public Drag(AppRect dragBounds, Direction direction, DragLength dragLength)
{
this.dragBounds = dragBounds;
dragDirection = direction;
this.dragLength = dragLength;
SetDragForBounds(dragDirection, dragLength);
}
private void OnMouseMove(MouseEventArgs e)
{
if (IsDragging == false || SkipEventHandling(e))
{
return;
}
try
{
ScreenPoint = MouseInternal.ScreenPosition;
if (_thresholdExceeded)
{
OnDragMove();
}
else
{
if (DragLength.IsGreaterThanOrClose(Threshold) == false)
{
return;
}
_thresholdExceeded = true;
OnDragStarted();
}
}
finally
{
PostEventHandling(e);
}
}
void SetDragForBounds(Direction direction, DragLength dragLength)
{
// percentage of bounds to scroll centered in element
float scrollPercentage;
switch (dragLength)
{
case DragLength.Long:
scrollPercentage = 0.8f;
break;
case DragLength.Medium:
scrollPercentage = 0.5f;
break;
default:
scrollPercentage = 0.2f;
break;
}
if (direction == Direction.LeftToRight)
{
yStart = dragBounds.CenterY;
yEnd = dragBounds.CenterY;
float xDisplacement = (dragBounds.CenterX + (dragBounds.Width / 2)) - dragBounds.X;
float insetForScroll = (xDisplacement - (xDisplacement * scrollPercentage)) / 2;
xStart = dragBounds.X + insetForScroll;
xEnd = (dragBounds.CenterX + (dragBounds.Width / 2)) - insetForScroll;
}
else if (direction == Direction.RightToLeft)
{
yStart = dragBounds.CenterY;
yEnd = dragBounds.CenterY;
float xDisplacement = (dragBounds.CenterX + (dragBounds.Width / 2)) - dragBounds.X;
float insetForScroll = (xDisplacement - (xDisplacement * scrollPercentage)) / 2;
xStart = (dragBounds.CenterX + (dragBounds.Width / 2)) - insetForScroll;
xEnd = dragBounds.X + insetForScroll;
}
else if (direction == Direction.TopToBottom)
{
xStart = dragBounds.CenterX;
xEnd = dragBounds.CenterX;
float yDisplacement = (dragBounds.CenterY + (dragBounds.Height / 2)) - dragBounds.Y;
float insetForScroll = (yDisplacement - (yDisplacement * scrollPercentage)) / 2;
yStart = dragBounds.Y + insetForScroll;
yEnd = (dragBounds.CenterY + (dragBounds.Height / 2)) - insetForScroll;
}
else if (direction == Direction.BottomToTop)
{
xStart = dragBounds.CenterX;
xEnd = dragBounds.CenterX;
float yDisplacement = (dragBounds.CenterY + (dragBounds.Height / 2)) - dragBounds.Y;
float insetForScroll = (yDisplacement - (yDisplacement * scrollPercentage)) / 2;
yStart = (dragBounds.CenterY + (dragBounds.Height / 2)) - insetForScroll;
yEnd = dragBounds.Y + insetForScroll;
}
}
