extension/packages/marker.coffee

   1 { getPref } = require 'prefs'
   2 utils       = require 'utils'
   3
   4 { interfaces: Ci } = Components
   5
   6 XPathResult        = Ci.nsIDOMXPathResult
   7
   8 # All elements that have one or more of the following properties
   9 # qualify for their own marker in hints mode
  10 MARKABLE_ELEMENT_PROPERTIES = [
  11   "@tabindex"
  12   "@onclick"
  13   "@onmousedown"
  14   "@onmouseup"
  15   "@oncommand"
  16   "@role='link'"
  17   "@role='button'"
  18   "contains(@class, 'button')"
  19   "@contenteditable='' or translate(@contenteditable, 'TRUE', 'true')='true'"
  20 ]
  21
  22 # All the following elements qualify for their own marker in hints mode
  23 MARKABLE_ELEMENTS = [
  24   "a"
  25   "iframe"
  26   "area[@href]"
  27   "textarea"
  28   "button"
  29   "select"
  30   "input[not(@type='hidden' or @disabled or @readonly)]"
  31   "embed"
  32   "object"
  33 ]
  34
  35 # Marker class wraps the markable element and provides
  36 # methods to manipulate the markers
  37 class Marker
  38   # Creates the marker DOM node
  39   constructor: (@element) ->
  40     document = @element.ownerDocument
  41     window = document.defaultView
  42     @markerElement = document.createElement('div')
  43     @markerElement.className = 'VimFxReset VimFxHintMarker'
  44
  45   # Shows the marker
  46   show: -> @markerElement.className = 'VimFxReset VimFxHintMarker'
  47
  48   # Hides the marker
  49   hide: -> @markerElement.className = 'VimFxReset VimFxHiddenHintMarker'
  50
  51   # Positions the marker on the page. The positioning is absulute
  52   setPosition: (rect) ->
  53     @markerElement.style.left = rect.left + 'px'
  54     @markerElement.style.top  = rect.top  + 'px'
  55
  56   # Assigns hint string to the marker
  57   setHint: (@hintChars) ->
  58     # number of hint chars that have been matched so far
  59     @enteredHintChars = ''
  60
  61     document = @element.ownerDocument
  62
  63     while @markerElement.hasChildNodes()
  64       @markerElement.removeChild(@markedElement.firstChild)
  65
  66     fragment = document.createDocumentFragment()
  67     for char in @hintChars
  68       span = document.createElement('span')
  69       span.className = 'VimFxReset'
  70       span.textContent = char.toUpperCase()
  71
  72       fragment.appendChild(span)
  73
  74     @markerElement.appendChild(fragment)
  75
  76   # Add another char to the `enteredHintString`,
  77   # see if it still matches `hintString`, apply classes to
  78   # the distinct hint characters and show/hide marker when
  79   # the entered string partially (not) matches the hint string
  80   matchHintChar: (char) ->
  81     # Handle backspace key by removing a previously entered hint char
  82     # and resetting its class
  83     if char == 'Backspace'
  84       if @enteredHintChars.length > 0
  85         @enteredHintChars = @enteredHintChars[0...-1]
  86         @markerElement.children[@enteredHintChars.length]?.className = 'VimFxReset'
  87     # Otherwise append hint char and change hint class
  88     else
  89       @markerElement.children[@enteredHintChars.length]?.className = 'VimFxReset VimFxCharMatch'
  90       @enteredHintChars += char.toLowerCase()
  91
  92     # If entered hint chars no longer partially match the hint chars
  93     # then hide the marker. Othersie show it back
  94     if @hintChars.search(@enteredHintChars) == 0 then @show() else @hide()
  95
  96   # Checks if the marker will be matched if the next character entered is `char`
  97   willMatch: (char) ->
  98     char == 'Backspace' or @hintChars.search(@enteredHintChars + char.toLowerCase()) == 0
  99
 100   # Checks if enterd hint chars completely match the hint chars
 101   isMatched: ->
 102     return @hintChars == @enteredHintChars
 103
 104
 105 # Selects all markable elements on the page, creates markers
 106 # for each of them The markers are then positioned on the page
 107 #
 108 # The array of markers is returned
 109 Marker.createMarkers = (document, startIndex) ->
 110   hintChars = utils.getHintChars()
 111
 112   set = getMarkableElements(document)
 113   markers = []
 114
 115   elements = []
 116   for i in [0...set.snapshotLength] by 1
 117     e = set.snapshotItem(i)
 118     if rect = getElementRect(e)
 119       elements.push([e, rect])
 120
 121   elements.sort ([e1, r1], [e2, r2]) ->
 122     # <a> links should always be on the top. E.g. not links should go down
 123     e1tagName = e1.tagName.toLowerCase()
 124     e2tagName = e2.tagName.toLowerCase()
 125     if e1tagName == 'a' and e2tagName != 'a'
 126       return 1
 127     else if e1tagName != 'a' and e2tagName == 'a'
 128       return -1
 129     else if r1.area < r2.area
 130       return -1
 131     else if r1.area > r2.area
 132       return 1
 133     else
 134       return 0
 135
 136   # start from the end because the list is sorted in ascending order
 137   j = elements.length + startIndex - 1
 138   for [element, rect] in elements
 139     # Get a hint for an element
 140     hint = indexToHint(--j, hintChars)
 141     marker = new Marker(element)
 142     marker.setPosition(rect)
 143     marker.setHint(hint)
 144     markers.push(marker)
 145
 146   return markers
 147
 148 # Function generator that creates a function that
 149 # returns hint string for supplied numeric index.
 150 indexToHint = do ->
 151   # Helper function that returns a permutation number `i`
 152   # of some of the characters in the `chars` agrument
 153   f = (i, chars) ->
 154     return '' if i < 0
 155
 156     n = chars.length
 157     l = Math.floor(i / n); k = i % n
 158
 159     return f(l - 1, chars) + chars[k]
 160
 161   return (i, chars) ->
 162     # split the characters into two groups:
 163     #
 164     # *  left chars are used for the head
 165     # *  right chars are used to build the tail
 166     left = chars[...chars.length / 3]
 167     right = chars[chars.length / 3...]
 168
 169     n = Math.floor(i / left.length)
 170     m = i % left.length
 171     return f(n - 1, right) + left[m]
 172
 173
 174 # Returns elements that qualify for hint markers in hints mode.
 175 # Generates and memoizes an XPath query internally
 176 getMarkableElements = do ->
 177   # Some preparations done on startup
 178   elements = Array.concat \
 179     MARKABLE_ELEMENTS,
 180     ["*[#{ MARKABLE_ELEMENT_PROPERTIES.join(' or ') }]"]
 181
 182   xpath = elements.reduce((m, rule) ->
 183     m.concat(["//#{ rule }", "//xhtml:#{ rule }"])
 184   , []).join(' | ')
 185
 186   namespaceResolver = (namespace) ->
 187     if namespace == 'xhtml' then 'http://www.w3.org/1999/xhtml' else null
 188
 189   # The actual function that will return the desired elements
 190   return (document, resultType = XPathResult.ORDERED_NODE_SNAPSHOT_TYPE) ->
 191     document.evaluate(xpath, document.documentElement, namespaceResolver, resultType, null)
 192
 193 # Checks if the given TextRectangle object qualifies
 194 # for its own Marker with respect to the `window` object
 195 isRectOk = (rect, window) ->
 196   rect.width > 2 and rect.height > 2 and \
 197   rect.top > -2 and rect.left > -2 and \
 198   rect.top < window.innerHeight - 2 and \
 199   rect.left < window.innerWidth - 2
 200
 201 # Will scan through `element.getClientRects()` and look for
 202 # the first visible rectange. If there are no visible rectangles, then
 203 # will look at the children of the markable node.
 204 #
 205 # The logic has been copied over from Vimiun
 206 getElementRect = (element) ->
 207   document = element.ownerDocument
 208   window   = document.defaultView
 209   docElem  = document.documentElement
 210   body     = document.body
 211
 212   clientTop  = docElem.clientTop  || body?.clientTop  || 0
 213   clientLeft = docElem.clientLeft || body?.clientLeft || 0
 214   scrollTop  = window.pageYOffset || docElem.scrollTop
 215   scrollLeft = window.pageXOffset || docElem.scrollLeft
 216
 217   clientRect = element.getBoundingClientRect()
 218   rects = [rect for rect in element.getClientRects()]
 219   rects.push(clientRect)
 220
 221   for rect in rects
 222     if isRectOk(rect, window)
 223       return {
 224         top:    rect.top  + scrollTop  - clientTop
 225         left:   rect.left + scrollLeft - clientLeft
 226         width:  rect.width
 227         height: rect.height
 228         area:   clientRect.width * clientRect.height
 229       }
 230
 231   # If the element has 0 dimentions then check what's inside.
 232   # Floated or absolutely positioned elements are of particular interest
 233   for rect in rects
 234     if rect.width == 0 or rect.height == 0
 235       for childElement in element.children
 236         if computedStyle = window.getComputedStyle(childElement, null)
 237           if computedStyle.getPropertyValue('float') != 'none' or \
 238              computedStyle.getPropertyValue('position') == 'absolute'
 239
 240             return childRect if childRect = getElementRect(childElement)
 241
 242   return undefined
 243
 244 exports.Marker = Marker