React Native Responsive Image
Why?
React Native's Image size is rendered with the same dimensions regardless of device screen size and screen resolution. That's bad. This component scales itself seemlesly on all iOS and Android devices.
Installation
npm install react-native-responsive-image --save
Usage
<ResponsiveImage>
is expecting initWidth
and initHeight
props.
These values are used to set image size on any device that has screen size iPhone Plus, or larger. Image is then scaled down for any smaller device.
Optional prop component
is used to pass down either an Image
or ImageBackground
imported react-native (defaults to Image
if not provided)
Example
import React, { Component } from "react";
import { AppRegistry, StyleSheet, View } from "react-native";
import ResponsiveImage from "react-native-responsive-image";
class App extends Component {
render() {
return (
<View
style={{
flexGrow: 1,
justifyContent: "center",
alignItems: "center",
flexDirection: "row"
}}
>
<ResponsiveImage
source={{ uri: "https://reactjs.org/logo-og.png" }}
initWidth="138"
initHeight="138"
/>
<ResponsiveImage
source={{ uri: "https://reactjs.org/logo-og.png" }}
initWidth="138"
initHeight="138"
/>
<ResponsiveImage
source={{ uri: "https://reactjs.org/logo-og.png" }}
initWidth="138"
initHeight="138"
/>
</View>
);
}
}
AppRegistry.registerComponent("ResponsiveImageExample", () => App);
For initWidth=138
it looks like this:
Device | Screen width | Scale | <Image> width |
---|---|---|---|
iPhone SE | 320 | 0.77 | 106 |
iPhone X | 375 | 0.902 | 117 |
iPhone8 Plus | 414 | 1 | 138 |
Nokia 5 | 360 | 0.87 | 120 |
iPad (or any tablet) | - | 1 | 138 |
Just one image?
It sounds like you could save some loading by delivering low resolution images to screens with lower resolution. The best way is to serve just one high-resolution (retina) well compressed image. It’s surprising how well they can be compressed, and the result looks the same.
Example project
Create project
expo init ResponsiveImageExample
- go with 'expo-template-blank'
cp ./example/App.js ./ResponsiveImageExample/App.js
cp -R ./src ./ResponsiveImageExample
cd ResponsiveImageExample
yarn start
Development
-
Modify any files in ./src directory
-
Propagate changes by
cp -R ./src ./ResponsiveImageExample/src