460 lines
		
	
	
	
		
			14 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			460 lines
		
	
	
	
		
			14 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| import PropTypes from 'prop-types';
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| import { PureComponent } from 'react';
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| 
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| import { defineMessages, injectIntl } from 'react-intl';
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| 
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| import { ReactComponent as FullscreenExitIcon } from '@material-symbols/svg-600/outlined/fullscreen_exit.svg';
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| import { ReactComponent as RectangleIcon } from '@material-symbols/svg-600/outlined/rectangle.svg';
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| 
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| import { IconButton } from 'mastodon/components/icon_button';
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| 
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| const messages = defineMessages({
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|   compress: { id: 'lightbox.compress', defaultMessage: 'Compress image view box' },
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|   expand: { id: 'lightbox.expand', defaultMessage: 'Expand image view box' },
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| });
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| 
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| const MIN_SCALE = 1;
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| const MAX_SCALE = 4;
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| const NAV_BAR_HEIGHT = 66;
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| 
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| const getMidpoint = (p1, p2) => ({
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|   x: (p1.clientX + p2.clientX) / 2,
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|   y: (p1.clientY + p2.clientY) / 2,
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| });
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| 
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| const getDistance = (p1, p2) =>
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|   Math.sqrt(Math.pow(p1.clientX - p2.clientX, 2) + Math.pow(p1.clientY - p2.clientY, 2));
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| 
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| const clamp = (min, max, value) => Math.min(max, Math.max(min, value));
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| 
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| // Normalizing mousewheel speed across browsers
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| // copy from: https://github.com/facebookarchive/fixed-data-table/blob/master/src/vendor_upstream/dom/normalizeWheel.js
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| const normalizeWheel = event => {
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|   // Reasonable defaults
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|   const PIXEL_STEP = 10;
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|   const LINE_HEIGHT = 40;
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|   const PAGE_HEIGHT = 800;
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| 
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|   let sX = 0,
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|     sY = 0, // spinX, spinY
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|     pX = 0,
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|     pY = 0; // pixelX, pixelY
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| 
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|   // Legacy
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|   if ('detail' in event) {
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|     sY = event.detail;
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|   }
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|   if ('wheelDelta' in event) {
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|     sY = -event.wheelDelta / 120;
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|   }
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|   if ('wheelDeltaY' in event) {
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|     sY = -event.wheelDeltaY / 120;
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|   }
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|   if ('wheelDeltaX' in event) {
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|     sX = -event.wheelDeltaX / 120;
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|   }
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| 
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|   // side scrolling on FF with DOMMouseScroll
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|   if ('axis' in event && event.axis === event.HORIZONTAL_AXIS) {
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|     sX = sY;
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|     sY = 0;
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|   }
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| 
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|   pX = sX * PIXEL_STEP;
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|   pY = sY * PIXEL_STEP;
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| 
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|   if ('deltaY' in event) {
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|     pY = event.deltaY;
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|   }
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|   if ('deltaX' in event) {
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|     pX = event.deltaX;
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|   }
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| 
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|   if ((pX || pY) && event.deltaMode) {
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|     if (event.deltaMode === 1) { // delta in LINE units
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|       pX *= LINE_HEIGHT;
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|       pY *= LINE_HEIGHT;
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|     } else { // delta in PAGE units
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|       pX *= PAGE_HEIGHT;
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|       pY *= PAGE_HEIGHT;
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|     }
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|   }
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| 
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|   // Fall-back if spin cannot be determined
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|   if (pX && !sX) {
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|     sX = (pX < 1) ? -1 : 1;
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|   }
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|   if (pY && !sY) {
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|     sY = (pY < 1) ? -1 : 1;
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|   }
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| 
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|   return {
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|     spinX: sX,
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|     spinY: sY,
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|     pixelX: pX,
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|     pixelY: pY,
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|   };
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| };
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| 
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| class ZoomableImage extends PureComponent {
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| 
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|   static propTypes = {
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|     alt: PropTypes.string,
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|     lang: PropTypes.string,
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|     src: PropTypes.string.isRequired,
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|     width: PropTypes.number,
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|     height: PropTypes.number,
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|     onClick: PropTypes.func,
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|     zoomButtonHidden: PropTypes.bool,
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|     intl: PropTypes.object.isRequired,
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|   };
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| 
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|   static defaultProps = {
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|     alt: '',
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|     lang: '',
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|     width: null,
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|     height: null,
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|   };
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| 
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|   state = {
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|     scale: MIN_SCALE,
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|     zoomMatrix: {
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|       type: null, // 'width' 'height'
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|       fullScreen: null, // bool
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|       rate: null, // full screen scale rate
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|       clientWidth: null,
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|       clientHeight: null,
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|       offsetWidth: null,
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|       offsetHeight: null,
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|       clientHeightFixed: null,
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|       scrollTop: null,
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|       scrollLeft: null,
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|       translateX: null,
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|       translateY: null,
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|     },
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|     zoomState: 'expand', // 'expand' 'compress'
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|     navigationHidden: false,
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|     dragPosition: { top: 0, left: 0, x: 0, y: 0 },
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|     dragged: false,
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|     lockScroll: { x: 0, y: 0 },
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|     lockTranslate: { x: 0, y: 0 },
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|   };
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| 
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|   removers = [];
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|   container = null;
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|   image = null;
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|   lastTouchEndTime = 0;
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|   lastDistance = 0;
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| 
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|   componentDidMount () {
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|     let handler = this.handleTouchStart;
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|     this.container.addEventListener('touchstart', handler);
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|     this.removers.push(() => this.container.removeEventListener('touchstart', handler));
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|     handler = this.handleTouchMove;
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|     // on Chrome 56+, touch event listeners will default to passive
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|     // https://www.chromestatus.com/features/5093566007214080
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|     this.container.addEventListener('touchmove', handler, { passive: false });
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|     this.removers.push(() => this.container.removeEventListener('touchend', handler));
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| 
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|     handler = this.mouseDownHandler;
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|     this.container.addEventListener('mousedown', handler);
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|     this.removers.push(() => this.container.removeEventListener('mousedown', handler));
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| 
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|     handler = this.mouseWheelHandler;
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|     this.container.addEventListener('wheel', handler);
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|     this.removers.push(() => this.container.removeEventListener('wheel', handler));
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|     // Old Chrome
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|     this.container.addEventListener('mousewheel', handler);
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|     this.removers.push(() => this.container.removeEventListener('mousewheel', handler));
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|     // Old Firefox
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|     this.container.addEventListener('DOMMouseScroll', handler);
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|     this.removers.push(() => this.container.removeEventListener('DOMMouseScroll', handler));
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| 
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|     this.initZoomMatrix();
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|   }
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| 
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|   componentWillUnmount () {
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|     this.removeEventListeners();
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|   }
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| 
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|   componentDidUpdate () {
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|     this.setState({ zoomState: this.state.scale >= this.state.zoomMatrix.rate ? 'compress' : 'expand' });
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| 
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|     if (this.state.scale === MIN_SCALE) {
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|       this.container.style.removeProperty('cursor');
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|     }
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|   }
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| 
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|   UNSAFE_componentWillReceiveProps () {
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|     // reset when slide to next image
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|     if (this.props.zoomButtonHidden) {
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|       this.setState({
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|         scale: MIN_SCALE,
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|         lockTranslate: { x: 0, y: 0 },
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|       }, () => {
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|         this.container.scrollLeft = 0;
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|         this.container.scrollTop = 0;
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|       });
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|     }
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|   }
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| 
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|   removeEventListeners () {
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|     this.removers.forEach(listeners => listeners());
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|     this.removers = [];
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|   }
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| 
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|   mouseWheelHandler = e => {
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|     e.preventDefault();
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| 
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|     const event = normalizeWheel(e);
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| 
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|     if (this.state.zoomMatrix.type === 'width') {
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|       // full width, scroll vertical
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|       this.container.scrollTop = Math.max(this.container.scrollTop + event.pixelY, this.state.lockScroll.y);
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|     } else {
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|       // full height, scroll horizontal
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|       this.container.scrollLeft = Math.max(this.container.scrollLeft + event.pixelY, this.state.lockScroll.x);
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|     }
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| 
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|     // lock horizontal scroll
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|     this.container.scrollLeft = Math.max(this.container.scrollLeft + event.pixelX, this.state.lockScroll.x);
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|   };
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| 
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|   mouseDownHandler = e => {
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|     this.container.style.cursor = 'grabbing';
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|     this.container.style.userSelect = 'none';
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| 
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|     this.setState({ dragPosition: {
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|       left: this.container.scrollLeft,
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|       top: this.container.scrollTop,
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|       // Get the current mouse position
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|       x: e.clientX,
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|       y: e.clientY,
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|     } });
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| 
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|     this.image.addEventListener('mousemove', this.mouseMoveHandler);
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|     this.image.addEventListener('mouseup', this.mouseUpHandler);
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|   };
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| 
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|   mouseMoveHandler = e => {
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|     const dx = e.clientX - this.state.dragPosition.x;
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|     const dy = e.clientY - this.state.dragPosition.y;
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| 
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|     this.container.scrollLeft = Math.max(this.state.dragPosition.left - dx, this.state.lockScroll.x);
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|     this.container.scrollTop = Math.max(this.state.dragPosition.top - dy, this.state.lockScroll.y);
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| 
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|     this.setState({ dragged: true });
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|   };
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| 
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|   mouseUpHandler = () => {
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|     this.container.style.cursor = 'grab';
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|     this.container.style.removeProperty('user-select');
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| 
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|     this.image.removeEventListener('mousemove', this.mouseMoveHandler);
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|     this.image.removeEventListener('mouseup', this.mouseUpHandler);
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|   };
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| 
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|   handleTouchStart = e => {
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|     if (e.touches.length !== 2) return;
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| 
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|     this.lastDistance = getDistance(...e.touches);
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|   };
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| 
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|   handleTouchMove = e => {
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|     const { scrollTop, scrollHeight, clientHeight } = this.container;
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|     if (e.touches.length === 1 && scrollTop !== scrollHeight - clientHeight) {
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|       // prevent propagating event to MediaModal
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|       e.stopPropagation();
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|       return;
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|     }
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|     if (e.touches.length !== 2) return;
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| 
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|     e.preventDefault();
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|     e.stopPropagation();
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| 
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|     const distance = getDistance(...e.touches);
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|     const midpoint = getMidpoint(...e.touches);
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|     const _MAX_SCALE = Math.max(MAX_SCALE, this.state.zoomMatrix.rate);
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|     const scale = clamp(MIN_SCALE, _MAX_SCALE, this.state.scale * distance / this.lastDistance);
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| 
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|     this.zoom(scale, midpoint);
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| 
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|     this.lastMidpoint = midpoint;
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|     this.lastDistance = distance;
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|   };
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| 
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|   zoom(nextScale, midpoint) {
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|     const { scale, zoomMatrix } = this.state;
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|     const { scrollLeft, scrollTop } = this.container;
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| 
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|     // math memo:
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|     // x = (scrollLeft + midpoint.x) / scrollWidth
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|     // x' = (nextScrollLeft + midpoint.x) / nextScrollWidth
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|     // scrollWidth = clientWidth * scale
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|     // scrollWidth' = clientWidth * nextScale
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|     // Solve x = x' for nextScrollLeft
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|     const nextScrollLeft = (scrollLeft + midpoint.x) * nextScale / scale - midpoint.x;
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|     const nextScrollTop = (scrollTop + midpoint.y) * nextScale / scale - midpoint.y;
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| 
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|     this.setState({ scale: nextScale }, () => {
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|       this.container.scrollLeft = nextScrollLeft;
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|       this.container.scrollTop = nextScrollTop;
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|       // reset the translateX/Y constantly
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|       if (nextScale < zoomMatrix.rate) {
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|         this.setState({
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|           lockTranslate: {
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|             x: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateX * ((nextScale - MIN_SCALE) / (zoomMatrix.rate - MIN_SCALE)),
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|             y: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateY * ((nextScale - MIN_SCALE) / (zoomMatrix.rate - MIN_SCALE)),
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|           },
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|         });
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|       }
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|     });
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|   }
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| 
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|   handleClick = e => {
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|     // don't propagate event to MediaModal
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|     e.stopPropagation();
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|     const dragged = this.state.dragged;
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|     this.setState({ dragged: false });
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|     if (dragged) return;
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|     const handler = this.props.onClick;
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|     if (handler) handler();
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|     this.setState({ navigationHidden: !this.state.navigationHidden });
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|   };
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| 
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|   handleMouseDown = e => {
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|     e.preventDefault();
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|   };
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| 
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|   initZoomMatrix = () => {
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|     const { width, height } = this.props;
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|     const { clientWidth, clientHeight } = this.container;
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|     const { offsetWidth, offsetHeight } = this.image;
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|     const clientHeightFixed = clientHeight - NAV_BAR_HEIGHT;
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| 
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|     const type = width / height < clientWidth / clientHeightFixed ? 'width' : 'height';
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|     const fullScreen = type === 'width' ?  width > clientWidth : height > clientHeightFixed;
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|     const rate = type === 'width' ? Math.min(clientWidth, width) / offsetWidth : Math.min(clientHeightFixed, height) / offsetHeight;
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|     const scrollTop = type === 'width' ?  (clientHeight - offsetHeight) / 2 - NAV_BAR_HEIGHT : (clientHeightFixed - offsetHeight) / 2;
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|     const scrollLeft = (clientWidth - offsetWidth) / 2;
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|     const translateX = type === 'width' ? (width - offsetWidth) / (2 * rate) : 0;
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|     const translateY = type === 'height' ? (height - offsetHeight) / (2 * rate) : 0;
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| 
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|     this.setState({
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|       zoomMatrix: {
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|         type: type,
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|         fullScreen: fullScreen,
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|         rate: rate,
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|         clientWidth: clientWidth,
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|         clientHeight: clientHeight,
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|         offsetWidth: offsetWidth,
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|         offsetHeight: offsetHeight,
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|         clientHeightFixed: clientHeightFixed,
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|         scrollTop: scrollTop,
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|         scrollLeft: scrollLeft,
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|         translateX: translateX,
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|         translateY: translateY,
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|       },
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|     });
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|   };
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| 
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|   handleZoomClick = e => {
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|     e.preventDefault();
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|     e.stopPropagation();
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| 
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|     const { scale, zoomMatrix } = this.state;
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| 
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|     if ( scale >= zoomMatrix.rate ) {
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|       this.setState({
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|         scale: MIN_SCALE,
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|         lockScroll: {
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|           x: 0,
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|           y: 0,
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|         },
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|         lockTranslate: {
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|           x: 0,
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|           y: 0,
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|         },
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|       }, () => {
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|         this.container.scrollLeft = 0;
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|         this.container.scrollTop = 0;
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|       });
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|     } else {
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|       this.setState({
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|         scale: zoomMatrix.rate,
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|         lockScroll: {
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|           x: zoomMatrix.scrollLeft,
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|           y: zoomMatrix.scrollTop,
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|         },
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|         lockTranslate: {
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|           x: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateX,
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|           y: zoomMatrix.fullScreen ? 0 : zoomMatrix.translateY,
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|         },
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|       }, () => {
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|         this.container.scrollLeft = zoomMatrix.scrollLeft;
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|         this.container.scrollTop = zoomMatrix.scrollTop;
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|       });
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|     }
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| 
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|     this.container.style.cursor = 'grab';
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|     this.container.style.removeProperty('user-select');
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|   };
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| 
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|   setContainerRef = c => {
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|     this.container = c;
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|   };
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| 
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|   setImageRef = c => {
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|     this.image = c;
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|   };
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| 
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|   render () {
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|     const { alt, lang, src, width, height, intl } = this.props;
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|     const { scale, lockTranslate } = this.state;
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|     const overflow = scale === MIN_SCALE ? 'hidden' : 'scroll';
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|     const zoomButtonShouldHide = this.state.navigationHidden || this.props.zoomButtonHidden || this.state.zoomMatrix.rate <= MIN_SCALE ? 'media-modal__zoom-button--hidden' : '';
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|     const zoomButtonTitle = this.state.zoomState === 'compress' ? intl.formatMessage(messages.compress) : intl.formatMessage(messages.expand);
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| 
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|     return (
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|       <>
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|         <IconButton
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|           className={`media-modal__zoom-button ${zoomButtonShouldHide}`}
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|           title={zoomButtonTitle}
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|           icon={this.state.zoomState}
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|           iconComponent={this.state.zoomState === 'compress' ? FullscreenExitIcon : RectangleIcon}
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|           onClick={this.handleZoomClick}
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|           size={40}
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|           style={{
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|             fontSize: '30px', /* Fontawesome's fa-compress fa-expand is larger than fa-close */
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|           }}
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|         />
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|         <div
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|           className='zoomable-image'
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|           ref={this.setContainerRef}
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|           style={{ overflow }}
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|         >
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|           <img
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|             role='presentation'
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|             ref={this.setImageRef}
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|             alt={alt}
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|             title={alt}
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|             lang={lang}
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|             src={src}
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|             width={width}
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|             height={height}
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|             style={{
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|               transform: `scale(${scale}) translate(-${lockTranslate.x}px, -${lockTranslate.y}px)`,
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|               transformOrigin: '0 0',
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|             }}
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|             draggable={false}
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|             onClick={this.handleClick}
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|             onMouseDown={this.handleMouseDown}
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|           />
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|         </div>
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|       </>
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|     );
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|   }
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| 
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| }
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| 
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| export default injectIntl(ZoomableImage);
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