2 # Copyright Anton Khodakivskiy 2012, 2013.
3 # Copyright Simon Lydell 2013, 2014, 2015.
5 # This file is part of VimFx.
7 # VimFx is free software: you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation, either version 3 of the License, or
10 # (at your option) any later version.
12 # VimFx is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with VimFx. If not, see <http://www.gnu.org/licenses/>.
21 # This file contains functions for getting markable elements, and related data,
22 # as well as for creating and inserting markers for markable elements.
24 huffman = require('n-ary-huffman')
25 { Marker } = require('./marker')
26 utils = require('./utils')
28 CONTAINER_ID = 'VimFxMarkersContainer'
30 Element = Ci.nsIDOMElement
31 XULDocument = Ci.nsIDOMXULDocument
33 # For some time we used to return the hints container from `injectHints`, and
34 # use that reference to remove the hints when needed. That’s fine in theory, but
35 # in case anything breaks we might loose that reference and end up with
36 # unremovable hints on the screen. Explicitly looking for an element with the
37 # container ID is more fail-safe.
38 removeHints = (window) ->
39 window.document.getElementById(CONTAINER_ID)?.remove()
41 # Create `Marker`s for every element (represented by a regular object of data
42 # about the element—a “wrapper,” a stand-in for the real element, which is only
43 # accessible in frame scripts) in `wrappers`, and insert them into `window`.
44 injectHints = (window, wrappers, viewport, options) ->
50 for wrapper in wrappers
51 marker = new Marker(wrapper, window.document)
53 when wrapper.parentIndex? then combined
54 when wrapper.semantic then semantic
57 markerMap[wrapper.elementIndex] = marker
59 markers = semantic.concat(unsemantic)
61 return null if markers.length == 0
63 # Each marker gets a unique `z-index`, so that it can be determined if a
64 # marker overlaps another. Put more important markers (higher weight) at the
65 # end, so that they get higher `z-index`, in order not to be overlapped.
67 setZIndexes = (markers) ->
68 markers.sort((a, b) -> a.weight - b.weight)
69 for marker in markers when marker not instanceof huffman.BranchPoint
70 marker.markerElement.style.zIndex = zIndex++
71 # Add `z-index` space for all the children of the marker.
72 zIndex += marker.wrapper.numChildren if marker.wrapper.numChildren?
74 # The `markers` passed to this function have been sorted by `setZIndexes` in
75 # advance, so we can skip sorting in the `huffman.createTree` function.
76 hintChars = options.hint_chars
77 createHuffmanTree = (markers) ->
78 return huffman.createTree(markers, hintChars.length, {sorted: true})
80 # Semantic elements should always get better hints and higher `z-index`:es
81 # than unsemantic ones, even if they are smaller. The former is achieved by
82 # putting the unsemantic elements in their own branch of the huffman tree.
83 if unsemantic.length > 0
84 if markers.length > hintChars.length
85 setZIndexes(unsemantic)
86 subTree = createHuffmanTree(unsemantic)
87 semantic.push(subTree)
89 semantic.push(unsemantic...)
93 tree = createHuffmanTree(semantic)
94 tree.assignCodeWords(hintChars, (marker, hint) -> marker.setHint(hint))
96 # Markers for links with the same href can be combined to use the same hint.
97 # They should all have the same `z-index` (because they all have the same
98 # combined weight), but in case any of them cover another they still get a
99 # unique `z-index` (space for this was added in `setZIndexes`).
100 for marker in combined
101 parent = markerMap[marker.wrapper.parentIndex]
102 marker.markerElement.style.zIndex = parent.markerElement.style.zIndex++
103 marker.setHint(parent.hint)
104 markers.push(combined...)
106 removeHints(window) # Better safe than sorry.
107 container = window.document.createElement('box')
108 container.id = CONTAINER_ID
109 window.gBrowser.mCurrentBrowser.parentNode.appendChild(container)
111 zoom = window.ZoomManager.getZoomForBrowser(window.gBrowser.selectedBrowser)
112 for marker in markers
113 container.appendChild(marker.markerElement)
114 # Must be done after the hints have been inserted into the DOM (see
116 marker.setPosition(viewport, zoom)
121 getMarkableElementsAndViewport = (window, filter) ->
123 clientWidth, clientHeight # Viewport size excluding scrollbars, usually.
124 scrollWidth, scrollHeight
125 } = window.document.documentElement
126 { innerWidth, innerHeight } = window # Viewport size including scrollbars.
127 # We don’t want markers to cover the scrollbars, so we should use
128 # `clientWidth` and `clientHeight`. However, when there are no scrollbars
129 # those might be too small. Then we use `innerWidth` and `innerHeight`.
130 width = if scrollWidth > innerWidth then clientWidth else innerWidth
131 height = if scrollHeight > innerHeight then clientHeight else innerHeight
142 getMarkableElements(window, viewport, wrappers, filter)
143 return {wrappers, viewport}
145 # `filter` is a function that is given every element in every frame of the page.
146 # It should return wrapper objects for markable elements and a falsy value for
147 # all other elements. All returned wrappers are added to `wrappers`. `wrappers`
148 # is modified instead of using return values to avoid array concatenation for
149 # each frame. It might sound expensive to go through _every_ element, but that’s
150 # actually what other methods like using XPath or CSS selectors would need to do
151 # anyway behind the scenes.
152 getMarkableElements = (window, viewport, wrappers, filter, parents = []) ->
153 { document } = window
155 localGetElementShape = getElementShape.bind(null, window, viewport, parents)
156 for element in getElements(document, viewport) when element instanceof Element
157 continue unless wrapper = filter(element, localGetElementShape)
158 wrappers.push(wrapper)
160 for frame in window.frames
161 rect = frame.frameElement.getBoundingClientRect() # Frames only have one.
162 continue unless isInsideViewport(rect, viewport)
164 # Calculate the visible part of the frame, according to the parent.
165 { clientWidth, clientHeight } = frame.document.documentElement
167 left: Math.max(viewport.left - rect.left, 0)
168 top: Math.max(viewport.top - rect.top, 0)
169 right: clientWidth + Math.min(viewport.right - rect.right, 0)
170 bottom: clientHeight + Math.min(viewport.bottom - rect.bottom, 0)
172 # `.getComputedStyle()` may return `null` if the computed style isn’t
173 # availble yet. If so, consider the element not visible.
174 continue unless computedStyle = window.getComputedStyle(frame.frameElement)
177 parseFloat(computedStyle.getPropertyValue('border-left-width')) +
178 parseFloat(computedStyle.getPropertyValue('padding-left'))
180 parseFloat(computedStyle.getPropertyValue('border-top-width')) +
181 parseFloat(computedStyle.getPropertyValue('padding-top'))
183 getMarkableElements(frame, frameViewport, wrappers, filter,
184 parents.concat({ window, offset }))
188 # Returns a suitable set of elements in `document` that could possibly get
190 getElements = (document, viewport) ->
191 # In XUL documents we have to resort to get every single element in the entire
192 # document, because there are lots of complicated “anonymous” elements, which
193 # `windowUtils.nodesFromRect()` does not catch.
194 if document instanceof XULDocument
196 getAllRegular = (element) ->
197 for child in element.getElementsByTagName('*')
199 getAllAnonymous(child)
201 getAllAnonymous = (element) ->
202 for child in document.getAnonymousNodes(element) or []
203 continue unless child instanceof Element
207 getAllRegular(document.documentElement)
209 # In other documents we can use a super-fast Firefox API to get all elements
212 windowUtils = document.defaultView
213 .QueryInterface(Ci.nsIInterfaceRequestor)
214 .getInterface(Ci.nsIDOMWindowUtils)
215 return windowUtils.nodesFromRect(
216 viewport.left, viewport.top, # Rect coordinates, relative to the viewport.
217 # Distances to expand in all directions: top, right, bottom, left.
218 0, viewport.right, viewport.bottom, 0,
219 true, # Unsure what this does. Toggling it seems to make no difference.
220 true # Ensure that the list of matching elements is fully up to date.
223 # Returns the “shape” of `element`:
225 # - `nonCoveredPoint`: The coordinates of the first point of `element` that
226 # isn’t covered by another element (except children of `element`). It also
227 # contains the offset needed to make those coordinates relative to the top
228 # frame, as well as the rectangle that the coordinates occur in.
229 # - `area`: The area of the part of `element` that is inside `viewport`.
231 # Returns `null` if `element` is outside `viewport` or entirely covered by other
233 getElementShape = (window, viewport, parents, element) ->
234 # `element.getClientRects()` returns a list of rectangles, usually just one,
235 # which is identical to the one returned by `element.getBoundingClientRect()`.
236 # However, if `element` is inline and line-wrapped, then it returns one
237 # rectangle for each line, since each line may be of different length, for
238 # example. That allows us to properly add hints to line-wrapped links.
239 rects = element.getClientRects()
242 # The `isInsideViewport` check is not needed in HTML documents, but in XUL
243 # documents (see `getElements()`). However, there seems to be no performance
244 # gain in not running the check in HTML documents, so let’s keep it simple.
245 for rect in rects when isInsideViewport(rect, viewport)
246 visibleRect = adjustRectToViewport(rect, viewport)
247 continue if visibleRect.area == 0
248 totalArea += visibleRect.area
249 visibleRects.push(visibleRect)
251 if visibleRects.length == 0
252 if rects.length == 1 and totalArea == 0
254 if rect.width > 0 or rect.height > 0
255 # If we get here, it means that everything inside `element` is floated
256 # and/or absolutely positioned (and that `element` hasn’t been made to
257 # “contain” the floats). For example, a link in a menu could contain a
258 # span of text floated to the left and an icon floated to the right.
259 # Those are still clickable. Therefore we return the shape of the first
260 # visible child instead. At least in that example, that’s the best bet.
261 for child in element.children
262 shape = getElementShape(window, viewport, parents, child)
263 return shape if shape
266 # Even if `element` has a visible rect, it might be covered by other elements.
267 for visibleRect in visibleRects
268 nonCoveredPoint = getFirstNonCoveredPoint(window, viewport, element,
269 visibleRect, parents)
271 nonCoveredPoint.rect = visibleRect
274 return null unless nonCoveredPoint
277 nonCoveredPoint, area: totalArea
281 MINIMUM_EDGE_DISTANCE = 4
282 isInsideViewport = (rect, viewport) ->
284 rect.left <= viewport.right - MINIMUM_EDGE_DISTANCE and
285 rect.top <= viewport.bottom + MINIMUM_EDGE_DISTANCE and
286 rect.right >= viewport.left + MINIMUM_EDGE_DISTANCE and
287 rect.bottom >= viewport.top - MINIMUM_EDGE_DISTANCE
290 adjustRectToViewport = (rect, viewport) ->
291 # The right and bottom values are subtracted by 1 because
292 # `document.elementFromPoint(right, bottom)` does not return the element
294 left = Math.max(rect.left, viewport.left)
295 right = Math.min(rect.right - 1, viewport.right)
296 top = Math.max(rect.top, viewport.top)
297 bottom = Math.min(rect.bottom - 1, viewport.bottom)
299 # Make sure that `right >= left and bottom >= top`, since we subtracted by 1
301 right = Math.max(right, left)
302 bottom = Math.max(bottom, top)
305 height = bottom - top
306 area = Math.floor(width * height)
309 left, right, top, bottom
314 getFirstNonCoveredPoint = (window, viewport, element, elementRect, parents) ->
315 # Tries a point `(x + dx, y + dy)`. Returns `(x, y)` (and the frame offset)
316 # if it passes the tests. Otherwise it tries to the right of whatever is at
317 # `(x, y)`, `tryRight` times . If nothing succeeds, `false` is returned. `dx`
318 # and `dy` are used to offset the wanted point `(x, y)` while trying (see the
319 # invocations of `tryPoint` below).
320 tryPoint = (x, dx, y, dy, tryRight = 0) ->
321 elementAtPoint = window.document.elementFromPoint(x + dx, y + dy)
322 offset = {left: 0, top: 0}
325 # Ensure that `element`, or a child of `element` (anything inside an `<a>`
326 # is clickable too), really is present at (x,y). Note that this is not 100%
327 # bullet proof: Combinations of CSS can cause this check to fail, even
328 # though `element` isn’t covered. We don’t try to temporarily reset such CSS
329 # because of performance. Instead we rely on that some of the attempts below
331 if element.contains(elementAtPoint) or # Note that `a.contains(a) == true`!
332 (window.document instanceof XULDocument and
333 getClosestNonAnonymousParent(element) == elementAtPoint)
335 # If we’re currently in a frame, there might be something on top of the
336 # frame that covers `element`. Therefore we ensure that the frame really
337 # is present at the point for each parent in `parents`.
338 currentWindow = window
339 for parent in parents by -1
340 offset.left += parent.offset.left
341 offset.top += parent.offset.top
342 elementAtPoint = parent.window.document.elementFromPoint(
343 offset.left + x + dx, offset.top + y + dy
345 unless elementAtPoint == currentWindow.frameElement
348 currentWindow = parent.window
351 return {x, y, offset}
353 return false if elementAtPoint == null or tryRight == 0
354 rect = elementAtPoint.getBoundingClientRect()
355 x = rect.right - offset.left + 1
356 return false if x > viewport.right
357 return tryPoint(x, 0, y, 0, tryRight - 1)
360 # Try the left-middle point, or immediately to the right of a covering element
361 # at that point. If both of those are covered the whole element is considered
362 # to be covered. The reasoning is:
364 # - A marker should show up as near the left edge of its visible area as
365 # possible. Having it appear to the far right (for example) is confusing.
366 # - We can’t try too many times because of performance.
367 # - We used to try left-top first, but if `element` has `border-radius`, the
368 # corners won’t really belong to `element`, so `document.elementFromPoint()`
369 # will return whatever is behind. This will result in missing or
370 # out-of-place markers. The solution is to temporarily add a CSS class that
371 # removes `border-radius`, but that turned out to be rather slow, making it
372 # not worth it. Usually you don’t see the difference between left-top and
373 # left-middle, because links are usually not that high.
374 # - We used to try left-bottom as well, but that is so rare that it’s not
377 # It is safer to try points at least one pixel into the element from the
378 # edges, hence the `+1`.
379 { left, top, bottom, height } = elementRect
380 nonCoveredPoint = tryPoint(left, +1, Math.floor(top + height / 2), 0, 1)
382 return nonCoveredPoint
384 # In XUL documents there are “anonymous” elements, whose node names start with
385 # `xul:` or `html:`. These are never returned by `document.elementFromPoint` but
386 # their closest non-anonymous parents are.
387 getClosestNonAnonymousParent = (element) ->
388 element = element.parentNode while element.prefix?
394 getMarkableElementsAndViewport