App.js

import React, { Component } from 'react'
import { AppRegistry, Animated, Easing, View, StyleSheet, Image, Dimensions, ScrollView, TouchableOpacity, Text } from 'react-native'

const deviceWidth = Dimensions.get('window').width
const deviceHeight = Dimensions.get('window').height
const DISMISS_MODAL_THRESHOLD = 150 //distance we have to scroll in the y direction to dismiss the carousel

// const images = [
//   'https://s-media-cache-ak0.pinimg.com/originals/ee/51/39/ee5139157407967591081ee04723259a.png',
//   'https://s-media-cache-ak0.pinimg.com/originals/40/4f/83/404f83e93175630e77bc29b3fe727cbe.jpg',
//   'https://s-media-cache-ak0.pinimg.com/originals/8d/1a/da/8d1adab145a2d606c85e339873b9bb0e.jpg',
// ]

const images = [
  require('./assets/images/image01.jpg'),
  require('./assets/images/image02.jpg'),
  require('./assets/images/image03.jpg'),
]

class ZoomView extends Component {

  static defaultProps = {
    doAnimateZoomReset: false,
    maximumZoomScale: 2,
    minimumZoomScale: 1,
    zoomed: false,
    zoomEnabled: false,
    zoomHeight: 219,
    zoomWidth: deviceWidth,
  }

  state = {
    startY: null, //y position of touch when we start scrolling on zoom view 
  }

  componentDidUpdate(prevProps) {
    if (prevProps.zoomed === true && this.props.zoomed === false) { //make sure we are scrolled to top
      this.handleResetZoomScale()
    }
  }

  setZoomRef = node => {
    if (node) {

      this.zoomRef = node
      this.scrollResponderRef = this.zoomRef.getScrollResponder()

      this.scrollResponderRef.scrollResponderHandleTouchStart = (event) => {
        const isZoom = event.nativeEvent.touches.length > 1 ? true : false

        if (!this.props.zoomed) {
          this.setState({ startY: event.nativeEvent.locationY })
        }

        if (isZoom) {
          if (!this.props.zoomed) {
            this.props.onZoomed()
          }
        }
      }

      this.scrollResponderRef.scrollResponderHandleTouchEnd = (event) => {
        console.log('end')
        if (this.props.zoomed) {
          this.imageRef.measure((ox, oy, width, height, px, py) => {
            if (width <= this.props.zoomWidth) {
              //this.props.onZoomClosePress() //MH TODO: go back to isolated carousel
              this.props.onZoomExit()
              return
            }
            else {
              return
            }
          })
        }
        else {
          const isZoom = event.nativeEvent.touches.length > 1 ? true : false

          if (!isZoom) {
            const currentY = event.nativeEvent.locationY
            const scrollYDistance = Math.abs(this.state.startY - currentY)
            //if we have swiped further up or down than the threshold distance and we're not zooming on an image, dismiss the isolated carousel mode
            if (scrollYDistance > DISMISS_MODAL_THRESHOLD) {
              this.props.onZoomClosePress()
            }
          }
        }
      }
    }
  }

  setImageRef = node => {
    if (node) {
      this.imageRef = node
    }
  }

  handleZoomViewPress = () => {
    if (!this.props.zoomEnabled) {
      this.props.onZoomEnabled()
    }
    else {
      if (this.props.zoomed) {
        this.handleResetZoomScale()
        this.props.onZoomClosePress()
      }
    }
  }

  handleResetZoomScale = () => {
    this.scrollResponderRef.scrollResponderZoomTo({ x: 0, y: 0, width: this.props.zoomWidth, height: this.props.zoomHeight, animated: true })
  }

  render() {
    return (
      <ScrollView
        contentContainerStyle={{ alignItems: 'center', justifyContent: 'center', }}
        centerContent //centers content when zoom is less than scroll view bounds 
        maximumZoomScale={this.props.zoomEnabled ? this.props.maximumZoomScale : 1} //setting to 1 disallows zoom
        minimumZoomScale={this.props.minimumZoomScale}
        showsHorizontalScrollIndicator={false}
        showsVerticalScrollIndicator={false}
        ref={this.setZoomRef}
        scrollEnabled={this.props.zoomEnabled} //prevents you from panning on image
        scrollEventThrottle={10}
        style={{
          overflow: 'visible',
        }}
      >
        <TouchableOpacity
          onPress={this.handleZoomViewPress}
          flexGrow={1}
          flex={1}
        >
          <Image
            source={this.props.source}
            //flexGrow={1}
            width={deviceWidth}
            aspectRatio={1.716}
            ref={this.setImageRef}
          />
        </TouchableOpacity>
      </ScrollView>
    )
  }
}

AppRegistry.registerComponent('ZoomView', () => ZoomView);


export default class App extends Component {

  //ZOOM VIEW
  animZoomVal = new Animated.Value(0)

  animInverseZoomVal = this.animZoomVal.interpolate({
    inputRange: [0, 1],
    outputRange: [1, 0],
  })

  animValUpTiming = Animated.timing(this.animZoomVal, {
    toValue: 1,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })
  animValDownTiming = Animated.timing(this.animZoomVal, {
    toValue: 0,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })
  animTranslateY = this.animZoomVal.interpolate({
    inputRange: [0, 1],
    outputRange: [0, 175],
  })

  //SCROLLBAR
  animScrollBarOpacityVal = new Animated.Value(1)
  animScrollOpacityUpTiming = Animated.timing(this.animScrollBarOpacityVal, {
    toValue: 1,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })
  animScrollOpacityDownTiming = Animated.timing(this.animScrollBarOpacityVal, {
    toValue: 0,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })

  //CLOSE BUTTON
  animCloseOpacityVal = new Animated.Value(0)
  animCloseOpacityUpTiming = Animated.timing(this.animCloseOpacityVal, {
    toValue: 1,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })
  animCloseOpacityDownTiming = Animated.timing(this.animCloseOpacityVal, {
    toValue: 0,
    duraton: 300,
    easing: Easing.inOut(Easing.quad),
  })

  animScrollXVal = new Animated.Value(0)

  // To get clamp to work on the right edge we have to clamp using the indicator's left position
  scrollXVal = this.animScrollXVal.interpolate({
    inputRange: [0, deviceWidth * (images.length - 1)],
    outputRange: [0, (deviceWidth / images.length) * (images.length - 1)],
    extrapolate: 'clamp',
  })

  state = {
    zoomEnabled: false,
    zoomed: false,
  }

  handleZoomEnabled = () => {
    this.setState({ zoomEnabled: true })
    this.animValUpTiming.start()
    this.animCloseOpacityUpTiming.start()
  }

  handleZoomed = () => {
    this.setState({ zoomed: true })
    this.animScrollOpacityDownTiming.start()
    this.animCloseOpacityDownTiming.start()
  }

  handleZoomClosePress = () => {
    if (this.state.zoomEnabled) {
      this.animScrollOpacityUpTiming.start()
      this.setState({ zoomEnabled: false, zoomed: false })
      this.animValDownTiming.start()
      this.animCloseOpacityDownTiming.start()
    }
  }

  handleZoomExit = () => {
    if (this.state.zoomed) {
      this.setState({ zoomed: false, zoomEnabled: true })
      this.animScrollOpacityUpTiming.start()
      this.animCloseOpacityUpTiming.start()
    }
  }

  renderZoomView = (image, i) => {
    return (
      <ZoomView
        key={i}
        source={image}
        zoomEnabled={this.state.zoomEnabled}
        zoomed={this.state.zoomed}
        onZoomEnabled={this.handleZoomEnabled}
        onZoomClosePress={this.handleZoomClosePress}
        onZoomExit={this.handleZoomExit}
        onZoomed={this.handleZoomed}
        translateY={this.animTranslateY}
        index={i}
      />
    )
  }

  render() {

    return (
      <View
        style={{
          flex: 1,
          flexGrow: 1,
          alignItems: 'center',
          justifyContent: 'flex-start',
          marginTop: 40,
        }}
      >
        <Animated.View
          style={{
            opacity: this.animInverseZoomVal,
            paddingBottom: 20,
          }}
        >
          <Text
            style={{
              fontSize: 18,
            }}
          >
            Title
          </Text>
        </Animated.View>
        <Animated.View
          style={{
            transform: [
              { translateY: this.animTranslateY },
            ],
            height: 219,
            zIndex: 10,
          }}
        >
          <Animated.ScrollView
            grow
            horizontal
            pagingEnabled
            showsHorizontalScrollIndicator={false}
            scrollEventThrottle={10}
            onScroll={Animated.event(
              [{ nativeEvent: { contentOffset: { x: this.animScrollXVal } } }]
            )}
            scrollEnabled={!this.state.zoomed}
            style={{
              overflow: 'visible',
            }}
          >
            {
              images.map((image, i) => {
                return (this.renderZoomView(image, i))
              })
            }
          </Animated.ScrollView>
          <Animated.View
            style={{
              width: deviceWidth,
              height: 5,
            }}
          >

            <Animated.View
              style={{
                backgroundColor: '#E5E5E5',
                opacity: this.animScrollBarOpacityVal,
              }}
            >
              <Animated.View
                style={{
                  backgroundColor: '#111111',
                  width: deviceWidth / images.length,
                  height: 5,
                  transform: [
                    {
                      translateX: this.scrollXVal,
                    },
                  ]
                }}
              />
            </Animated.View>
          </Animated.View>
        </Animated.View>
        <Animated.View
          style={{
            opacity: this.animInverseZoomVal,
            marginTop: 50,
            alignSelf: 'flex-start',
            paddingLeft: 20,
            paddingRight: 20,
          }}
        >
          <Text
            style={{
              marginBottom: 20,
              fontSize: 16,
              backgroundColor: 'transparent'
            }}
          >
            Subtitle
          </Text>
          <Text
            style={{
              backgroundColor: 'transparent'
            }}
          >
            Aliquam in velit in ligula gravida cursus at ut lacus. Vestibulum luctus eleifend lorem, et tincidunt mi. Nam semper turpis in dolor sollicitudin elementum. Maecenas ornare felis ultricies congue maximus. Proin id luctus eros, nec varius libero. Integer at tincidunt augue. Aenean non ex dignissim, lacinia nibh id, convallis odio. Quisque consequat blandit elit eu pulvinar. Pellentesque hendrerit rhoncus magna, feugiat accumsan metus gravida sed. Integer ut mollis felis. Ut elementum nisi a libero imperdiet, eget volutpat ex sagittis. Morbi eu placerat nisi, et bibendum sapien.
          </Text>
        </Animated.View>
        {
          this.state.zoomEnabled &&
          (
            <Animated.View
              style={{
                position: 'absolute',
                top: 20,
                right: 20,
                opacity: this.animCloseOpacityVal,
              }}
            >
              <TouchableOpacity
                onPress={this.handleZoomClosePress}
                hitSlop={{ top: 20, left: 20, right: 20, bottom: 20 }}
              >
                <Image
                  source={require('./assets/images/close.png')}
                />
              </TouchableOpacity>
            </Animated.View>
          )
        }
      </View>

    )
  }
}

AppRegistry.registerComponent('App', () => App);