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Diffstat (limited to 'app/javascript/flavours/glitch/features/ui/components/zoomable_image.jsx')
| -rw-r--r-- | app/javascript/flavours/glitch/features/ui/components/zoomable_image.jsx | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/app/javascript/flavours/glitch/features/ui/components/zoomable_image.jsx b/app/javascript/flavours/glitch/features/ui/components/zoomable_image.jsx new file mode 100644 index 000000000..47401cfe4 --- /dev/null +++ b/app/javascript/flavours/glitch/features/ui/components/zoomable_image.jsx @@ -0,0 +1,454 @@ +import React from 'react'; +import PropTypes from 'prop-types'; +import IconButton from 'flavours/glitch/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, + }; +}; + +class ZoomableImage extends React.PureComponent { + + static propTypes = { + alt: PropTypes.string, + lang: 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: '', + lang: '', + width: null, + height: null, + }; + + state = { + scale: MIN_SCALE, + zoomMatrix: { + type: null, // 'width' 'height' + fullScreen: null, // bool + rate: null, // full screen scale rate + clientWidth: null, + clientHeight: null, + offsetWidth: null, + offsetHeight: null, + clientHeightFixed: null, + scrollTop: null, + scrollLeft: null, + translateX: null, + translateY: null, + }, + zoomState: 'expand', // 'expand' 'compress' + navigationHidden: false, + dragPosition: { top: 0, left: 0, x: 0, y: 0 }, + dragged: false, + lockScroll: { x: 0, y: 0 }, + lockTranslate: { 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 () { + this.setState({ zoomState: this.state.scale >= this.state.zoomMatrix.rate ? 'compress' : 'expand' }); + + if (this.state.scale === MIN_SCALE) { + this.container.style.removeProperty('cursor'); + } + } + + UNSAFE_componentWillReceiveProps () { + // reset when slide to next image + if (this.props.zoomButtonHidden) { + this.setState({ + scale: MIN_SCALE, + lockTranslate: { x: 0, y: 0 }, + }, () => { + this.container.scrollLeft = 0; + this.container.scrollTop = 0; + }); + } + } + + removeEventListeners () { + this.removers.forEach(listeners => listeners()); + this.removers = []; + } + + mouseWheelHandler = e => { + e.preventDefault(); + + const event = normalizeWheel(e); + + if (this.state.zoomMatrix.type === '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, zoomMatrix } = 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; + // reset the translateX/Y constantly + if (nextScale < zoomMatrix.rate) { + this.setState({ + lockTranslate: { + x: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateX * ((nextScale - MIN_SCALE) / (zoomMatrix.rate - MIN_SCALE)), + y: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateY * ((nextScale - MIN_SCALE) / (zoomMatrix.rate - MIN_SCALE)), + }, + }); + } + }); + } + + 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 ? 'width' : 'height'; + const fullScreen = type === 'width' ? width > clientWidth : height > clientHeightFixed; + const rate = type === 'width' ? Math.min(clientWidth, width) / offsetWidth : Math.min(clientHeightFixed, height) / offsetHeight; + const scrollTop = type === 'width' ? (clientHeight - offsetHeight) / 2 - NAV_BAR_HEIGHT : (clientHeightFixed - offsetHeight) / 2; + const scrollLeft = (clientWidth - offsetWidth) / 2; + const translateX = type === 'width' ? (width - offsetWidth) / (2 * rate) : 0; + const translateY = type === 'height' ? (height - offsetHeight) / (2 * rate) : 0; + + this.setState({ + zoomMatrix: { + type: type, + fullScreen: fullScreen, + rate: rate, + clientWidth: clientWidth, + clientHeight: clientHeight, + offsetWidth: offsetWidth, + offsetHeight: offsetHeight, + clientHeightFixed: clientHeightFixed, + scrollTop: scrollTop, + scrollLeft: scrollLeft, + translateX: translateX, + translateY: translateY, + }, + }); + }; + + 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, + }, + lockTranslate: { + 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, + }, + lockTranslate: { + x: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateX, + y: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateY, + }, + }, () => { + 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, lang, src, width, height, intl } = this.props; + const { scale, lockTranslate } = this.state; + const overflow = scale === MIN_SCALE ? 'hidden' : 'scroll'; + const zoomButtonShouldHide = this.state.navigationHidden || this.props.zoomButtonHidden || this.state.zoomMatrix.rate <= MIN_SCALE ? 'media-modal__zoom-button--hidden' : ''; + const zoomButtonTitle = this.state.zoomState === 'compress' ? intl.formatMessage(messages.compress) : intl.formatMessage(messages.expand); + + return ( + <React.Fragment> + <IconButton + className={`media-modal__zoom-button ${zoomButtonShouldHide}`} + title={zoomButtonTitle} + icon={this.state.zoomState} + onClick={this.handleZoomClick} + size={40} + style={{ + fontSize: '30px', /* Fontawesome's fa-compress fa-expand is larger than fa-close */ + }} + /> + <div + className='zoomable-image' + ref={this.setContainerRef} + style={{ overflow }} + > + <img + role='presentation' + ref={this.setImageRef} + alt={alt} + title={alt} + lang={lang} + src={src} + width={width} + height={height} + style={{ + transform: `scale(${scale}) translate(-${lockTranslate.x}px, -${lockTranslate.y}px)`, + transformOrigin: '0 0', + }} + draggable={false} + onClick={this.handleClick} + onMouseDown={this.handleMouseDown} + /> + </div> + </React.Fragment> + ); + } + +} + +export default injectIntl(ZoomableImage); |