import React, {useState} from 'react' import {ActivityIndicator, StyleSheet} from 'react-native' import { Gesture, GestureDetector, PanGesture, } from 'react-native-gesture-handler' import Animated, { runOnJS, SharedValue, useAnimatedReaction, useAnimatedRef, useAnimatedStyle, useSharedValue, withSpring, } from 'react-native-reanimated' import {Image} from 'expo-image' import type { Dimensions as ImageDimensions, ImageSource, Transform, } from '../../@types' import { applyRounding, createTransform, prependPan, prependPinch, prependTransform, readTransform, TransformMatrix, } from '../../transforms' const MIN_SCREEN_ZOOM = 2 const MAX_ORIGINAL_IMAGE_ZOOM = 2 const initialTransform = createTransform() type Props = { imageSrc: ImageSource onRequestClose: () => void onTap: () => void onZoom: (isZoomed: boolean) => void isScrollViewBeingDragged: boolean showControls: boolean measureSafeArea: () => { x: number y: number width: number height: number } imageAspect: number | undefined imageDimensions: ImageDimensions | undefined dismissSwipePan: PanGesture transforms: Readonly< SharedValue<{ scaleAndMoveTransform: Transform cropFrameTransform: Transform cropContentTransform: Transform isResting: boolean isHidden: boolean }> > } const ImageItem = ({ imageSrc, onTap, onZoom, isScrollViewBeingDragged, measureSafeArea, imageAspect, imageDimensions, dismissSwipePan, transforms, }: Props) => { const [isScaled, setIsScaled] = useState(false) const committedTransform = useSharedValue(initialTransform) const panTranslation = useSharedValue({x: 0, y: 0}) const pinchOrigin = useSharedValue({x: 0, y: 0}) const pinchScale = useSharedValue(1) const pinchTranslation = useSharedValue({x: 0, y: 0}) const containerRef = useAnimatedRef() // Keep track of when we're entering or leaving scaled rendering. // Note: DO NOT move any logic reading animated values outside this function. useAnimatedReaction( () => { if (pinchScale.value !== 1) { // We're currently pinching. return true } const [, , committedScale] = readTransform(committedTransform.value) if (committedScale !== 1) { // We started from a pinched in state. return true } // We're at rest. return false }, (nextIsScaled, prevIsScaled) => { if (nextIsScaled !== prevIsScaled) { runOnJS(handleZoom)(nextIsScaled) } }, ) function handleZoom(nextIsScaled: boolean) { setIsScaled(nextIsScaled) onZoom(nextIsScaled) } // On Android, stock apps prevent going "out of bounds" on pan or pinch. You should "bump" into edges. // If the user tried to pan too hard, this function will provide the negative panning to stay in bounds. function getExtraTranslationToStayInBounds( candidateTransform: TransformMatrix, screenSize: {width: number; height: number}, ) { 'worklet' if (!imageAspect) { return [0, 0] } const [nextTranslateX, nextTranslateY, nextScale] = readTransform(candidateTransform) const scaledDimensions = getScaledDimensions( imageAspect, nextScale, screenSize, ) const clampedTranslateX = clampTranslation( nextTranslateX, scaledDimensions.width, screenSize.width, ) const clampedTranslateY = clampTranslation( nextTranslateY, scaledDimensions.height, screenSize.height, ) const dx = clampedTranslateX - nextTranslateX const dy = clampedTranslateY - nextTranslateY return [dx, dy] } const pinch = Gesture.Pinch() .onStart(e => { 'worklet' const screenSize = measureSafeArea() pinchOrigin.value = { x: e.focalX - screenSize.width / 2, y: e.focalY - screenSize.height / 2, } }) .onChange(e => { 'worklet' const screenSize = measureSafeArea() if (!imageDimensions) { return } // Don't let the picture zoom in so close that it gets blurry. // Also, like in stock Android apps, don't let the user zoom out further than 1:1. const [, , committedScale] = readTransform(committedTransform.value) const maxCommittedScale = Math.max( MIN_SCREEN_ZOOM, (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM, ) const minPinchScale = 1 / committedScale const maxPinchScale = maxCommittedScale / committedScale const nextPinchScale = Math.min( Math.max(minPinchScale, e.scale), maxPinchScale, ) pinchScale.value = nextPinchScale // Zooming out close to the corner could push us out of bounds, which we don't want on Android. // Calculate where we'll end up so we know how much to translate back to stay in bounds. const t = createTransform() prependPan(t, panTranslation.value) prependPinch(t, nextPinchScale, pinchOrigin.value, pinchTranslation.value) prependTransform(t, committedTransform.value) const [dx, dy] = getExtraTranslationToStayInBounds(t, screenSize) if (dx !== 0 || dy !== 0) { pinchTranslation.value = { x: pinchTranslation.value.x + dx, y: pinchTranslation.value.y + dy, } } }) .onEnd(() => { 'worklet' // Commit just the pinch. let t = createTransform() prependPinch( t, pinchScale.value, pinchOrigin.value, pinchTranslation.value, ) prependTransform(t, committedTransform.value) applyRounding(t) committedTransform.value = t // Reset just the pinch. pinchScale.value = 1 pinchOrigin.value = {x: 0, y: 0} pinchTranslation.value = {x: 0, y: 0} }) const pan = Gesture.Pan() .averageTouches(true) // Unlike .enabled(isScaled), this ensures that an initial pinch can turn into a pan midway: .minPointers(isScaled ? 1 : 2) .onChange(e => { 'worklet' const screenSize = measureSafeArea() if (!imageDimensions) { return } const nextPanTranslation = {x: e.translationX, y: e.translationY} let t = createTransform() prependPan(t, nextPanTranslation) prependPinch( t, pinchScale.value, pinchOrigin.value, pinchTranslation.value, ) prependTransform(t, committedTransform.value) // Prevent panning from going out of bounds. const [dx, dy] = getExtraTranslationToStayInBounds(t, screenSize) nextPanTranslation.x += dx nextPanTranslation.y += dy panTranslation.value = nextPanTranslation }) .onEnd(() => { 'worklet' // Commit just the pan. let t = createTransform() prependPan(t, panTranslation.value) prependTransform(t, committedTransform.value) applyRounding(t) committedTransform.value = t // Reset just the pan. panTranslation.value = {x: 0, y: 0} }) const singleTap = Gesture.Tap().onEnd(() => { 'worklet' runOnJS(onTap)() }) const doubleTap = Gesture.Tap() .numberOfTaps(2) .onEnd(e => { 'worklet' const screenSize = measureSafeArea() if (!imageDimensions || !imageAspect) { return } const [, , committedScale] = readTransform(committedTransform.value) if (committedScale !== 1) { // Go back to 1:1 using the identity vector. let t = createTransform() committedTransform.value = withClampedSpring(t) return } // Try to zoom in so that we get rid of the black bars (whatever the orientation was). const screenAspect = screenSize.width / screenSize.height const candidateScale = Math.max( imageAspect / screenAspect, screenAspect / imageAspect, MIN_SCREEN_ZOOM, ) // But don't zoom in so close that the picture gets blurry. const maxScale = Math.max( MIN_SCREEN_ZOOM, (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM, ) const scale = Math.min(candidateScale, maxScale) // Calculate where we would be if the user pinched into the double tapped point. // We won't use this transform directly because it may go out of bounds. const candidateTransform = createTransform() const origin = { x: e.absoluteX - screenSize.width / 2, y: e.absoluteY - screenSize.height / 2, } prependPinch(candidateTransform, scale, origin, {x: 0, y: 0}) // Now we know how much we went out of bounds, so we can shoot correctly. const [dx, dy] = getExtraTranslationToStayInBounds( candidateTransform, screenSize, ) const finalTransform = createTransform() prependPinch(finalTransform, scale, origin, {x: dx, y: dy}) committedTransform.value = withClampedSpring(finalTransform) }) const composedGesture = isScrollViewBeingDragged ? // If the parent is not at rest, provide a no-op gesture. Gesture.Manual() : Gesture.Exclusive( dismissSwipePan, Gesture.Simultaneous(pinch, pan), doubleTap, singleTap, ) const containerStyle = useAnimatedStyle(() => { const {scaleAndMoveTransform, isHidden} = transforms.value // Apply the active adjustments on top of the committed transform before the gestures. // This is matrix multiplication, so operations are applied in the reverse order. let t = createTransform() prependPan(t, panTranslation.value) prependPinch(t, pinchScale.value, pinchOrigin.value, pinchTranslation.value) prependTransform(t, committedTransform.value) const [translateX, translateY, scale] = readTransform(t) const manipulationTransform = [ {translateX}, {translateY: translateY}, {scale}, ] const screenSize = measureSafeArea() return { opacity: isHidden ? 0 : 1, transform: scaleAndMoveTransform.concat(manipulationTransform), width: screenSize.width, maxHeight: screenSize.height, aspectRatio: imageAspect, alignSelf: 'center', } }) const imageCropStyle = useAnimatedStyle(() => { const {cropFrameTransform} = transforms.value return { flex: 1, overflow: 'hidden', transform: cropFrameTransform, } }) const imageStyle = useAnimatedStyle(() => { const {cropContentTransform} = transforms.value return { flex: 1, transform: cropContentTransform, } }) const [showLoader, setShowLoader] = useState(false) const [hasLoaded, setHasLoaded] = useState(false) useAnimatedReaction( () => { return transforms.value.isResting && !hasLoaded }, (show, prevShow) => { if (show && !prevShow) { runOnJS(setShowLoader)(false) } else if (!prevShow && show) { runOnJS(setShowLoader)(true) } }, ) const type = imageSrc.type const borderRadius = type === 'circle-avi' ? 1e5 : type === 'rect-avi' ? 20 : 0 return ( {showLoader && ( )} setHasLoaded(false)} style={{flex: 1, borderRadius}} accessibilityHint="" accessibilityIgnoresInvertColors cachePolicy="memory" /> ) } const styles = StyleSheet.create({ container: { height: '100%', overflow: 'hidden', justifyContent: 'center', }, loading: { position: 'absolute', left: 0, right: 0, top: 0, bottom: 0, justifyContent: 'center', }, }) function getScaledDimensions( imageAspect: number, scale: number, screenSize: {width: number; height: number}, ): ImageDimensions { 'worklet' const screenAspect = screenSize.width / screenSize.height const isLandscape = imageAspect > screenAspect if (isLandscape) { return { width: scale * screenSize.width, height: (scale * screenSize.width) / imageAspect, } } else { return { width: scale * screenSize.height * imageAspect, height: scale * screenSize.height, } } } function clampTranslation( value: number, scaledSize: number, screenSize: number, ): number { 'worklet' // Figure out how much the user should be allowed to pan, and constrain the translation. const panDistance = Math.max(0, (scaledSize - screenSize) / 2) const clampedValue = Math.min(Math.max(-panDistance, value), panDistance) return clampedValue } function withClampedSpring(value: any) { 'worklet' return withSpring(value, {overshootClamping: true}) } export default React.memo(ImageItem)