/// <summary>
/// Handle html text selection by mouse move over the html with left mouse button pressed.<br/>
/// Calculate the words in the selected range and set their selected property.
/// </summary>
/// <param name="control">the control hosting the html to invalidate</param>
/// <param name="loc">the mouse location</param>
/// <param name="allowPartialSelect">true - partial word selection allowed, false - only full words selection</param>
private void HandleSelection(RControl control, RPoint loc, bool allowPartialSelect)
{
// get the line under the mouse or nearest from the top
var lineBox = DomUtils.GetCssLineBox(_root, loc);
if (lineBox != null)
{
// get the word under the mouse
var word = DomUtils.GetCssBoxWord(lineBox, loc);
// if no word found under the mouse use the last or the first word in the line
if (word == null && lineBox.Words.Count > 0)
{
if (loc.Y > lineBox.LineBottom)
{
// under the line
word = lineBox.Words[lineBox.Words.Count - 1];
}
else if (loc.X < lineBox.Words[0].Left)
{
// before the line
word = lineBox.Words[0];
}
else if (loc.X > lineBox.Words[lineBox.Words.Count - 1].Right)
{
// at the end of the line
word = lineBox.Words[lineBox.Words.Count - 1];
}
}
// if there is matching word
if (word != null)
{
if (_selectionStart == null)
{
// on start set the selection start word
_selectionStartPoint = loc;
_selectionStart = word;
if (allowPartialSelect)
{
CalculateWordCharIndexAndOffset(control, word, loc, true);
}
}
// always set selection end word
_selectionEnd = word;
if (allowPartialSelect)
{
CalculateWordCharIndexAndOffset(control, word, loc, false);
}
ClearSelection(_root);
if (CheckNonEmptySelection(loc, allowPartialSelect))
{
CheckSelectionDirection();
SelectWordsInRange(_root, _backwardSelection ? _selectionEnd : _selectionStart, _backwardSelection ? _selectionStart : _selectionEnd);
}
else
{
_selectionEnd = null;
}
_cursorChanged = true;
control.SetCursorIBeam();
control.Invalidate();
}
}
}