/// <summary>
/// Validates the visual column of the caret using the specified visual line.
/// The visual line must contain the caret offset.
/// </summary>
void RevalidateVisualColumn(VisualLine visualLine)
{
if (visualLine == null)
throw new ArgumentNullException("visualLine");
// mark column as validated
visualColumnValid = true;
int caretOffset = textView.Document.GetOffset(position.Location);
int firstDocumentLineOffset = visualLine.FirstDocumentLine.Offset;
position.VisualColumn = visualLine.ValidateVisualColumn(position, textArea.Selection.EnableVirtualSpace);
// search possible caret positions
int newVisualColumnForwards = visualLine.GetNextCaretPosition(position.VisualColumn - 1, LogicalDirection.Forward, CaretPositioningMode.Normal, textArea.Selection.EnableVirtualSpace);
// If position.VisualColumn was valid, we're done with validation.
if (newVisualColumnForwards != position.VisualColumn) {
// also search backwards so that we can pick the better match
int newVisualColumnBackwards = visualLine.GetNextCaretPosition(position.VisualColumn + 1, LogicalDirection.Backward, CaretPositioningMode.Normal, textArea.Selection.EnableVirtualSpace);
if (newVisualColumnForwards < 0 && newVisualColumnBackwards < 0)
throw ThrowUtil.NoValidCaretPosition();
// determine offsets for new visual column positions
int newOffsetForwards;
if (newVisualColumnForwards >= 0)
newOffsetForwards = visualLine.GetRelativeOffset(newVisualColumnForwards) + firstDocumentLineOffset;
else
newOffsetForwards = -1;
int newOffsetBackwards;
if (newVisualColumnBackwards >= 0)
newOffsetBackwards = visualLine.GetRelativeOffset(newVisualColumnBackwards) + firstDocumentLineOffset;
else
newOffsetBackwards = -1;
int newVisualColumn, newOffset;
// if there's only one valid position, use it
if (newVisualColumnForwards < 0) {
newVisualColumn = newVisualColumnBackwards;
newOffset = newOffsetBackwards;
} else if (newVisualColumnBackwards < 0) {
newVisualColumn = newVisualColumnForwards;
newOffset = newOffsetForwards;
} else {
// two valid positions: find the better match
if (Math.Abs(newOffsetBackwards - caretOffset) < Math.Abs(newOffsetForwards - caretOffset)) {
// backwards is better
newVisualColumn = newVisualColumnBackwards;
newOffset = newOffsetBackwards;
} else {
// forwards is better
newVisualColumn = newVisualColumnForwards;
newOffset = newOffsetForwards;
}
}
this.Position = new TextViewPosition(textView.Document.GetLocation(newOffset), newVisualColumn);
}
}