Pony.fm/resources/scripts/app/directives/scroll-recorder.coffee
2021-02-14 04:23:12 +00:00

44 lines
1.7 KiB
CoffeeScript

# Pony.fm - A community for pony fan music.
# Copyright (C) 2015 Feld0
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
module.exports = angular.module('ponyfm').directive 'pfmScrollRecorder', () ->
(scope, element, attrs) ->
timeout = null
onScroll = null
lastInView = null
element.scroll (e) ->
(window.clearTimeout timeout) if timeout
timeout = window.setTimeout (-> onScroll e), 500
onScroll = (e) -> scope.safeApply ->
items = element.find 'li:not(.empty)'
itemHeight = (items.eq 0).height()
itemsArray = items.get()
elementViewTop = element.offset().top
elementViewBottom = elementViewTop + element.height()
for i in [itemsArray.length - 1..0]
listItem = $ itemsArray[i]
listItemTop = listItem.offset().top + itemHeight
isInView = listItemTop > elementViewTop && listItemTop < elementViewBottom
if isInView
lastInView = listItem
break
scope.$emit 'element-in-view', angular.element(lastInView).scope()