@toolsmithhq/imagecore-native

Native C/C++ image processing for React Native via JSI. Synchronous, zero-copy, MIT-licensed.

Part of ImageCore. For the easier file-based API, see @toolsmithhq/imagecore-files.

Quick Start (recommended)

Most apps should use @toolsmithhq/imagecore-files — a high-level wrapper that handles file I/O and memory management for you:

npm install @toolsmithhq/imagecore-native @toolsmithhq/imagecore-files

import {
  convertFile, resizeFile, cropFile, rotateFile, flipFile,
  compressFile, losslessJpegRotate, getFileImageInfo,
  readFileExif, stripFileExif,
} from '@toolsmithhq/imagecore-files';

// Convert HEIC to JPEG
const jpegUri = await convertFile(sourceUri, 'jpeg', 0.85);         // default quality: 0.85

// Resize
const thumbUri = await resizeFile(sourceUri, 200, 200, 'jpeg');     // default quality: 0.95

// Crop
const croppedUri = await cropFile(sourceUri, 100, 50, 400, 300, 'jpeg');

// Rotate
const rotatedUri = await rotateFile(sourceUri, 90, 'jpeg');         // 90, 180, or 270

// Flip
const mirroredUri = await flipFile(sourceUri, true, false, 'png');  // horizontal flip

// Compress
const compressedUri = await compressFile(sourceUri, 0.5, 'jpeg');

// Lossless JPEG rotate (zero quality loss — rearranges DCT blocks directly)
const losslessUri = await losslessJpegRotate(sourceUri, 90);

// Image info
const info = await getFileImageInfo(sourceUri);
// { width: 4032, height: 3024, format: 'jpeg', hasExif: true, fileSize: 2048576 }

// EXIF metadata
const exif = await readFileExif(sourceUri);
// { Make: 'Apple', Model: 'iPhone 15', DateTime: '2024:01:15 10:30:00', ... }

// Strip EXIF (binary removal for JPEG — no re-encoding)
const strippedUri = await stripFileExif(sourceUri);

File in, file out. No ArrayBuffers, no manual memory management.

Install (low-level only)

npm install @toolsmithhq/imagecore-native

Features

• Format conversion — JPEG, PNG, WebP, BMP, TIFF, HEIC, AVIF
• Lossless JPEG — rotate, crop, EXIF strip (zero quality loss)
• Pixel operations — resize (Lanczos/bilinear/nearest), crop, rotate, flip
• EXIF metadata — read and strip
• Synchronous JSI — all operations run on the JS thread via C++ (no async bridge)
• Platform HEIC — iOS ImageIO + Android HeifWriter (no LGPL dependencies)

Usage

All methods are synchronous and operate on ArrayBuffers. DecodedImage objects must be freed when done.

import { ImageCore } from '@toolsmithhq/imagecore-native';

// Convert format
const pngBuffer = ImageCore.convert(inputBuffer, { format: 'png', quality: 0.9 });

// Lossless JPEG rotate (zero quality loss)
const rotated = ImageCore.jpegLosslessRotate(jpegBuffer, 90);

// Decode → resize → encode
const decoded = ImageCore.decode(inputBuffer);
const resized = ImageCore.resize(decoded, { width: 800, height: 600, filter: 'lanczos' });
const output = ImageCore.encode(resized, { format: 'webp', quality: 0.85 });
resized.free();
decoded.free();

// EXIF
const exif = ImageCore.readExif(jpegBuffer);
const stripped = ImageCore.stripExif(jpegBuffer);

API

| Method | Description | |---|---| | getImageInfo(data) | Get dimensions, format, EXIF presence without full decode | | decode(data) | Decode any format to RGBA pixels | | encode(image, opts) | Encode pixels to any format | | convert(data, opts) | Decode + encode in one call | | jpegLosslessRotate(data, 90\|180\|270) | Lossless JPEG rotate via DCT block rearrangement | | jpegLosslessCrop(data, region) | Lossless JPEG crop at MCU boundaries | | jpegStripExif(data) | Binary EXIF removal from JPEG | | resize(image, opts) | Resize with Lanczos, bilinear, or nearest filter | | crop(image, region) | Crop to { x, y, width, height } | | rotate(image, 90\|180\|270) | Rotate decoded image | | flipHorizontal(image) | Mirror horizontally | | flipVertical(image) | Flip vertically | | readExif(data) | Read EXIF metadata tags | | stripExif(data) | Strip metadata from any format |

Memory Management

decode(), resize(), crop(), rotate(), flipHorizontal(), and flipVertical() return DecodedImage objects that hold native memory. Always call .free() when done.

If you don't want to manage memory manually, use @toolsmithhq/imagecore-files instead.

License

MIT