diff options
Diffstat (limited to 'content_scripts')
| -rw-r--r-- | content_scripts/scroller.coffee | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/content_scripts/scroller.coffee b/content_scripts/scroller.coffee index 2f69fc7d..fdfb7ddc 100644 --- a/content_scripts/scroller.coffee +++ b/content_scripts/scroller.coffee @@ -67,7 +67,7 @@ shouldScroll = (element, direction) -> # Instead, we scroll the element by 1 or -1 and see if it moved (then put it back). :factor is the factor by # which :scrollBy and :scrollTo will later scale the scroll amount. :factor can be negative, so we need it # here in order to decide whether we should test a forward scroll or a backward scroll. -# Bug verified in Chrome 38.0.2125.104. +# Bug last verified in Chrome 38.0.2125.104. doesScroll = (element, direction, amount, factor) -> # amount is treated as a relative amount, which is correct for relative scrolls. For absolute scrolls (only # gg, G, and friends), amount can be either a string ("max" or "viewSize") or zero. In the former case, @@ -84,6 +84,19 @@ findScrollableElement = (element, direction, amount, factor) -> element = element.parentElement || document.body element +# On some pages, document.body is not scrollable. Here, we search the document for the largest visible +# element which does scroll vertically. This is used to initialize activatedElement. See #1358. +firstScrollableElement = (element=document.body) -> + if doesScroll(element, "y", 1, 1) or doesScroll(element, "y", -1, 1) + element + else + children = ({element: child, rect: DomUtils.getVisibleClientRect(child)} for child in element.children) + children = children.filter (child) -> child.rect # Filter out non-visible elements. + children.map (child) -> child.area = child.rect.width * child.rect.height + for child in children.sort((a,b) -> b.area - a.area) # Largest to smallest by visible area. + return ele if ele = firstScrollableElement child.element + null + checkVisibility = (element) -> # If the activated element has been scrolled completely offscreen, then subsequent changes in its scroll # position will not provide any more visual feedback to the user. Therefore, we deactivate it so that @@ -206,7 +219,7 @@ Scroller = window.scrollBy(0, amount) return - activatedElement ||= document.body + activatedElement ||= firstScrollableElement() return unless activatedElement # Avoid the expensive scroll calculation if it will not be used. This reduces costs during smooth, @@ -217,8 +230,8 @@ Scroller = CoreScroller.scroll element, direction, elementAmount scrollTo: (direction, pos) -> - return unless document.body or activatedElement - activatedElement ||= document.body + activatedElement ||= firstScrollableElement() + return unless activatedElement element = findScrollableElement activatedElement, direction, pos, 1 amount = getDimension(element,direction,pos) - element[scrollProperties[direction].axisName] |