/// <summary>
/// Select all the words that are between <paramref name="selectionStart"/> word and <paramref name="selectionEnd"/> word in the DOM hierarchy.
/// </summary>
/// <param name="box">the current traversal node</param>
/// <param name="selectionStart">selection start word limit</param>
/// <param name="selectionEnd">selection end word limit</param>
/// <param name="inSelection">used to know the traversal is currently in selected range</param>
/// <returns></returns>
private bool SelectWordsInRange(CssBox box, CssBoxWord selectionStart, CssBoxWord selectionEnd, ref bool inSelection)
{
foreach (var boxWord in box.Words)
{
if (!inSelection && boxWord == selectionStart)
{
inSelection = true;
}
if (inSelection)
{
boxWord.Selection = this;
if (selectionStart == selectionEnd || boxWord == selectionEnd)
{
return(true);
}
}
}
foreach (var childBox in box.Boxes)
{
if (SelectWordsInRange(childBox, selectionStart, selectionEnd, ref inSelection))
{
return(true);
}
}
return(false);
}
/// <summary>
/// Find the css line box that the given word is in.
/// </summary>
/// <param name="word">the word to search for it's line box</param>
/// <returns>line box that the word is in</returns>
public static CssLineBox GetCssLineBoxByWord(CssBoxWord word)
{
var box = word.OwnerBox;
while (box != null && box.LineBoxes.Count == 0)
{
box = box.ParentBox;
}
if (box == null)
{
return(null);
}
foreach (var lineBox in box.LineBoxes)
{
foreach (var lineWord in lineBox.Words)
{
if (lineWord == word)
{
return(lineBox);
}
}
}
return(box.LineBoxes[0]);
}
/// <summary>
/// Select the word at the given location if found.
/// </summary>
/// <param name="control">the control hosting the html to invalidate</param>
/// <param name="loc">the location to select word at</param>
public void SelectWord(Control control, Point loc)
{
var word = DomUtils.GetCssBoxWord(_root, loc);
if (word != null)
{
word.Selection = this;
_selectionStartPoint = loc;
_selectionStart = _selectionEnd = word;
control.Invalidate();
}
}
/// <summary>
/// Calculate the charecter index and offset by charecters for the given word and given offset.
/// If the location is below the word line then set the selection to the end.<br/>
/// If the location is to the right of the word then set the selection to the end.<br/>
/// If the offset is to the left of the word set the selection to the begining.<br/>
/// Otherwise calculate the width of each substring to find the char the location is on.
/// </summary>
/// <param name="control">used to create graphics to measure string</param>
/// <param name="word">the word to calculate its index and offset</param>
/// <param name="loc">the location to calculate for</param>
/// <param name="selectionIndex">return the index of the char under the location</param>
/// <param name="selectionOffset">return the offset of the char under the location</param>
/// <param name="inclusive">is to include the first charecter in the calculation</param>
private static void CalculateWordCharIndexAndOffset(Control control, CssBoxWord word, Point loc, bool inclusive, out int selectionIndex, out float selectionOffset)
{
selectionIndex = 0;
selectionOffset = 0.1f;
var offset = loc.X - word.Left;
if (word.Text == null)
{
// not a text word - set full selection
selectionIndex = -1;
selectionOffset = -1;
}
else if (offset > word.Width - word.OwnerBox.ActualWordSpacing || loc.Y > word.LineBox.LineBottom)
{
// mouse under the line, to the right of the word - set to the end of the word
selectionIndex = word.Text.Length;
selectionOffset = word.Width;
}
else if (offset > 0)
{
// calculate partial word selection
selectionIndex = word.Text.Length;
selectionOffset = word.OwnerBox.ActualWordSpacing / 2f;
using (var g = control.CreateGraphics())
{
for (int i = 1; i <= word.Text.Length; i++)
{
var sf = new StringFormat();
sf.SetMeasurableCharacterRanges(new[] { new CharacterRange(0, i) });
var regions = g.MeasureCharacterRanges(word.Text, word.OwnerBox.ActualFont, new RectangleF(0, 0, float.MaxValue, float.MaxValue), sf);
SizeF s = regions[0].GetBounds(g).Size;
if (!inclusive)
{
selectionOffset = s.Width + (s.Width / i / 15f);
}
if (s.Width > offset)
{
selectionIndex = i - (inclusive ? 1 : 0);
break;
}
selectionOffset = s.Width + (s.Width / i / 15f);
}
}
}
}
/// <summary>
/// Clear the current selection.
/// </summary>
private void ClearSelection()
{
// clear drag and drop
_dragDropData = null;
ClearSelection(_root);
_selectionStartOffset = -1;
_selectionStartIndex = -1;
_selectionEndOffset = -1;
_selectionEndIndex = -1;
_selectionStartPoint = Point.Empty;
_selectionStart = null;
_selectionEnd = null;
}
/// <summary>
/// Calculate the charecter index and offset by charecters for the given word and given offset.<br/>
/// <seealso cref="CalculateWordCharIndexAndOffset(Control, CssBoxWord, Point, bool, out int, out float)"/>.
/// </summary>
/// <param name="control">used to create graphics to measure string</param>
/// <param name="word">the word to calculate its index and offset</param>
/// <param name="loc">the location to calculate for</param>
/// <param name="selectionStart">to set the starting or ending char and offset data</param>
private void CalculateWordCharIndexAndOffset(Control control, CssBoxWord word, Point loc, bool selectionStart)
{
int selectionIndex;
float selectionOffset;
CalculateWordCharIndexAndOffset(control, word, loc, selectionStart, out selectionIndex, out selectionOffset);
if (selectionStart)
{
_selectionStartIndex = selectionIndex;
_selectionStartOffset = selectionOffset;
}
else
{
_selectionEndIndex = selectionIndex;
_selectionEndOffset = selectionOffset;
}
}
/// <summary>
/// Get the selected word with respect to partial selected words.
/// </summary>
/// <param name="boxWord">the word to append</param>
/// <param name="selectedText">is to get selected text or all the text in the word</param>
private static string GetSelectedWord(CssBoxWord boxWord, bool selectedText)
{
if (selectedText && boxWord.SelectedStartIndex > -1 && boxWord.SelectedEndIndexOffset > -1)
{
return(boxWord.Text.Substring(boxWord.SelectedStartIndex, boxWord.SelectedEndIndexOffset - boxWord.SelectedStartIndex));
}
else if (selectedText && boxWord.SelectedStartIndex > -1)
{
return(boxWord.Text.Substring(boxWord.SelectedStartIndex) + " ");
}
else if (selectedText && boxWord.SelectedEndIndexOffset > -1)
{
return(boxWord.Text.Substring(0, boxWord.SelectedEndIndexOffset));
}
else
{
return(boxWord.Text + " ");
}
}
/// <summary>
/// Select all the words that are between <paramref name="selectionStart"/> word and <paramref name="selectionEnd"/> word in the DOM hierarchy.<br/>
/// </summary>
/// <param name="root">the root of the DOM sub-tree the selection is in</param>
/// <param name="selectionStart">selection start word limit</param>
/// <param name="selectionEnd">selection end word limit</param>
private void SelectWordsInRange(CssBox root, CssBoxWord selectionStart, CssBoxWord selectionEnd)
{
bool inSelection = false;
SelectWordsInRange(root, selectionStart, selectionEnd, ref inSelection);
}
/// <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(Control control, Point 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 uner 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;
}
control.Cursor = Cursors.IBeam;
control.Invalidate();
}
}
}
/// <summary>
/// The selection end offset if the last selected word is partially selected (-1 if not selected or fully selected)<br/>
/// if the given word is not starting or ending selection word -1 is returned as full word selection is in place.
/// </summary>
/// <remarks>
/// Handles backward selecting by returning the selection end data instead of start.
/// </remarks>
/// <param name="word">the word to return the selection end offset for</param>
public float GetSelectedEndOffset(CssBoxWord word)
{
return(word == (_backwardSelection ? _selectionStart : _selectionEnd) ? (_backwardSelection ? _selectionStartOffset : _selectionEndOffset) : -1);
}
/// <summary>
/// The selection end index if the last selected word is partially selected (-1 if not selected or fully selected)<br/>
/// if the given word is not starting or ending selection word -1 is returned as full word selection is in place.
/// </summary>
/// <remarks>
/// Handles backward selecting by returning the selection end data instead of start.
/// </remarks>
/// <param name="word">the word to return the selection end index for</param>
public int GetSelectedEndIndexOffset(CssBoxWord word)
{
return(word == (_backwardSelection ? _selectionStart : _selectionEnd) ? (_backwardSelection ? _selectionStartIndex : _selectionEndIndex) : -1);
}
/// <summary>
/// The selection start index if the first selected word is partially selected (-1 if not selected or fully selected)<br/>
/// if the given word is not starting or ending selection word -1 is returned as full word selection is in place.
/// </summary>
/// <remarks>
/// Handles backward selecting by returning the selection end data instead of start.
/// </remarks>
/// <param name="word">the word to return the selection start index for</param>
/// <returns>data value or -1 if not aplicable</returns>
public int GetSelectingStartIndex(CssBoxWord word)
{
return(word == (_backwardSelection ? _selectionEnd : _selectionStart) ? (_backwardSelection ? _selectionEndIndex : _selectionStartIndex) : -1);
}