import React from 'react'; import PropTypes from 'prop-types'; import IconButton from 'mastodon/components/icon_button'; import { defineMessages, injectIntl } from 'react-intl'; const messages = defineMessages({ compress: { id: 'lightbox.compress', defaultMessage: 'Compress image view box' }, expand: { id: 'lightbox.expand', defaultMessage: 'Expand image view box' }, }); const MIN_SCALE = 1; const MAX_SCALE = 4; const NAV_BAR_HEIGHT = 66; const getMidpoint = (p1, p2) => ({ x: (p1.clientX + p2.clientX) / 2, y: (p1.clientY + p2.clientY) / 2, }); const getDistance = (p1, p2) => Math.sqrt(Math.pow(p1.clientX - p2.clientX, 2) + Math.pow(p1.clientY - p2.clientY, 2)); const clamp = (min, max, value) => Math.min(max, Math.max(min, value)); // Normalizing mousewheel speed across browsers // copy from: https://github.com/facebookarchive/fixed-data-table/blob/master/src/vendor_upstream/dom/normalizeWheel.js const normalizeWheel = event => { // Reasonable defaults const PIXEL_STEP = 10; const LINE_HEIGHT = 40; const PAGE_HEIGHT = 800; let sX = 0, sY = 0, // spinX, spinY pX = 0, pY = 0; // pixelX, pixelY // Legacy if ('detail' in event) { sY = event.detail; } if ('wheelDelta' in event) { sY = -event.wheelDelta / 120; } if ('wheelDeltaY' in event) { sY = -event.wheelDeltaY / 120; } if ('wheelDeltaX' in event) { sX = -event.wheelDeltaX / 120; } // side scrolling on FF with DOMMouseScroll if ('axis' in event && event.axis === event.HORIZONTAL_AXIS) { sX = sY; sY = 0; } pX = sX * PIXEL_STEP; pY = sY * PIXEL_STEP; if ('deltaY' in event) { pY = event.deltaY; } if ('deltaX' in event) { pX = event.deltaX; } if ((pX || pY) && event.deltaMode) { if (event.deltaMode === 1) { // delta in LINE units pX *= LINE_HEIGHT; pY *= LINE_HEIGHT; } else { // delta in PAGE units pX *= PAGE_HEIGHT; pY *= PAGE_HEIGHT; } } // Fall-back if spin cannot be determined if (pX && !sX) { sX = (pX < 1) ? -1 : 1; } if (pY && !sY) { sY = (pY < 1) ? -1 : 1; } return { spinX: sX, spinY: sY, pixelX: pX, pixelY: pY, }; }; export default @injectIntl class ZoomableImage extends React.PureComponent { static propTypes = { alt: PropTypes.string, src: PropTypes.string.isRequired, width: PropTypes.number, height: PropTypes.number, onClick: PropTypes.func, zoomButtonHidden: PropTypes.bool, intl: PropTypes.object.isRequired, } static defaultProps = { alt: '', width: null, height: null, }; state = { scale: MIN_SCALE, zoomMatrix: { type: null, // 'full-width' 'full-height' rate: null, // full screen scale rate clientWidth: null, clientHeight: null, offsetWidth: null, offsetHeight: null, clientHeightFixed: null, scrollTop: null, scrollLeft: null, }, zoomState: 'expand', // 'expand' 'compress' navigationHidden: false, dragPosition: { top: 0, left: 0, x: 0, y: 0 }, dragged: false, lockScroll: { x: 0, y: 0 }, } removers = []; container = null; image = null; lastTouchEndTime = 0; lastDistance = 0; componentDidMount () { let handler = this.handleTouchStart; this.container.addEventListener('touchstart', handler); this.removers.push(() => this.container.removeEventListener('touchstart', handler)); handler = this.handleTouchMove; // on Chrome 56+, touch event listeners will default to passive // https://www.chromestatus.com/features/5093566007214080 this.container.addEventListener('touchmove', handler, { passive: false }); this.removers.push(() => this.container.removeEventListener('touchend', handler)); handler = this.mouseDownHandler; this.container.addEventListener('mousedown', handler); this.removers.push(() => this.container.removeEventListener('mousedown', handler)); handler = this.mouseWheelHandler; this.container.addEventListener('wheel', handler); this.removers.push(() => this.container.removeEventListener('wheel', handler)); // Old Chrome this.container.addEventListener('mousewheel', handler); this.removers.push(() => this.container.removeEventListener('mousewheel', handler)); // Old Firefox this.container.addEventListener('DOMMouseScroll', handler); this.removers.push(() => this.container.removeEventListener('DOMMouseScroll', handler)); this.initZoomMatrix(); } componentWillUnmount () { this.removeEventListeners(); } componentDidUpdate () { if (this.props.zoomButtonHidden) { this.setState({ scale: MIN_SCALE }, () => { this.container.scrollLeft = 0; this.container.scrollTop = 0; }); } this.setState({ zoomState: this.state.scale >= this.state.zoomMatrix.rate ? 'compress' : 'expand' }); if (this.state.scale === 1) { this.container.style.removeProperty('cursor'); } } removeEventListeners () { this.removers.forEach(listeners => listeners()); this.removers = []; } mouseWheelHandler = e => { e.preventDefault(); const event = normalizeWheel(e); if (this.state.zoomMatrix.type === 'full-width') { // full width, scroll vertical this.container.scrollTop = Math.max(this.container.scrollTop + event.pixelY, this.state.lockScroll.y); } else { // full height, scroll horizontal this.container.scrollLeft = Math.max(this.container.scrollLeft + event.pixelY, this.state.lockScroll.x); } // lock horizontal scroll this.container.scrollLeft = Math.max(this.container.scrollLeft + event.pixelX, this.state.lockScroll.x); } mouseDownHandler = e => { this.container.style.cursor = 'grabbing'; this.container.style.userSelect = 'none'; this.setState({ dragPosition: { left: this.container.scrollLeft, top: this.container.scrollTop, // Get the current mouse position x: e.clientX, y: e.clientY, } }); this.image.addEventListener('mousemove', this.mouseMoveHandler); this.image.addEventListener('mouseup', this.mouseUpHandler); } mouseMoveHandler = e => { const dx = e.clientX - this.state.dragPosition.x; const dy = e.clientY - this.state.dragPosition.y; this.container.scrollLeft = Math.max(this.state.dragPosition.left - dx, this.state.lockScroll.x); this.container.scrollTop = Math.max(this.state.dragPosition.top - dy, this.state.lockScroll.y); this.setState({ dragged: true }); } mouseUpHandler = () => { this.container.style.cursor = 'grab'; this.container.style.removeProperty('user-select'); this.image.removeEventListener('mousemove', this.mouseMoveHandler); this.image.removeEventListener('mouseup', this.mouseUpHandler); } handleTouchStart = e => { if (e.touches.length !== 2) return; this.lastDistance = getDistance(...e.touches); } handleTouchMove = e => { const { scrollTop, scrollHeight, clientHeight } = this.container; if (e.touches.length === 1 && scrollTop !== scrollHeight - clientHeight) { // prevent propagating event to MediaModal e.stopPropagation(); return; } if (e.touches.length !== 2) return; e.preventDefault(); e.stopPropagation(); const distance = getDistance(...e.touches); const midpoint = getMidpoint(...e.touches); const _MAX_SCALE = Math.max(MAX_SCALE, this.state.zoomMatrix.rate); const scale = clamp(MIN_SCALE, _MAX_SCALE, this.state.scale * distance / this.lastDistance); this.zoom(scale, midpoint); this.lastMidpoint = midpoint; this.lastDistance = distance; } zoom(nextScale, midpoint) { const { scale } = this.state; const { scrollLeft, scrollTop } = this.container; // math memo: // x = (scrollLeft + midpoint.x) / scrollWidth // x' = (nextScrollLeft + midpoint.x) / nextScrollWidth // scrollWidth = clientWidth * scale // scrollWidth' = clientWidth * nextScale // Solve x = x' for nextScrollLeft const nextScrollLeft = (scrollLeft + midpoint.x) * nextScale / scale - midpoint.x; const nextScrollTop = (scrollTop + midpoint.y) * nextScale / scale - midpoint.y; this.setState({ scale: nextScale }, () => { this.container.scrollLeft = nextScrollLeft; this.container.scrollTop = nextScrollTop; }); } handleClick = e => { // don't propagate event to MediaModal e.stopPropagation(); const dragged = this.state.dragged; this.setState({ dragged: false }); if (dragged) return; const handler = this.props.onClick; if (handler) handler(); this.setState({ navigationHidden: !this.state.navigationHidden }); } handleMouseDown = e => { e.preventDefault(); } initZoomMatrix = () => { const { width, height } = this.props; const { clientWidth, clientHeight } = this.container; const { offsetWidth, offsetHeight } = this.image; const clientHeightFixed = clientHeight - NAV_BAR_HEIGHT; const type = width/height < clientWidth / clientHeightFixed ? 'full-width' : 'full-height'; const rate = type === 'full-width' ? clientWidth / offsetWidth : clientHeightFixed / offsetHeight; const scrollTop = type === 'full-width' ? (clientHeight - offsetHeight) / 2 - NAV_BAR_HEIGHT : (clientHeightFixed - offsetHeight) / 2; const scrollLeft = (clientWidth - offsetWidth) / 2; this.setState({ zoomMatrix: { type: type, rate: rate, clientWidth: clientWidth, clientHeight: clientHeight, offsetWidth: offsetWidth, offsetHeight: offsetHeight, clientHeightFixed: clientHeightFixed, scrollTop: scrollTop, scrollLeft: scrollLeft, }, }); } handleZoomClick = e => { e.preventDefault(); e.stopPropagation(); const { scale, zoomMatrix } = this.state; if ( scale >= zoomMatrix.rate ) { this.setState({ scale: MIN_SCALE, lockScroll: { x: 0, y: 0, }, }, () => { this.container.scrollLeft = 0; this.container.scrollTop = 0; }); } else { this.setState({ scale: zoomMatrix.rate, lockScroll: { x: zoomMatrix.scrollLeft, y: zoomMatrix.scrollTop, }, }, () => { this.container.scrollLeft = zoomMatrix.scrollLeft; this.container.scrollTop = zoomMatrix.scrollTop; }); } this.container.style.cursor = 'grab'; this.container.style.removeProperty('user-select'); } setContainerRef = c => { this.container = c; } setImageRef = c => { this.image = c; } render () { const { alt, src, width, height, intl } = this.props; const { scale } = this.state; const overflow = scale === 1 ? 'hidden' : 'scroll'; const zoomButtonSshouldHide = !this.state.navigationHidden && !this.props.zoomButtonHidden ? '' : 'media-modal__zoom-button--hidden'; const zoomButtonTitle = this.state.zoomState === 'compress' ? intl.formatMessage(messages.compress) : intl.formatMessage(messages.expand); return (
{alt}
); } }