Commit fbbbe95e authored by Hiroyuki Ikezoe's avatar Hiroyuki Ikezoe
Browse files

Bug 1766805 - Give the proper destination to GetSnapPointForDestination for... 

Bug 1766805 - Give the proper destination to GetSnapPointForDestination for ScrollUnit::WHOLE on the main-thread. r=botond

Now the proper destination is same as what we do for ScrollUnit::WHOLE [1].

With the proper points we no longer need special handlings in
CalcSnapPoints::AddEdge for ScrollUnit::WHOLE. In my sense the special handling
wasn't necessary though.

[1] https://searchfox.org/mozilla-central/rev/dc09246dfbfd8dafeb6d55ebee18a6294d525443/gfx/layers/apz/src/AsyncPanZoomController.cpp#2105-2112

Differential Revision: https://phabricator.services.mozilla.com/D145190
parent 9e02f38a

layout/generic/ScrollSnap.cpp

+9 −22
Original line number Diff line number Diff line
@@ -118,12 +118,7 @@ void CalcSnapPoints::AddEdge(nscoord aEdge, nscoord aDestination, 
      // The scroll direction is neutral - will not hit a snap point.

      return;

    }

    // ScrollUnit::WHOLE indicates that we are navigating to "home" or

    // "end".  In this case, we will always select the first or last snap point

    // regardless of the direction of the scroll.  Otherwise, we will select

    // scroll snapping points only in the direction specified by

    // aScrollingDirection.

    if (mUnit != ScrollUnit::WHOLE) {



    // Direction of the edge from the current position (before scrolling) in

    // the direction of scrolling

    nscoord direction = (aEdge - aStartPos) * aScrollingDirection;
@@ -132,7 +127,6 @@ void CalcSnapPoints::AddEdge(nscoord aEdge, nscoord aDestination, 
      return;

    }

  }

  }

  if (!*aEdgeFound) {

    *aBestEdge = aEdge;

    *aEdgeFound = true;
@@ -162,7 +156,8 @@ void CalcSnapPoints::AddEdge(nscoord aEdge, nscoord aDestination, 
    }

  };



  if (mUnit == ScrollUnit::DEVICE_PIXELS || mUnit == ScrollUnit::LINES) {

  if (mUnit == ScrollUnit::DEVICE_PIXELS || mUnit == ScrollUnit::LINES ||

      mUnit == ScrollUnit::WHOLE) {

    nscoord distance = std::abs(aEdge - aDestination);

    updateBestEdges(

        distance < std::abs(*aBestEdge - aDestination),
@@ -191,14 +186,6 @@ void CalcSnapPoints::AddEdge(nscoord aEdge, nscoord aDestination, 
    if (overshoot > 0) {

      updateBestEdges(overshoot < curOvershoot, overshoot < secondOvershoot);

    }

  } else if (mUnit == ScrollUnit::WHOLE) {

    // the edge closest to the top/bottom/left/right is used, depending on

    // scrolling direction

    if (aScrollingDirection > 0) {

      updateBestEdges(aEdge > *aBestEdge, aEdge > *aSecondBestEdge);

    } else if (aScrollingDirection < 0) {

      updateBestEdges(aEdge < *aBestEdge, aEdge < *aSecondBestEdge);

    }

  } else {

    NS_ERROR("Invalid scroll mode");

    return;

layout/generic/nsGfxScrollFrame.cpp

+13 −7
Original line number Diff line number Diff line
@@ -4758,11 +4758,18 @@ nsRect ScrollFrameHelper::GetVisualOptimalViewingRect() const { 
  return rect;

}



static void AdjustForWholeDelta(int32_t aDelta, nscoord* aCoord) {

  if (aDelta < 0) {

    *aCoord = nscoord_MIN;

  } else if (aDelta > 0) {

    *aCoord = nscoord_MAX;

static void AdjustDestinationForWholeDelta(const nsIntPoint& aDelta,

                                           const nsRect& aScrollRange,

                                           nsPoint& aPoint) {

  if (aDelta.x < 0) {

    aPoint.x = aScrollRange.X();

  } else if (aDelta.x > 0) {

    aPoint.x = aScrollRange.XMost();

  }

  if (aDelta.y < 0) {

    aPoint.y = aScrollRange.Y();

  } else if (aDelta.y > 0) {

    aPoint.y = aScrollRange.YMost();

  }

}
@@ -4869,8 +4876,7 @@ void ScrollFrameHelper::ScrollBy(nsIntPoint aDelta, ScrollUnit aUnit, 
        break;

      } else {

        nsPoint pos = GetScrollPosition();

        AdjustForWholeDelta(aDelta.x, &pos.x);

        AdjustForWholeDelta(aDelta.y, &pos.y);

        AdjustDestinationForWholeDelta(aDelta, GetLayoutScrollRange(), pos);

        if (aSnap == nsIScrollableFrame::ENABLE_SNAP) {

          GetSnapPointForDestination(aUnit, mDestination, pos);

        }