTiff('barcode-invoice.pdf', './output', {
  scale: 3.0,          // higher scale = more barcode detail
  compression: 'lzw',
  binarize: true,      // → 1-bit B&W TIFF, Otsu adaptive threshold
});

TypeScript:

import { convertPdfToTiff, ConversionOptions } from 'pdf-to-tiff-pure-aloka';

const options: ConversionOptions = {
  scale: 3.0,
  compression: 'lzw',
  binarize: true,
};

const result = await convertPdfToTiff('barcode.pdf', './output', options);
// Output TIFF: BitsPerSample=1, PhotometricInterpretation=0 (WhiteIsZero)

Tip: For documents that mix barcodes with full-colour content (logos, photos), leave binarize: false (default) and use a separate post-processing step for the pages that need scanning.

Error handling

const { convertPdfToTiff } = require('pdf-to-tiff-pure-aloka');

try {
  const result = await convertPdfToTiff('document.pdf', './output');

  if (!result.success) {
    // Some pages failed (non-fatal per-page errors)
    console.warn(`Warning: ${result.error}`);
    console.log(`Converted ${result.convertedPages}/${result.totalPages} pages`);
  }

  result.outputFiles.forEach(file => {
    console.log('Created:', file);
  });

} catch (err) {
  // Fatal error: file not found, corrupt PDF, invalid options
  console.error('Fatal error:', err.message);
}

Check output file sizes

const fs = require('fs');
const { convertPdfToTiff } = require('pdf-to-tiff-pure-aloka');

const result = await convertPdfToTiff('document.pdf', './output', {
  compression: 'lzw',
});

result.outputFiles.forEach(file => {
  const size = fs.statSync(file).size;
  console.log(`${file} — ${(size / 1024).toFixed(1)} KB`);
});

Extract text from a PDF

const { convertPdfToText } = require('pdf-to-tiff-pure-aloka');

const text = await convertPdfToText('document.pdf');
console.log(text);
// Output: full text of all pages, pages separated by \n\n

TypeScript:

import { convertPdfToText } from 'pdf-to-tiff-pure-aloka';

const text: string = await convertPdfToText('invoice.pdf');
if (text.trim().length > 0) {
  console.log('Extracted text:', text);
} else {
  console.log('No text found (image-only or encrypted PDF)');
}

Compression Modes

| Mode | TIFF Tag | File Size | Encoding Speed | Best For | |------------|----------|---------------|----------------|----------| | none | 1 | Largest | Fastest | Debugging, further processing | | packbits | 32773 | Moderate | Fast | General purpose | | lzw | 5 | Smallest | Moderate | Storage, archival (default) |

Tip: For text-heavy or white-space-heavy documents, LZW achieves the best compression ratio. For photos or complex vector art, the difference between modes is smaller.

convertPdfToText()

convertPdfToText(pdfPath: string): Promise<string>

Extracts all text content from a PDF file and returns it as a plain string.

| Parameter | Type | Required | Description | |-----------|----------|----------|-------------| | pdfPath | string | ✅ Yes | Path to the source PDF file (absolute or relative) |

Returns a Promise<string> — concatenated text of all pages, with pages separated by \n\n.

Returns an empty string if the PDF contains no extractable text (image-only or rasterized content).

Throws Error if:

• The PDF file does not exist or cannot be read
• The PDF is corrupt or has no pages

Note: Text extraction works on PDFs with embedded text streams. Scanned PDFs (images only) will return an empty string — use convertPdfToTiff to get image output and apply OCR separately if needed.

Known Limitations

| Limitation | Details | |------------|---------| | Performance | Rendering is 3–10× slower than system-library solutions (Ghostscript, Poppler) because everything runs in JavaScript. Expect ~1–5 seconds per page depending on complexity. | | Font rendering | PDFs that use unembedded proprietary fonts (e.g. old Vietnamese TCVN3 fonts) may render as empty boxes. Standard fonts (Helvetica, Times, Courier) require the standardFontDataUrl option of pdfjs-dist; this package uses best-effort fallback only. | | Color accuracy | Complex color spaces (CMYK, ICC profiles) are handled by pdfjs on a best-effort basis. Slight color shifts are possible. | | Memory usage | Very high-resolution renders (scale > 4.0) of large pages can use significant RAM. Process pages sequentially for large documents. | | No multi-page TIFF | Each page produces a separate .tiff file. Multi-page (strips) TIFF is not supported. || Binarize on mixed pages | binarize: true applies a single global Otsu threshold to the whole page. Pages with both full-colour photos and barcodes may lose colour detail. Use binarize: false (default) for colour output. |

License

MIT © pdf-to-tiff-pure-aloka contributors