public override void PrepareSelectionAnchor(SelectionAnchorCaret caret)
{
if (caret.Fragment == null)
{
Debug.Assert(Chunk.SequenceNumber == caret.Anchor?.Chunk.SequenceNumber);
// find fragment at anchor offset
var offset = caret.Anchor.Offset;
int index = ViewContent.TextLayer.FindInRange(FirstFragmentIndex, LastFragmentIndex, f => ((TextFragment)f).Offset <= offset ? -1 : 1) - 1;
caret.Fragment = ViewContent.TextLayer.Items[index];
}
var fragment = caret.Fragment;
var txtFrag = (TextFragment)fragment;
var txtFragOffset = txtFrag.Offset;
var txtFragLen = txtFrag.Length;
var charWidth = fragment.View.Content.CharWidth;
var fragLoc = fragment.Bounds.Location;
var toTheEnd = false;
if (caret.Anchor == null)
{
Debug.Assert(caret.Fragment?.IsSelectable == true);
Debug.Assert(Chunk == caret.Fragment.Source.BaseChunk);
caret.Anchor = new SelectionAnchor()
{
Chunk = Chunk
};
if (fragment.View.Mouse.Position.Y > fragment.Bounds.Bottom)
{
caret.Anchor.Offset = fragment.IsTrailing ? txtFrag.Data.Length : txtFragLen + txtFragOffset;
toTheEnd = true;
}
else
{
double pos = fragment.View.Mouse.Position.X + charWidth / 2.0;
caret.Anchor.Offset = Math.Min(txtFragLen, Math.Max(0, (int)((pos - fragLoc.X) / charWidth))) + txtFragOffset;
}
}
else
{
if (caret.Anchor.Offset >= Chunk.Payload.Length)
{
toTheEnd = true;
}
}
caret.Bounds = new Rect(
toTheEnd ? fragment.Bounds.Right : fragLoc.X + (caret.Anchor.Offset - txtFragOffset) * charWidth,
fragLoc.Y,
charWidth,
fragment.Bounds.Height);
}
/// <summary> /// Method should resolve missing properties <see cref="SelectionAnchorCaret.Fragment"/> or <see cref="SelectionAnchorCaret.Anchor"/> and update <see cref="SelectionAnchorCaret.Bounds"/>. /// </summary> public virtual void PrepareSelectionAnchor(SelectionAnchorCaret caret) => throw new NotImplementedException();