Performant React Native image component.
React Native's Image component handles image caching like browsers
for the most part.
If the server is returning proper cache control
headers for images you'll generally get the sort of built in
caching behavior you'd have in a browser.
Even so many people have noticed:
- Flickering.
- Cache misses.
- Low performance loading from cache.
- Low performance in general.
FastImage is an Image replacement that solves these issues.
FastImage is a wrapper around
SDWebImage (iOS)
and
Glide (Android).
Features
- Aggressively cache images.
- Add authorization headers.
- Prioritize images.
- Preload images.
- GIF support.
- Border radius.
Usage
Note: You must be using React Native 0.60.0 or higher to use the most recent version of react-native-fast-image.
yarn add react-native-fast-image
import FastImage from 'react-native-fast-image'
const YourImage = () => (
<FastImage
style={{ width: 200, height: 200 }}
source={{
uri: 'https://unsplash.it/400/400?image=1',
headers: { Authorization: 'someAuthToken' },
priority: FastImage.priority.normal,
}}
resizeMode={FastImage.resizeMode.contain}
/>
)
Are you using Glide already using an AppGlideModule?
- Are you using Glide already using an AppGlideModule? (you might have problems if you don't read this)
Are you using Proguard?
If you use Proguard you will need to add these lines to android/app/proguard-rules.pro:
-keep public class com.dylanvann.fastimage.* {*;}
-keep public class com.dylanvann.fastimage.** {*;}
-keep public class * implements com.bumptech.glide.module.GlideModule
-keep public class * extends com.bumptech.glide.module.AppGlideModule
-keep public enum com.bumptech.glide.load.ImageHeaderParser$** {
**[] $VALUES;
public *;
}
Properties
source?: object
Source for the remote image to load.
source.uri?: string
Remote url to load the image from. e.g. 'https://facebook.github.io/react/img/logo_og.png'.
source.headers?: object
Headers to load the image with. e.g. { Authorization: 'someAuthToken' }.
source.priority?: enum
FastImage.priority.low- Low Priority.FastImage.priority.normal(Default) - Normal Priority.FastImage.priority.high- High Priority.
source.cache?: enum
FastImage.cacheControl.immutable- (Default) - Only updates if url changes.FastImage.cacheControl.web- Use headers and follow normal caching procedures.FastImage.cacheControl.cacheOnly- Only show images from cache, do not make any network requests.
resizeMode?: enum
FastImage.resizeMode.contain- Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or less than the corresponding dimension of the view (minus padding).FastImage.resizeMode.cover(Default) - Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or larger than the corresponding dimension of the view (minus padding).FastImage.resizeMode.stretch- Scale width and height independently, This may change the aspect ratio of the src.FastImage.resizeMode.center- Do not scale the image, keep centered.
onLoadStart?: () => void
Called when the image starts to load.
onProgress?: (event) => void
Called when the image is loading.
e.g. onProgress={e => console.log(e.nativeEvent.loaded / e.nativeEvent.total)}
onLoad?: (event) => void
Called on a successful image fetch. Called with the width and height of the loaded image.
e.g. onLoad={e => console.log(e.nativeEvent.width, e.nativeEvent.height)}
onError?: () => void
Called on an image fetching error.
onLoadEnd?: () => void
Called when the image finishes loading, whether it was successful or an error.
style
A React Native style. Supports using borderRadius.
fallback: boolean
If true will fallback to using Image.
In this case the image will still be styled and laid out the same way as FastImage.
tintColor?: number, string
If supplied, changes the color of all the non-transparent pixels to the given color.
Static Methods
FastImage.preload: (source[]) => void
Preload images to display later. e.g.
FastImage.preload([
{
uri: 'https://facebook.github.io/react/img/logo_og.png',
headers: { Authorization: 'someAuthToken' },
},
{
uri: 'https://facebook.github.io/react/img/logo_og.png',
headers: { Authorization: 'someAuthToken' },
},
])
Troubleshooting
If you have any problems using this library try the steps in troubleshooting and see if they fix it.
Development
Follow these instructions to get the example app running.
Supported React Native Versions
This project only aims to support the latest version of React Native.
This simplifies the development and the testing of the project.
If you require new features or bug fixes for older versions you can fork this project.
Credits
The idea for this modules came from
vovkasm's
react-native-web-image
package.
It also uses Glide and SDWebImage, but didn't have some features I needed (priority, headers).
Thanks to @mobinni for helping with the conceptualization