jellyfin-web/dashboard-ui/bower_components/emby-webcomponents/scrollhelper.js

define(["focusManager", "dom", "scrollStyles"], function(focusManager, dom) {
    "use strict";

    function getBoundingClientRect(elem) {
        return elem.getBoundingClientRect ? elem.getBoundingClientRect() : {
            top: 0,
            left: 0
        }
    }

    function getPosition(scrollContainer, item, horizontal) {
        var slideeOffset = getBoundingClientRect(scrollContainer),
            itemOffset = getBoundingClientRect(item),
            offset = horizontal ? itemOffset.left - slideeOffset.left : itemOffset.top - slideeOffset.top,
            size = horizontal ? itemOffset.width : itemOffset.height;
        size || 0 === size || (size = item[horizontal ? "offsetWidth" : "offsetHeight"]);
        var currentStart = horizontal ? scrollContainer.scrollLeft : scrollContainer.scrollTop;
        offset += currentStart;
        var frameSize = horizontal ? scrollContainer.offsetWidth : scrollContainer.offsetHeight,
            currentEnd = currentStart + frameSize;
        return {
            start: offset,
            center: offset - frameSize / 2 + size / 2,
            end: offset - frameSize + size,
            size: size,
            isVisible: offset >= currentStart && offset + size <= currentEnd
        }
    }

    function toCenter(container, elem, horizontal, skipWhenVisible) {
        var pos = getPosition(container, elem, horizontal);
        skipWhenVisible && pos.isVisible || (container.scrollTo ? horizontal ? container.scrollTo(pos.center, 0) : container.scrollTo(0, pos.center) : horizontal ? container.scrollLeft = Math.round(pos.center) : container.scrollTop = Math.round(pos.center))
    }

    function toStart(container, elem, horizontal, skipWhenVisible) {
        var pos = getPosition(container, elem, horizontal);
        skipWhenVisible && pos.isVisible || (container.scrollTo ? horizontal ? container.scrollTo(pos.start, 0) : container.scrollTo(0, pos.start) : horizontal ? container.scrollLeft = Math.round(pos.start) : container.scrollTop = Math.round(pos.start))
    }

    function centerOnFocus(e, scrollSlider, horizontal) {
        var focused = focusManager.focusableParent(e.target);
        focused && toCenter(scrollSlider, focused, horizontal)
    }

    function centerOnFocusHorizontal(e) {
        centerOnFocus(e, this, !0)
    }

    function centerOnFocusVertical(e) {
        centerOnFocus(e, this, !1)
    }
    return {
        getPosition: getPosition,
        centerFocus: {
            on: function(element, horizontal) {
                horizontal ? dom.addEventListener(element, "focus", centerOnFocusHorizontal, {
                    capture: !0,
                    passive: !0
                }) : dom.addEventListener(element, "focus", centerOnFocusVertical, {
                    capture: !0,
                    passive: !0
                })
            },
            off: function(element, horizontal) {
                horizontal ? dom.removeEventListener(element, "focus", centerOnFocusHorizontal, {
                    capture: !0,
                    passive: !0
                }) : dom.removeEventListener(element, "focus", centerOnFocusVertical, {
                    capture: !0,
                    passive: !0
                })
            }
        },
        toCenter: toCenter,
        toStart: toStart
    }
});