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/React Native

Image

A React component for displaying different types of images, including network images, static resources, temporary local images, and images from local disk, such as the camera roll.

This example shows both fetching and displaying an image from local storage as well as one from network.

import React, { Component } from 'react';
import { AppRegistry, View, Image } from 'react-native';

export default class DisplayAnImage extends Component {
  render() {
    return (
      <View>
        <Image
          source={require('./img/favicon.png')}
        />
        <Image
          style={{width: 50, height: 50}}
          source={{uri: 'https://facebook.github.io/react/img/logo_og.png'}}
        />
      </View>
    );
  }
}

// skip this line if using Create React Native App
AppRegistry.registerComponent('DisplayAnImage', () => DisplayAnImage);

You can also add style to an image:

import React, { Component } from 'react';
import { AppRegistry, View, Image, StyleSheet } from 'react-native';

const styles = StyleSheet.create({
  stretch: {
    width: 50,
    height: 200
  }
});

export default class DisplayAnImageWithStyle extends Component {
  render() {
    return (
      <View>
        <Image
          style={styles.stretch}
          source={require('./img/favicon.png')}
        />
      </View>
    );
  }
}

// skip these lines if using Create React Native App
AppRegistry.registerComponent(
  'DisplayAnImageWithStyle',
  () => DisplayAnImageWithStyle
);

GIF and WebP support on Android

When building your own native code, GIF and WebP are not supported by default on Android.

You will need to add some optional modules in android/app/build.gradle, depending on the needs of your app.

dependencies {
  // If your app supports Android versions before Ice Cream Sandwich (API level 14)
  compile 'com.facebook.fresco:animated-base-support:1.0.1'

  // For animated GIF support
  compile 'com.facebook.fresco:animated-gif:1.0.1'

  // For WebP support, including animated WebP
  compile 'com.facebook.fresco:animated-webp:1.0.1'
  compile 'com.facebook.fresco:webpsupport:1.0.1'

  // For WebP support, without animations
  compile 'com.facebook.fresco:webpsupport:1.0.1'
}

Also, if you use GIF with ProGuard, you will need to add this rule in proguard-rules.pro :

-keep class com.facebook.imagepipeline.animated.factory.AnimatedFactoryImpl {
  public AnimatedFactoryImpl(com.facebook.imagepipeline.bitmaps.PlatformBitmapFactory, com.facebook.imagepipeline.core.ExecutorSupplier);
}

Props

blurRadius?: number

blurRadius: the blur radius of the blur filter added to the image

onError?: function

Invoked on load error with {nativeEvent: {error}}.

onLayout?: function

Invoked on mount and layout changes with {nativeEvent: {layout: {x, y, width, height}}}.

onLoad?: function

Invoked when load completes successfully.

onLoadEnd?: function

Invoked when load either succeeds or fails.

onLoadStart?: function

Invoked on load start.

e.g., onLoadStart={(e) => this.setState({loading: true})}

resizeMode?: enum('cover', 'contain', 'stretch', 'repeat', 'center')

Determines how to resize the image when the frame doesn't match the raw image dimensions.

  • cover: 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).

  • 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).

  • stretch: Scale width and height independently, This may change the aspect ratio of the src.

  • repeat: Repeat the image to cover the frame of the view. The image will keep it's size and aspect ratio. (iOS only)

source?: ImageSourcePropType

The image source (either a remote URL or a local file resource).

This prop can also contain several remote URLs, specified together with their width and height and potentially with scale/other URI arguments. The native side will then choose the best uri to display based on the measured size of the image container. A cache property can be added to control how networked request interacts with the local cache.

The currently supported formats are png, jpg, jpeg, bmp, gif, webp (Android only), psd (iOS only).

style?: style

Layout Props...
Shadow Props...
Transforms...
backfaceVisibility enum('visible', 'hidden')
backgroundColor color
borderBottomLeftRadius number
borderBottomRightRadius number
borderColor color
borderRadius number
borderTopLeftRadius number
borderTopRightRadius number
borderWidth number
opacity number
overflow enum('visible', 'hidden')
resizeMode Object.keys(ImageResizeMode)
tintColor color

Changes the color of all the non-transparent pixels to the tintColor.

androidoverlayColor string

When the image has rounded corners, specifying an overlayColor will cause the remaining space in the corners to be filled with a solid color. This is useful in cases which are not supported by the Android implementation of rounded corners: - Certain resize modes, such as 'contain' - Animated GIFs

A typical way to use this prop is with images displayed on a solid background and setting the overlayColor to the same color as the background.

For details of how this works under the hood, see http://frescolib.org/docs/rounded-corners-and-circles.html

ImageResizeMode is an Enum for different image resizing modes, set via the resizeMode style property on Image components. The values are contain, cover, stretch, center, repeat.

testID?: string

A unique identifier for this element to be used in UI Automation testing scripts.

androidresizeMethod?: enum('auto', 'resize', 'scale')

The mechanism that should be used to resize the image when the image's dimensions differ from the image view's dimensions. Defaults to auto.

  • auto: Use heuristics to pick between resize and scale.

  • resize: A software operation which changes the encoded image in memory before it gets decoded. This should be used instead of scale when the image is much larger than the view.

  • scale: The image gets drawn downscaled or upscaled. Compared to resize, scale is faster (usually hardware accelerated) and produces higher quality images. This should be used if the image is smaller than the view. It should also be used if the image is slightly bigger than the view.

More details about resize and scale can be found at http://frescolib.org/docs/resizing-rotating.html.

iosaccessibilityLabel?: node

The text that's read by the screen reader when the user interacts with the image.

iosaccessible?: bool

When true, indicates the image is an accessibility element.

ioscapInsets?: {top: number, left: number, bottom: number, right: number}

When the image is resized, the corners of the size specified by capInsets will stay a fixed size, but the center content and borders of the image will be stretched. This is useful for creating resizable rounded buttons, shadows, and other resizable assets. More info in the official Apple documentation.

iosdefaultSource?: {uri: string, width: number, height: number, scale: number}, number

A static image to display while loading the image source.

  • uri - a string representing the resource identifier for the image, which should be either a local file path or the name of a static image resource (which should be wrapped in the require('./path/to/image.png') function).
  • width, height - can be specified if known at build time, in which case these will be used to set the default <Image/> component dimensions.
  • scale - used to indicate the scale factor of the image. Defaults to 1.0 if unspecified, meaning that one image pixel equates to one display point / DIP.
  • number - Opaque type returned by something like require('./image.jpg').

iosonPartialLoad?: function

Invoked when a partial load of the image is complete. The definition of what constitutes a "partial load" is loader specific though this is meant for progressive JPEG loads.

iosonProgress?: function

Invoked on download progress with {nativeEvent: {loaded, total}}.

Methods

static getSize(uri: string, success: function, failure?: function):

Retrieve the width and height (in pixels) of an image prior to displaying it. This method can fail if the image cannot be found, or fails to download.

In order to retrieve the image dimensions, the image may first need to be loaded or downloaded, after which it will be cached. This means that in principle you could use this method to preload images, however it is not optimized for that purpose, and may in future be implemented in a way that does not fully load/download the image data. A proper, supported way to preload images will be provided as a separate API.

Does not work for static image resources.

Parameters:
Name and Type Description
uri

string

The location of the image.

success

function

The function that will be called if the image was successfully found and width and height retrieved.

[failure]

function

The function that will be called if there was an error, such as failing to to retrieve the image.

static prefetch(url: string):

Prefetches a remote image for later use by downloading it to the disk cache

Parameters:
Name and Type Description
url

string

The remote location of the image.

© 2015–2017 Facebook Inc.
Licensed under the Creative Commons Attribution 4.0 International Public License.
https://facebook.github.io/react-native/docs/image.html