ecomp-portal-FE/client/bower_components/jqTree/src/scroll_handler.coffee

   1 $ = jQuery
   2
   3
   4 class ScrollHandler
   5     constructor: (tree_widget) ->
   6         @tree_widget = tree_widget
   7         @previous_top = -1
   8         @is_initialized = false
   9
  10     _initScrollParent: ->
  11         getParentWithOverflow = =>
  12             css_values = ['overflow', 'overflow-y']
  13
  14             hasOverFlow = (el) ->
  15                 for css_value in css_values
  16                     if $.css(el, css_value) in ['auto', 'scroll']
  17                         return true
  18
  19                 return false
  20
  21             if hasOverFlow(@tree_widget.$el[0])
  22                 return @tree_widget.$el
  23
  24             for el in @tree_widget.$el.parents()
  25                 if hasOverFlow(el)
  26                     return $(el)
  27
  28             return null
  29
  30         setDocumentAsScrollParent = =>
  31             @scroll_parent_top = 0
  32             @$scroll_parent = null
  33
  34         if @tree_widget.$el.css('position') == 'fixed'
  35             setDocumentAsScrollParent()
  36
  37         $scroll_parent = getParentWithOverflow()
  38
  39         if $scroll_parent and $scroll_parent.length and $scroll_parent[0].tagName != 'HTML'
  40             @$scroll_parent = $scroll_parent
  41             @scroll_parent_top = @$scroll_parent.offset().top
  42         else
  43             setDocumentAsScrollParent()
  44
  45         @is_initialized = true
  46
  47     _ensureInit: ->
  48         if not @is_initialized
  49             @_initScrollParent()
  50
  51     checkScrolling: ->
  52         @_ensureInit()
  53
  54         hovered_area = @tree_widget.dnd_handler.hovered_area
  55
  56         if hovered_area and hovered_area.top != @previous_top
  57             @previous_top = hovered_area.top
  58
  59             if @$scroll_parent
  60                 @_handleScrollingWithScrollParent(hovered_area)
  61             else
  62                 @_handleScrollingWithDocument(hovered_area)
  63
  64     _handleScrollingWithScrollParent: (area) ->
  65         distance_bottom = @scroll_parent_top + @$scroll_parent[0].offsetHeight - area.bottom
  66
  67         if distance_bottom < 20
  68             @$scroll_parent[0].scrollTop += 20
  69             @tree_widget.refreshHitAreas()
  70             @previous_top = -1
  71         else if (area.top - @scroll_parent_top) < 20
  72             @$scroll_parent[0].scrollTop -= 20
  73             @tree_widget.refreshHitAreas()
  74             @previous_top = -1
  75
  76     _handleScrollingWithDocument: (area) ->
  77         distance_top = area.top - $(document).scrollTop()
  78
  79         if distance_top < 20
  80             $(document).scrollTop($(document).scrollTop() - 20)
  81         else if $(window).height() - (area.bottom - $(document).scrollTop()) < 20
  82             $(document).scrollTop($(document).scrollTop() + 20)
  83
  84     scrollTo: (top) ->
  85         @_ensureInit()
  86
  87         if @$scroll_parent
  88             @$scroll_parent[0].scrollTop = top
  89         else
  90             tree_top = @tree_widget.$el.offset().top
  91             $(document).scrollTop(top + tree_top)
  92
  93     isScrolledIntoView: (element) ->
  94         @_ensureInit()
  95
  96         $element = $(element)
  97
  98         if @$scroll_parent
  99             view_top = 0
 100             view_bottom = @$scroll_parent.height()
 101
 102             element_top = $element.offset().top - @scroll_parent_top
 103             element_bottom = element_top + $element.height()
 104         else
 105             view_top = $(window).scrollTop()
 106             view_bottom = view_top + $(window).height()
 107
 108             element_top = $element.offset().top
 109             element_bottom = element_top + $element.height()
 110
 111         return (element_bottom <= view_bottom) and (element_top >= view_top)
 112
 113
 114 module.exports = ScrollHandler