Photoswipe Responsive Images

[davidhellmann]

import $ from 'jquery';
import PhotoSwipe from 'photoswipe';
import PhotoSwipeUI_Default from '../../../node_modules/photoswipe/dist/photoswipe-ui-default';


var initPhotoSwipeFromDOM = function(gallerySelector) {

    // parse slide data (url, title, size ...) from DOM elements
    // (children of gallerySelector)
    var parseThumbnailElements = function(el) {
        var thumbElements = el.querySelectorAll('.masonry__item'),
            numNodes = thumbElements.length,
            items = [],
            figureEl,
            linkEl,
            size,
            item;
        for(var i = 0; i < numNodes; i++) {
            figureEl = thumbElements[i].children[0]; // <figure> element
            // include only element nodes
            if(figureEl.nodeType !== 1) {
                continue;
            }

            linkEl = figureEl.children[0]; // <a> element

            size = linkEl.getAttribute('data-size').split('x');

            // create slide object
            item = {
                src: linkEl.getAttribute('href'),
                w: parseInt(size[0], 10),
                h: parseInt(size[1], 10)
            };

            var mediumSrc = linkEl.getAttribute('data-medium');
            var smallSrc = linkEl.getAttribute('data-small');

            if(mediumSrc) {
                var size = linkEl.getAttribute('data-medium-size').split('x');
                item.mediumImage = {
                    src: mediumSrc,
                    w: parseInt(size[0], 10),
                    h: parseInt(size[1], 10)
                }
            }

            if(smallSrc) {
                var size = linkEl.getAttribute('data-small-size').split('x');
                item.smallImage = {
                    src: smallSrc,
                    w: parseInt(size[0], 10),
                    h: parseInt(size[1], 10)
                };
            }

            item.originalImage = {
                src: item.src,
                w: item.w,
                h: item.h
            }



            if(figureEl.children.length > 1) {
                // <figcaption> content
                item.title = figureEl.children[1].innerHTML;
            }

            if(linkEl.children.length > 0) {
                // <img> thumbnail element, retrieving thumbnail url
                item.msrc = linkEl.children[0].getAttribute('src');
            }

            item.el = figureEl; // save link to element for getThumbBoundsFn
            items.push(item);
        }

        return items;
    };

    // find nearest parent element
    var closest = function closest(el, fn) {
        return el && ( fn(el) ? el : closest(el.parentNode, fn) );
    };

    // triggers when user clicks on thumbnail
    var onThumbnailsClick = function(e) {
        e = e || window.event;
        e.preventDefault ? e.preventDefault() : e.returnValue = false;
        var eTarget = e.target || e.srcElement;

        // find root element of slide
        var clickedListItem = closest(eTarget, function(el) {
            return (el.tagName && el.tagName.toUpperCase() === 'FIGURE');
        });

        if(!clickedListItem) {
            return;
        }

        // find index of clicked item by looping through all child nodes
        // alternatively, you may define index via data- attribute
        clickedListItem = clickedListItem.parentNode;
        var clickedGallery = clickedListItem.parentNode,
            childNodes = clickedListItem.parentNode.querySelectorAll('.masonry__item'),
            numChildNodes = childNodes.length,
            nodeIndex = 0,
            index;

        for (var i = 0; i < numChildNodes; i++) {
            if(childNodes[i].nodeType !== 1) {
                continue;
            }

            if(childNodes[i] === clickedListItem) {
                index = nodeIndex;
                break;
            }
            nodeIndex++;
        }

        if(index >= 0) {
            // open PhotoSwipe if valid index found
            openPhotoSwipe( index, clickedGallery );
        }
        return false;
    };

    // parse picture index and gallery index from URL (#&pid=1&gid=2)
    var photoswipeParseHash = function() {
        var hash = window.location.hash.substring(1),
            params = {};

        if(hash.length < 5) {
            return params;
        }

        var vars = hash.split('&');
        for (var i = 0; i < vars.length; i++) {
            if(!vars[i]) {
                continue;
            }
            var pair = vars[i].split('=');
            if(pair.length < 2) {
                continue;
            }
            params[pair[0]] = pair[1];
        }

        if(params.gid) {
            params.gid = parseInt(params.gid, 10);
        }

        return params;
    };

    var openPhotoSwipe = function(index, galleryElement, disableAnimation, fromURL) {
        var pswpElement = document.querySelectorAll('.pswp')[0],
            gallery,
            options,
            items;

        items = parseThumbnailElements(galleryElement);

        // define options (if needed)
        options = {

            // define gallery index (for URL)
            galleryUID: galleryElement.getAttribute('data-pswp-uid'),

            getThumbBoundsFn: function(index) {
                // See Options -> getThumbBoundsFn section of documentation for more info
                var thumbnail = items[index].el.getElementsByTagName('img')[0], // find thumbnail
                    pageYScroll = window.pageYOffset || document.documentElement.scrollTop,
                    rect = thumbnail.getBoundingClientRect();

                return {x:rect.left, y:rect.top + pageYScroll, w:rect.width};
            },
            captionEl: false,
            fullscreenEl: false,
            zoomEl: false,
            shareEl: false,
            timeToIdle: 8000, // default 4000
            maxSpreadZoom: 1,
            getDoubleTapZoom: function(isMouseClick, item) {
                return item.initialZoomLevel;
            },
            pinchToClose: false
        };

        // PhotoSwipe opened from URL
        if(fromURL) {
            if(options.galleryPIDs) {
                // parse real index when custom PIDs are used
                // http://photoswipe.com/documentation/faq.html#custom-pid-in-url
                for(var j = 0; j < items.length; j++) {
                    if(items[j].pid == index) {
                        options.index = j;
                        break;
                    }
                }
            } else {
                // in URL indexes start from 1
                options.index = parseInt(index, 10) - 1;
            }
        } else {
            options.index = parseInt(index, 10);
        }

        // exit if index not found
        if( isNaN(options.index) ) {
            return;
        }

        if(disableAnimation) {
            options.showAnimationDuration = 0;
        }

        // Pass data to PhotoSwipe and initialize it
        gallery = new PhotoSwipe( pswpElement, PhotoSwipeUI_Default, items, options);


        // create variable that will store real size of viewport
        var realViewportWidth,
            useLargeImages = false,
            useMediumImages = false,
            useSmallImages = false,
            firstResize = true,
            imageSrcWillChange;

// beforeResize event fires each time size of gallery viewport updates
        gallery.listen('beforeResize', function() {
            // gallery.viewportSize.x - width of PhotoSwipe viewport
            // gallery.viewportSize.y - height of PhotoSwipe viewport
            // window.devicePixelRatio - ratio between physical pixels and device independent pixels (Number)
            //                          1 (regular display), 2 (@2x, retina) ...


            // calculate real pixels when size changes
            realViewportWidth = gallery.viewportSize.x * window.devicePixelRatio;

            // Code below is needed if you want image to switch dynamically on window.resize

            // Find out if current images need to be changed
            if(realViewportWidth < 640) {
                useLargeImages = false;
                useMediumImages = false;
                useSmallImages = true;
                imageSrcWillChange = true
            } else if (realViewportWidth < 1000 && realViewportWidth >= 640) {
                useLargeImages = false;
                useMediumImages = true;
                useSmallImages = false;
                imageSrcWillChange = true;
            } else if (realViewportWidth >= 1000) {
                useLargeImages = true;
                useMediumImages = false;
                useSmallImages = false;
                imageSrcWillChange = true;
            }

            //if(useLargeImages && realViewportWidth < 1000) {
            //
            //} else if(!useLargeImages && realViewportWidth >= 1000) {
            //    useLargeImages = true;
            //    imageSrcWillChange = true;
            //}

            // Invalidate items only when source is changed and when it's not the first update
            if(imageSrcWillChange && !firstResize) {
                // invalidateCurrItems sets a flag on slides that are in DOM,
                // which will force update of content (image) on window.resize.
                gallery.invalidateCurrItems();
            }

            if(firstResize) {
                firstResize = false;
            }

            imageSrcWillChange = false;

        });


// gettingData event fires each time PhotoSwipe retrieves image source & size
        gallery.listen('gettingData', function(index, item) {

            // Set image source & size based on real viewport width
            if( useLargeImages ) {
                item.src = item.originalImage.src;
                item.w = item.originalImage.w;
                item.h = item.originalImage.h;
            } else if (useMediumImages) {
                item.src = item.mediumImage.src;
                item.w = item.mediumImage.w;
                item.h = item.mediumImage.h;
            } else if(useSmallImages) {
                item.src = item.smallImage.src;
                item.w = item.smallImage.w;
                item.h = item.smallImage.h;
            }

            // It doesn't really matter what will you do here,
            // as long as item.src, item.w and item.h have valid values.
            //
            // Just avoid http requests in this listener, as it fires quite often

        });


        gallery.init();
    };

    // loop through all gallery elements and bind events
    var galleryElements = document.querySelectorAll( gallerySelector );

    for(var i = 0, l = galleryElements.length; i < l; i++) {
        galleryElements[i].setAttribute('data-pswp-uid', i+1);
        galleryElements[i].onclick = onThumbnailsClick;
    }

    // Parse URL and open gallery if it contains #&pid=3&gid=1
    var hashData = photoswipeParseHash();
    if(hashData.pid && hashData.gid) {
        openPhotoSwipe( hashData.pid ,  galleryElements[ hashData.gid - 1 ], true, true );
    }
};

// execute above function
initPhotoSwipeFromDOM('.js-lightbox');