React Native Image Resizer

A React Native module that can create scaled versions of local images (also supports the assets library on iOS).

Setup

Install the package with rnpm:

npm install rnpm -g
rnpm install react-native-image-resizer

Note: on latest versions of React Native, you may have an error during the Gradle build on Android (com.android.dex.DexException: Multiple dex files define Landroid/support/v7/appcompat/R$anim). Run cd android && ./gradlew clean to fix this.

Usage example

import ImageResizer from 'react-native-image-resizer';

ImageResizer.createResizedImage(imageUri, newWidth, newHeight, compressFormat, quality, rotation, outputPath).then((resizedImageUri) => {
  // resizeImageUri is the URI of the new image that can now be displayed, uploaded...
}).catch((err) => {
  // Oops, something went wrong. Check that the filename is correct and
  // inspect err to get more details.
});

Sample app

A basic, sample app is available in the example folder. It uses the module to resize a photo from the Camera Roll.

API

promise createResizedImage(path, maxWidth, maxHeight, compressFormat, quality, rotation = 0, outputPath)

The promise resolves with a string containing the uri of the new file.

Option	Description
path	Path of image
maxWidth	Image max width (ratio is preserved)
maxHeight	Image max height (ratio is preserved)
compressFormat	Can be either JPEG, PNG (android only) or WEBP (android only).
quality	A number between 0 and 100. Used for the JPEG compression.
rotation	Rotation to apply to the image, in degrees, for android only. On iOS, the resizing is done such that the orientation is always up.
outputPath	The resized image path. If null, resized image will be stored in cache folder. To set outputPath make sure to add option for rotation too (if no rotation is needed, just set it to 0).

Other open-source modules by the folks at BAM

• rn-camera-roll
• react-native-animated-picker
• cordova-plugin-native-routing