TextCaret IVisualLine <TextCaret> .FindClosestTo(double xPosition)
{
var container = GetContainer();
var lineBounds = GetCachedLineBounds(container);
double DistanceTo(TextCaret caretToMeasure)
=> Math.Abs(xPosition - TextCaretMeasurerHelper.Measure(caretToMeasure).Left);
var caret = TextCaret.FromOffset(container.Content, container.Offset.GraphemeOffset);
var closest =
(caret : caret,
index : 0,
distance : DistanceTo(caret)
);
for (int i = 1; i < lineBounds.Length; i++)
{
caret = caret.GetNextPosition();
var diff = DistanceTo(caret);
if (diff <= closest.distance)
{
closest = (caret, i, diff);
}
else
{
// we're getting bigger
break;
}
}
return(closest.caret);
}
private double UpdateMovementMode(CaretMovementMode movementMode, TextCaret caret)
{
switch (movementMode.CurrentMode)
{
case CaretMovementMode.Mode.None:
var position = TextCaretMeasurerHelper.Measure(caret).Left;
movementMode.SetModeToPosition(position);
return(position);
case CaretMovementMode.Mode.Position:
return(movementMode.Position);
case CaretMovementMode.Mode.Home:
return(0);
case CaretMovementMode.Mode.End:
return(double.MaxValue);
default:
throw new ArgumentOutOfRangeException();
}
}