deca-image-tools

A lightweight TypeScript library for image processing operations, offering a variety of filters, transformations including edge detection, blur effects, color manipulation, and image transformations.

Installation

npm install deca-image-tools

Features

• Edge detection using Sobel operators
• Gaussian blur filter
• Image sharpening
• Brightness adjustment
• Image colorization
• Color inversion
• Image rotation
• Image skewing
• Image file saving
• TypeScript support out of the box
• Zero dependencies
• Fully typed API

Usage

Edge Detection

The edgeDetect function applies Sobel edge detection to an image, converting it to grayscale and highlighting edges:

import { edgeDetect } from 'deca-image-tools';

// Assuming you have an ImageData object from a canvas
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);

// Apply edge detection
const edgedImage = edgeDetect(imageData);

// Draw the result back to canvas
ctx.putImageData(edgedImage, 0, 0);

Gaussian Blur

The gaussianBlur function applies a Gaussian blur effect to smooth the image:

import { gaussianBlur } from 'deca-image-tools';

// Apply Gaussian blur with default radius
const blurredImage = gaussianBlur(imageData);

// Or specify a custom radius
const customBlurredImage = gaussianBlur(imageData, 2);

Color Manipulation

The library provides several color manipulation functions:

import { colorize, invertColors, adjustBrightness } from 'deca-image-tools';

// Apply a red tint
const color = { r: 255, g: 0, b: 0 };
const colorizedImage = colorize(imageData, color);

// Invert colors
const invertedImage = invertColors(imageData);

// Adjust brightness (factor > 1 brightens, < 1 darkens)
const brightenedImage = adjustBrightness(imageData, 1.5);

Image Transformations

The library includes functions for geometric transformations:

import { rotateImage, skewImage } from 'deca-image-tools';

// Rotate image by 45 degrees
const rotatedImage = rotateImage(imageData, 45);

// Skew image horizontally and vertically
const skewedImage = skewImage(imageData, 0.2, 0.1);

Saving Images

The library provides functionality to save processed images:

import { saveImage } from 'deca-image-tools';

// Save the processed image to a file
await saveImage(imageData, 'output.png');

API Reference

edgeDetect(imageData: ImageData): ImageData

Detects edges in an image using the Sobel operator.

Parameters:

• imageData: ImageData object containing the source image

Returns:

• New ImageData object containing the edge-detected image

gaussianBlur(imageData: ImageData, radius?: number): ImageData

Applies a Gaussian blur effect to the image.

Parameters:

• imageData: ImageData object containing the source image
• radius: Optional blur radius (default: 1)

Returns:

• New ImageData object containing the blurred image

sharpen(imageData: ImageData): ImageData

Applies a sharpening filter to the image.

Parameters:

• imageData: ImageData object containing the source image

Returns:

• New ImageData object containing the sharpened image

adjustBrightness(imageData: ImageData, factor: number): ImageData

Adjusts the brightness of an image.

Parameters:

• imageData: ImageData object containing the source image
• factor: Brightness adjustment factor (>1 brightens, <1 darkens)

Returns:

• New ImageData object with adjusted brightness

colorize(imageData: ImageData, color: { r: number; g: number; b: number }): ImageData

Applies a color tint to an image.

Parameters:

• imageData: ImageData object containing the source image
• color: Object containing RGB values (0-255) for the tint color

Returns:

• New ImageData object containing the colorized image

invertColors(imageData: ImageData): ImageData

Inverts the colors of an image.

Parameters:

• imageData: ImageData object containing the source image

Returns:

• New ImageData object with inverted colors

rotateImage(imageData: ImageData, degrees: number): ImageData

Rotates an image by the specified angle.

Parameters:

• imageData: ImageData object containing the source image
• degrees: Rotation angle in degrees

Returns:

• New ImageData object containing the rotated image

skewImage(imageData: ImageData, skewX: number, skewY: number): ImageData

Applies horizontal and vertical skewing to an image.

Parameters:

• imageData: ImageData object containing the source image
• skewX: Horizontal skew factor
• skewY: Vertical skew factor

Returns:

• New ImageData object containing the skewed image

saveImage(imageData: ImageData, filePath: string): Promise

Saves an image to a file.

Parameters:

• imageData: ImageData object to save
• filePath: Path where the image should be saved

Returns:

• Promise that resolves when the image has been saved

Technical Details

• The edge detection algorithm uses Sobel operators for gradient calculation
• Gaussian blur uses a 3x3 kernel with customizable radius
• Sharpening uses a 3x3 kernel matrix
• Rotation uses bilinear interpolation for smooth results
• All operations create new ImageData objects, leaving the original unchanged
• Alpha channel is preserved in all operations
• Image saving requires Node.js environment with 'canvas' package

Project Structure

deca-image-tools/
├── src/
│   └── index.ts          # Main source code
├── dist/                 # Compiled output
│   ├── index.js
│   └── index.d.ts
├── package.json          # Package configuration
├── tsconfig.json         # TypeScript configuration
└── README.md            # Documentation

Development

Setup

1. Clone the repository:

git clone https://github.com/yourusername/deca-image-tools.git
cd deca-image-tools

2. Install dependencies:

npm install

Available Scripts

• npm run build - Compiles the TypeScript code
• npm test - Runs the test suite
• npm run lint - Runs ESLint for code quality
• npm run format - Formats code using Prettier

Requirements

• Modern browser with Canvas API support
• TypeScript 4.0+ (for TypeScript users)
• Node.js 14+ (for development)
• Node.js canvas package (for image saving functionality)

Browser Support

The package supports all modern browsers that implement the Canvas API:

• Chrome 60+
• Firefox 55+
• Safari 11+
• Edge 79+

Performance Considerations

• Image processing operations are performed on the CPU and may be computationally intensive for large images
• Consider downscaling large images before processing
• All operations are synchronous and will block the main thread
• The Gaussian blur and rotation operations may be particularly intensive on large images
• Transformation operations may cause some quality loss due to interpolation

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Please make sure to:

• Update tests as appropriate
• Follow the existing code style
• Update documentation for any new features

License

MIT

Author

Tom Tarpey (decagondev)

Changelog

1.0.2

• Added image rotation support
• Added image skewing support
• Added image saving functionality
• Performance improvements for transformation operations

1.0.1

• Gaussian blur filter
• Image sharpening
• Brightness adjustment
• Color inversion support

1.0.0

• Initial release
• Edge detection implementation
• Image colorization

Acknowledgments

• This package implements several fundamental image processing algorithms including the Sobel edge detection algorithm, Gaussian blur, and various geometric transformations

Support

For support, please open an issue in the GitHub repository or contact the maintainers.