Optimized Image Viewer: High Performance React Native & Reanimated

react-native-reanimated-viewer

A high performance image viewer in react-native created from react-native-reanimated.

Install

npm install react-native-reanimated-viewer react-native-reanimated react-native-gesture-handler --save
cd ios & pod install

Then you need follow the extra steps to finish the installation: react-native-reanimated & react-native-gesture-handler.

Example

example

import React, { memo, useRef, useMemo } from 'react';
import { View, Image } from 'react-native';
import { ImageWrapper, ImageViewer } from 'react-native-reanimated-viewer';
const ImageViewerPage = () => {
  const imageRef = useRef(null);
  const mockData = useMemo(
    () => [
      {
        smallUrl:
          'https://img2.baidu.com/it/u=1835117106,152654887&fm=253&fmt=auto&app=138&f=JPEG?w=500&h=556',
        url: 'https://img2.baidu.com/it/u=1835117106,152654887&fm=253&fmt=auto&app=138&f=JPEG?w=500&h=556',
      },
      {
        smallUrl:
          'https://img1.baidu.com/it/u=139191814,3489949748&fm=253&fmt=auto&app=138&f=JPEG?w=491&h=491',
        url: 'https://img1.baidu.com/it/u=139191814,3489949748&fm=253&fmt=auto&app=138&f=JPEG?w=491&h=491',
      },
      {
        smallUrl:
          'https://img0.baidu.com/it/u=2926715223,1445444764&fm=253&fmt=auto&app=120&f=JPEG?w=500&h=500',
        url: 'https://img0.baidu.com/it/u=2926715223,1445444764&fm=253&fmt=auto&app=120&f=JPEG?w=500&h=500',
      },
    ],
    [],
  );
  return (
    <>
      <ImageViewer
        ref={imageRef}
        data={mockData.map((el) => ({ key: `key-${el.url}`, source: { uri: el.url } }))}
      />
      <View style={{ flexDirection: 'row' }}>
        {mockData.map((el, index) => (
          <ImageWrapper
            key={el.smallUrl}
            viewerRef={imageRef}
            index={index}
            source={{
              uri: el.smallUrl,
            }}
          >
            <Image
              source={{
                uri: el.smallUrl,
              }}
              style={{ width: 100, height: 100 }}
            />
          </ImageWrapper>
        ))}
      </View>
    </>
  );
};
export default memo(ImageViewerPage);

Notice

You need to wrap your image components used by ImageWrapper in this package.

Props

ImageViewer

name	required	type	default	description	Example
data	true	`{key: string; source: ImageURISource}[]`	undefined	The original source & key of image	`[{key: 'image-1', source: {uri:'http://*./**.png'}}]`
renderCustomComponent	false	`(_: {item: {key: string; source: ImageURISource}; index: number;}) => ReactElement`	undefined	The custom Element in ImageViewer	`({index}) => <Text>current index is {index}</Text>`
onLongPress	false	`(_: {item: {key: string; source: ImageURISource}; index: number;}) => void`	undefined	Once you pressed image viewer for a long time, the function will active	({index}) => console.log(`${index} pressed long`)
imageResizeMode	false	`ImageResizeMode`	undefined	The resizeMode props of image in viewer	`"contain"`
onChange	false	`(currentIndex: number) => void`	undefined	When the viewer finished swiping, the function will be called	(currentIndex) => console.log(`current index is ${currentIndex}`)
dragUpToCloseEnabled	false	`boolean`	undefined	Enable dragging up to close the viewer	`true`
maxScale	false	`number`	3	Image maximum magnification	`3`
doubleTapScale	false	`number`	2	The magnification when double-clicking the image	`2`
shouldCloseViewer	false	`(_: {gesture: GestureEnum; index: number; imageData: ImageViewerItemData; loaded: boolean; }) => boolean`	undefined	Control whether the viewer can be closed under certain gestures	`({gesture}) => gesture === GestureEnum.Tap`

ImageWrapper

name	required	type	default	description	Example
viewerRef	true	`MutableRefObject<ImageViewerRef>`	undefined	The ref of imageViewer	`[{url:'http://*./**.png'}]`
index	true	`number`	undefined	The index of current ImageWrapper	`({index}) => <Text>current index is {index}</Text>`
source	true	`ImageURISource`	undefined	The inner component image's url	`{uri: 'https://*./**.png'}`
style	false	`ViewStyle`	undefined	The style of image wrapper	`{margin: 10}`
onPress	false	`() => boolean or undefined`	undefined	Once you pressed image, the function will active.(If it returns false, the viewer will not show.)	`() => console.log('pressed')`
viewProps	false	`ViewProps`	undefined	You can custom the container props	`{onLongPress: () => console.warn('longPressed')}`