diff options
Diffstat (limited to 'app')
| -rw-r--r-- | app/javascript/mastodon/features/ui/components/zoomable_image.js | 165 | ||||
| -rw-r--r-- | app/javascript/styles/mastodon/components.scss | 3 |
2 files changed, 75 insertions, 93 deletions
diff --git a/app/javascript/mastodon/features/ui/components/zoomable_image.js b/app/javascript/mastodon/features/ui/components/zoomable_image.js index 0cae0862d..0a0a4d41a 100644 --- a/app/javascript/mastodon/features/ui/components/zoomable_image.js +++ b/app/javascript/mastodon/features/ui/components/zoomable_image.js @@ -1,10 +1,16 @@ import React from 'react'; import PropTypes from 'prop-types'; -import Hammer from 'hammerjs'; const MIN_SCALE = 1; const MAX_SCALE = 4; -const DOUBLE_TAP_SCALE = 2; + +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)); @@ -31,95 +37,81 @@ export default class ZoomableImage extends React.PureComponent { removers = []; container = null; image = null; - lastScale = null; - zoomCenter = null; + lastTouchEndTime = 0; + lastDistance = 0; componentDidMount () { - // register pinch event handlers to the container - let hammer = new Hammer.Manager(this.container, { - // required to make container scrollable by touch - touchAction: 'pan-x pan-y', - }); - hammer.add(new Hammer.Pinch()); - hammer.on('pinchstart', this.handlePinchStart); - hammer.on('pinchmove', this.handlePinchMove); - this.removers.push(() => hammer.off('pinchstart pinchmove')); - - // register tap event handlers - hammer = new Hammer.Manager(this.image); - // NOTE the order of adding is also the order of gesture recognition - hammer.add(new Hammer.Tap({ event: 'doubletap', taps: 2 })); - hammer.add(new Hammer.Tap()); - // prevent the 'tap' event handler be fired on double tap - hammer.get('tap').requireFailure('doubletap'); - // NOTE 'tap' and 'doubletap' events are fired by touch and *mouse* - hammer.on('tap', this.handleTap); - hammer.on('doubletap', this.handleDoubleTap); - this.removers.push(() => hammer.off('tap doubletap')); + 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)); } componentWillUnmount () { this.removeEventListeners(); } - componentDidUpdate (prevProps, prevState) { - if (!this.zoomCenter) return; - - const { x: cx, y: cy } = this.zoomCenter; - const { scale: prevScale } = prevState; - const { scale: nextScale } = this.state; - const { scrollLeft, scrollTop } = this.container; - - // math memo: - // x = (scrollLeft + cx) / scrollWidth - // x' = (nextScrollLeft + cx) / nextScrollWidth - // scrollWidth = clientWidth * prevScale - // scrollWidth' = clientWidth * nextScale - // Solve x = x' for nextScrollLeft - const nextScrollLeft = (scrollLeft + cx) * nextScale / prevScale - cx; - const nextScrollTop = (scrollTop + cy) * nextScale / prevScale - cy; - - this.container.scrollLeft = nextScrollLeft; - this.container.scrollTop = nextScrollTop; - } - removeEventListeners () { this.removers.forEach(listeners => listeners()); this.removers = []; } - handleClick = e => { - // prevent the click event propagated to parent - e.stopPropagation(); + handleTouchStart = e => { + if (e.touches.length !== 2) return; - // the tap event handler is executed at the same time by touch and mouse, - // so we don't need to execute the onClick handler here + this.lastDistance = getDistance(...e.touches); } - handlePinchStart = () => { - this.lastScale = this.state.scale; - } + 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; - handlePinchMove = e => { - const scale = clamp(MIN_SCALE, MAX_SCALE, this.lastScale * e.scale); - this.zoom(scale, e.center); - } + e.preventDefault(); + e.stopPropagation(); - handleTap = () => { - const handler = this.props.onClick; - if (handler) handler(); + const distance = getDistance(...e.touches); + const midpoint = getMidpoint(...e.touches); + const scale = clamp(MIN_SCALE, MAX_SCALE, this.state.scale * distance / this.lastDistance); + + this.zoom(scale, midpoint); + + this.lastMidpoint = midpoint; + this.lastDistance = distance; } - handleDoubleTap = e => { - if (this.state.scale === MIN_SCALE) - this.zoom(DOUBLE_TAP_SCALE, e.center); - else - this.zoom(MIN_SCALE, e.center); + 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; + }); } - zoom (scale, center) { - this.zoomCenter = center; - this.setState({ scale }); + handleClick = e => { + // don't propagate event to MediaModal + e.stopPropagation(); + const handler = this.props.onClick; + if (handler) handler(); } setContainerRef = c => { @@ -134,18 +126,6 @@ export default class ZoomableImage extends React.PureComponent { const { alt, src } = this.props; const { scale } = this.state; const overflow = scale === 1 ? 'hidden' : 'scroll'; - const marginStyle = { - position: 'absolute', - top: 0, - bottom: 0, - left: 0, - right: 0, - display: 'flex', - alignItems: 'center', - justifyContent: 'center', - transform: `scale(${scale})`, - transformOrigin: '0 0', - }; return ( <div @@ -153,18 +133,17 @@ export default class ZoomableImage extends React.PureComponent { ref={this.setContainerRef} style={{ overflow }} > - <div - className='zoomable-image__margin' - style={marginStyle} - > - <img - ref={this.setImageRef} - role='presentation' - alt={alt} - src={src} - onClick={this.handleClick} - /> - </div> + <img + role='presentation' + ref={this.setImageRef} + alt={alt} + src={src} + style={{ + transform: `scale(${scale})`, + transformOrigin: '0 0', + }} + onClick={this.handleClick} + /> </div> ); } diff --git a/app/javascript/styles/mastodon/components.scss b/app/javascript/styles/mastodon/components.scss index 6a83be452..d76dc10f1 100644 --- a/app/javascript/styles/mastodon/components.scss +++ b/app/javascript/styles/mastodon/components.scss @@ -1483,6 +1483,9 @@ position: relative; width: 100%; height: 100%; + display: flex; + align-items: center; + justify-content: center; img { max-width: $media-modal-media-max-width; |