react-native-color-matrix-image-filters

Various color matrix based image filters for iOS & Android.

Status

• iOS & Android:
  • filter components work as stackable wrappers for Image, ImageBackground and react-native-fast-image components
• react-native:
  • supported versions: ">=0.56.0"

Installation

pod 'React', :path => '../node_modules/react-native'
pod 'RNColorMatrixImageFilters', :path => '../node_modules/react-native-color-matrix-image-filters'

Scope

This module is meant to be used for simple stuff, like "grayscaling inactive user avatar" etc. Check react-native-image-filter-kit if you need some advanced features like image blending/composing, extracting filtering results to file system and ability to create custom filters.

Example

import { Image } from 'react-native'
import {
  Grayscale,
  Sepia,
  Tint,
  ColorMatrix,
  concatColorMatrices,
  invert,
  contrast,
  saturate
} from 'react-native-color-matrix-image-filters'

const GrayscaledImage = (imageProps) => (
  <Grayscale>
    <Image {...imageProps} />
  </Grayscale>
)

const CombinedFiltersImage = (imageProps) => (
  <Tint amount={1.25}>
    <Sepia>
      <Image {...imageProps} />
    </Sepia>
  </Tint>
)

const ColorMatrixImage = (imageProps) => (
  <ColorMatrix
    matrix={concatColorMatrices([saturate(-0.9), contrast(5.2), invert()])}
    // alt: matrix={[saturate(-0.9), contrast(5.2), invert()]}
  >
    <Image {...imageProps} />
  </ColorMatrix>
)

Original	Grayscaled

CombinedFilters	ColorMatrix

Usage

Each filter support all of View props. Also some filters have optional amount prop which takes a number. ColorMatrix filter has matrix prop which takes a Matrix - an array of 20 numbers. Additionally library exports functions like grayscale, tint etc. - these functions return values of Matrix type and their results can be combined with concatColorMatrices function. If you need to combine several filters, consider using ColorMatrix with concatColorMatrices - generally it is more performant than corresponding stack of filter components.

Reference

Supported filters

Functions

• concatColorMatrices(matrices: Matrix[]): Matrix

Matrix type

• A 4x5 matrix for color transformations represented by array - consult Android docs for more specific info about it's format

Misc

• You may check MatrixFilterConstructor example app to play with filters
• This library was tested only with standard Image component, but in theory it should work with any image that conforms to CMIFImageView protocol or is based on Android ImageView class
• Installing react-native-fast-image is not required - this module doesn't depend on it

Credits

• parrot image by Robert01
• most of color filters are taken from color-matrix project by @skratchdot, Pixi.js sources and Webkit sources
• concatColorMatrices function is based on Android SDK sources
• DuoTone filter based on example by José Manuel Pérez