/// <summary>
/// Calculate the character index and offset by characters for the given word and given offset.<br/>
/// 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 beginning.<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 character in the calculation</param>
private static void CalculateWordCharIndexAndOffset(Control control, CssRect word, Point loc, bool inclusive, out int selectionIndex, out float selectionOffset)
{
selectionIndex = 0;
selectionOffset = 0f;
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 > DomUtils.GetCssLineBoxByWord(word).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
var font = word.OwnerBox.ActualFont;
using (var g = new WinGraphics(control.CreateGraphics(), false))
{
int charFit;
int charFitWidth;
var maxWidth = offset + (inclusive ? 0 : 1.5f * word.LeftGlyphPadding);
g.MeasureString(word.Text, font, maxWidth, out charFit, out charFitWidth);
selectionIndex = charFit;
selectionOffset = charFitWidth;
}
}
}
/// <summary>
/// Calculate the character index and offset by characters for the given word and given offset.<br/>
/// 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 beginning.<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 character in the calculation</param>
private static void CalculateWordCharIndexAndOffset(Control control, CssRect word, Point loc, bool inclusive, out int selectionIndex, out float selectionOffset)
{
selectionIndex = 0;
selectionOffset = 0f;
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 > DomUtils.GetCssLineBoxByWord(word).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
var font = word.OwnerBox.ActualFont;
using (var g = new WinGraphics(control.CreateGraphics()))
{
int charFit;
int charFitWidth;
var maxWidth = offset + ( inclusive ? 0 : 1.5f*word.LeftGlyphPadding );
g.MeasureString(word.Text, font, maxWidth, out charFit, out charFitWidth);
selectionIndex = charFit;
selectionOffset = charFitWidth;
}
}
}