iq-scm / react-native-responsive-image

Responsive image component for React Native

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

1. Modify any files in ./src directory

2. Propagate changes by cp -R ./src ./ResponsiveImageExample/src