site-accueil-insa/assets/js/photos.js

let showcase = $("#imgBig");
let showcaseButtonContainer = $("#photoButtonsContainer");
let showcaseDownload = $("#downloadButton");
let photoOverlay = $("#photoOverlay");
let headerTop = $("#header-top");
let sideNav = $("#menuSidenav");
let loading = $("#loadingIconContainer");
let move_photo = false;
let grab_offsetX = 0;
let grab_offsetY = 0;

let idle_time = 0;
let isMobile = window.matchMedia("only screen and (max-width: 480px)").matches;
let isMouseOverButtons = false;

$(document).ready(
    function () {
        showcase.bind("mousewheel", function(event, delta) {
            let min_width = $(window).width() / 5;
            let min_height = $(window).height() / 5;
            let max_width = $(window).width() * 5;
            let max_height = $(window).height() * 5;

            let scale = 150 / 100;
            if (delta < 0)
               scale = 1/scale;
            let cursorY = event.pageY - $(window).scrollTop();
            let offsetX = event.pageX - (showcase.position().left + showcase.width()/2);
            let offsetY = cursorY - (showcase.position().top + showcase.height()/2);

            let new_width = showcase.width() * scale;
            let new_height = showcase.height() * scale;
            if (new_width > max_width || new_width < min_width)
                new_width = 0;
            if (new_height > max_height || new_height < min_height)
                new_height = 0;

            if (new_width !== 0 && new_height !== 0){
                let new_left = event.pageX - (offsetX * scale);
                let new_top = cursorY - (offsetY * scale);

                showcase.width(new_width);
                showcase.height(new_height);

                if (new_height > $(window).height() || new_width > $(window).width()){
                    showcase.css('left', new_left +'px');
                    showcase.css('top', new_top +'px');
                    showcase.css('cursor', 'move');
                }
                else{
                    showcase.css('left', $(window).width()/2 +'px');
                    showcase.css('top', $(window).height()/2 +'px');
                    showcase.css('cursor', 'default');
                }
            }
            return false;
        });
        document.getElementById("photosTitle").scrollIntoView();
        showcase.on('dragstart', function(event) { event.preventDefault(); }); // Stop image drag out of page
        if (!isMobile)
            setInterval(timerIncrement, 100);
    }
);

$(document).mousemove(function (event) {
    let cursorY = event.pageY - $(window).scrollTop();
    let elem = document.elementFromPoint(event.pageX, cursorY);
    isMouseOverButtons = !(elem.id === "closeBack" || elem.id === "loadingIconContainer" || elem.id === showcase.attr('id')); // Prevent entering fullscreen when cursor on control buttons
    idle_time = 0;
});

showcase.mousemove(function(event){
    if (showcase.height() > $(window).height() || showcase.width() > $(window).width) {
        showcase.css('cursor', 'move');
        if (move_photo){
            let cursorY = event.pageY - $(window).scrollTop();
            let offsetX = event.pageX - (showcase.position().left + showcase.width()/2);
            let offsetY = cursorY - (showcase.position().top + showcase.height()/2);

            let new_left = showcase.position().left + showcase.width()/2 + offsetX - grab_offsetX;
            let new_top = showcase.position().top + showcase.height()/2 + offsetY - grab_offsetY;

            showcase.css('left', new_left +'px');
            showcase.css('top', new_top +'px');
        }
    }
    else{
        showcase.css('cursor', 'default');
    }
});

showcase.mousedown(function(event){
    move_photo = true;
    let cursorY = event.pageY - $(window).scrollTop();
    grab_offsetX = event.pageX - (showcase.position().left + showcase.width()/2);
    grab_offsetY = cursorY - (showcase.position().top + showcase.height()/2);

    if (isMobile)
        toggleFullscreen();
});

showcase.mouseup(function(){
    move_photo = false;
});

showcase.mouseleave(function(){
    move_photo = false;
});


/*
 * Display selected image in showcase
 * When clicked, display image in full size
 */
function displayBig(elem) {
    isMouseOverButtons = false; // Allow fullscreen when clicking on an image without mouving the mouse
    changeImage($(elem).attr('src'));
    hideTopBar();
    disableFullscreen();
    photoOverlay.fadeIn(500);
    $('body').css('overflow', 'hidden');
}

function getSourceFromThumbnail(source) {
    return source.replace("photos_thumb/", "photos/");
}

function getThumbnailFromSource(source) {
    return source.replace("photos/", "photos_thumb/");
}

/*
 * Hide showcase image
 */
function closeBig() {
    showTopBar();
    disableFullscreen();
    photoOverlay.fadeOut(500);
    $('body').css('overflow', 'auto');
    scrollToShowcaseImage();
}


function scrollToShowcaseImage() {
    let source = showcase.attr('src');
    let image = $("img[src$='" + getThumbnailFromSource(source) + "']");
    if (image !== undefined) {
        image.get(0).scrollIntoView();
    }
}


function enableFullscreen() {
    showcaseButtonContainer.fadeOut(500);
}

function disableFullscreen() {
    showcaseButtonContainer.fadeIn(500);
}

function toggleFullscreen() {
    if (isFullscreen())
        disableFullscreen();
    else
        enableFullscreen();
}

function hideTopBar() {
    headerTop.fadeOut(500);
    sideNav.fadeOut(500);
}

function showTopBar() {
    headerTop.fadeIn(500);
    sideNav.fadeIn(500);
}

function isFullscreen(){
    return showcaseButtonContainer.css("display") === "none";
}


function timerIncrement() {
    if (isMouseOverButtons)
        idle_time = 0;
    else
        idle_time = idle_time+ 1;
    if (idle_time > 10 && !isFullscreen()) { // 1 second
        enableFullscreen();
    } else if (idle_time <= 10 && isFullscreen()){
        disableFullscreen();
    }
}

/*
 * Control images with keyboard arrows
 */
$(document).keydown(function (e) {
    switch (e.keyCode) {
        case 37: // left
            displayNext(-1);
            break;
        case 39: // right
            displayNext(1);
            break;
        case 27: // escape
            closeBig();
            break;
        default:
            return; // exit this handler for other keys
    }
    e.preventDefault(); // prevent the default action (scroll / move caret)
});


/*
 * Display next/last image in showcase. When reaching end/start, loop back to start/end
 */
function displayNext(direction) {
    let currentSrc = showcase.attr('src');
    let photos = document.getElementsByClassName("photo");
    let current = 0;
    for (let i = 0; i < photos.length; i++) {
        if (getSourceFromThumbnail($(photos[i]).attr('src')) === currentSrc) {
            current = i;
        }
    }
    let next = current + direction;
    let nextId = "";
    if (direction > 0) {
        nextId = "#photo-0";
    } else {
        nextId = "#photo-" + (photos.length - 1);
    }
    if (document.getElementById("photo-" + next) != null) {
        nextId = "#photo-" + next;
    }
    let nextSrc = $(nextId).attr('src');
    changeImage(nextSrc);
}

/*
 * Change image source, link and download
 */
function changeImage(thumb) {
    displayLoading();
    showcase.css('display', 'none');
    showcase.on('load', function () {
        hideLoading();
        showcase.css('display', 'block');
        if ($(showcase).width() > $(window).width()){ // prevent display problems on portait devices
            let scale = $(window).width() * 0.9 / $(showcase).width();
            $(showcase).width(scale*$(showcase).width());
            $(showcase).height(scale*$(showcase).height());
        }
    });
    let source = getSourceFromThumbnail(thumb);
    showcase.attr("src", source);
    showcase.css({
        width: 'auto',
        height: '90%',
    });
    showcase.css('left', $(window).width()/2 +'px');
    showcase.css('top', $(window).height()/2 +'px');
    showcaseDownload.attr("href", source);

}


function displayLoading() {
    loading.show();
}

function hideLoading() {
    loading.fadeOut(200);
}