A React Native module that can create scaled versions of local images (also supports the assets library on iOS).
First, install the package:
npm install react-native-image-resizer --save
Use rnpm:
npm install rnpm -g
rnpm link
You need to add RNImageResizer.xcodeproj
to Libraries and add libRNImageResizer.a
to Link Binary With Libraries under Build Phases. More info and screenshots about how to do this is available in the React Native documentation.
For react-native >= v0.15, this command will do it automatically:
react-native link react-native-image-resizer
For react-native = v0.14 You will have to update them manually:
In android/settings.gradle
, add:
include ':react-native-image-resizer'
project(':react-native-image-resizer').projectDir = new File(settingsDir, '../node_modules/react-native-image-resizer/android')
In android/app/build.gradle
add:
dependencies {
...
compile project(':react-native-image-resizer')
}
package com.example;
import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import com.facebook.react.LifecycleState;
import com.facebook.react.ReactInstanceManager;
import com.facebook.react.ReactRootView;
import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
import com.facebook.react.shell.MainReactPackage;
import com.facebook.soloader.SoLoader;
// IMPORT HERE
import fr.bamlab.rnimageresizer.ImageResizerPackage;
// ---
public class MainActivity extends Activity implements DefaultHardwareBackBtnHandler {
private ReactInstanceManager mReactInstanceManager;
private ReactRootView mReactRootView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mReactRootView = new ReactRootView(this);
mReactInstanceManager = ReactInstanceManager.builder()
.setApplication(getApplication())
.setBundleAssetName("index.android.bundle")
.setJSMainModuleName("index.android")
.addPackage(new MainReactPackage())
// REGISTER PACKAGE HERE
.addPackage(new ImageResizerPackage())
// ---
.setUseDeveloperSupport(BuildConfig.DEBUG)
.setInitialLifecycleState(LifecycleState.RESUMED)
.build();
mReactRootView.startReactApplication(mReactInstanceManager, "example", null);
setContentView(mReactRootView);
}
...
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.
});
A basic, sample app is available in the example
folder. It uses the module to resize a photo from the Camera Roll.
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). |