// Get the width of the span in pixels.
private int GetSpanWidth(CharSpan span)
{
if (_text == null || _format == null)
{
throw new InvalidOperationException();
}
// set the width of the span, if needed
if (span.pixelWidth != -1)
{
return(span.pixelWidth);
}
// get the text of the span
string s = _text.Substring(span.start, span.length);
// set the width of the span
span.pixelWidth = MeasureStringWidth(s, _measureLayoutRect, _format);
// return the width of the span
return(span.pixelWidth);
}
// Get the next span of characters.
private void GetNextSpan(CharSpan span)
{
if (_text == null)
{
throw new InvalidOperationException();
}
// set new line flag
var newline = false;
// get the start index
var start = nextIndex;
// handle whitespace span
while (nextIndex < _text.Length && _text[nextIndex] == ' ')
{
++nextIndex;
}
// handle word span
if (nextIndex == start)
{
// find the end of the word
while (nextIndex < _text.Length)
{
// get the current character
char c = _text[nextIndex];
// find the end of the word
if (c == ' ' || c == '\n' || c == '\r')
{
break;
}
// we also split on minus to mimic MS behavior
if (c == '-')
{
nextIndex++;
break;
}
// move to the next character
++nextIndex;
}
}
// get the length of the span
int length = nextIndex - start;
// handle new line characters
if (nextIndex < _text.Length)
{
// get the current character
char c = _text[nextIndex];
// check for new line characters
if (c == '\r')
{
// move past the carriage return
++nextIndex;
// move past the line feed, if needed
if (nextIndex < _text.Length &&
_text[nextIndex] == '\n')
{
++nextIndex;
}
// set the new line flag
newline = true;
}
else if (c == '\n')
{
// move past the line feed
++nextIndex;
// set the new line flag
newline = true;
}
}
// set the span values
span.Set(start, length, prevIsNewLine);
// update the previous span ended in new line flag
prevIsNewLine = newline;
// handle wrapping
CheckForWrap(span);
}