diff options
| -rw-r--r-- | content_scripts/scroller.coffee | 54 |
1 files changed, 26 insertions, 28 deletions
diff --git a/content_scripts/scroller.coffee b/content_scripts/scroller.coffee index ecb739ec..e418a930 100644 --- a/content_scripts/scroller.coffee +++ b/content_scripts/scroller.coffee @@ -3,7 +3,6 @@ # input elements. This mechanism allows us to decide whether to scroll a div or to scroll the whole document. # activatedElement = null -settings = null scrollProperties = x: { @@ -83,38 +82,37 @@ checkVisibility = (element) -> # continues scrolling at least until its corresponding keyup event is received. We never initiate a new # animator on keyboard repeat. -# Scroll by a relative amount (a number) in some direction, possibly smoothly. -doScrollBy = do -> - # This is logical time. Time is advanced each time an animator is activated, and on each keyup event. - time = 0 - lastEvent = null - keyHandler = null - keyIsDown = false - - (element, direction, amount) -> +CoreScroller = + init: (frontendSettings) -> + @settings = frontendSettings + @time = 0 + @lastEvent = null + @keyIsDown = false + handlerStack.push + keydown: (event) => + @keyIsDown = true + @lastEvent = event + keyup: => + @keyIsDown = false + @time += 1 + + # Scroll element by a relative amount (a number) in some direction. + scroll: (element, direction, amount) -> return unless amount - keyHandler ?= handlerStack.push - keydown: -> - keyIsDown = true unless event.repeat - lastEvent = event - keyup: -> - keyIsDown = false - time += 1 - - unless settings.get "smoothScroll" + unless @settings.get "smoothScroll" # Jump scrolling. performScroll element, direction, amount checkVisibility element return # We don't activate new animators on keyboard repeats. - return if lastEvent?.repeat + return if @lastEvent?.repeat - activationTime = ++time + activationTime = ++@time - isKeyStillDown = -> - time == activationTime and keyIsDown + isMyKeyStillDown = => + @time == activationTime and @keyIsDown # Store amount's sign and make amount positive; the logic is clearer when amount is positive. sign = Math.sign amount @@ -149,14 +147,14 @@ doScrollBy = do -> # The constants in the duration calculation, above, are chosen to provide reasonable scroll speeds for # scrolls resulting from distinct keypresses. For continuous scrolls (where the key remains depressed), # some scrolls are too slow, and others too fast. Here, we compensate a bit. - if isKeyStillDown() and 50 <= totalElapsed and 0.5 <= calibration <= 1.6 + if isMyKeyStillDown() and 50 <= totalElapsed and 0.5 <= calibration <= 1.6 calibration *= 1.05 if 1.05 * calibration * amount <= 150 # Speed up slow scrolls. calibration *= 0.95 if 150 <= 0.95 * calibration * amount # Slow down fast scrolls. # Calculate the initial delta, rounding up to ensure progress. Then, adjust delta to account for the # current scroll state. delta = Math.ceil amount * (elapsed / duration) * calibration - delta = if isKeyStillDown() then delta else Math.max 0, Math.min delta, amount - totalDelta + delta = if isMyKeyStillDown() then delta else Math.max 0, Math.min delta, amount - totalDelta if delta and performScroll element, direction, sign * delta totalDelta += delta @@ -169,8 +167,8 @@ doScrollBy = do -> Scroller = init: (frontendSettings) -> - settings = frontendSettings handlerStack.push DOMActivate: -> activatedElement = event.target + CoreScroller.init frontendSettings # scroll the active element in :direction by :amount * :factor. # :factor is needed because :amount can take on string values, which scrollBy converts to element dimensions. @@ -188,7 +186,7 @@ Scroller = element = findScrollableElement activatedElement, direction, amount, factor elementAmount = factor * getDimension element, direction, amount - doScrollBy element, direction, elementAmount + CoreScroller.scroll element, direction, elementAmount scrollTo: (direction, pos) -> return unless document.body or activatedElement @@ -196,7 +194,7 @@ Scroller = element = findScrollableElement activatedElement, direction, pos amount = getDimension(element,direction,pos) - element[scrollProperties[direction].axisName] - doScrollBy element, direction, amount + CoreScroller.scroll element, direction, amount root = exports ? window root.Scroller = Scroller |