public static void RecalculateSpanPositions(this TextView textView, Label element, SpannableString spannableString, SizeRequest finalSize)
{
if (element?.FormattedText?.Spans == null || element.FormattedText.Spans.Count == 0)
{
return;
}
var labelWidth = finalSize.Request.Width;
if (labelWidth <= 0 || finalSize.Request.Height <= 0)
{
return;
}
if (spannableString == null || spannableString.IsDisposed())
{
return;
}
var layout = textView.Layout;
if (layout == null)
{
return;
}
int next = 0;
int count = 0;
IList <int> totalLineHeights = new List <int>();
for (int i = 0; i < spannableString.Length(); i = next)
{
var type = Java.Lang.Class.FromType(typeof(Java.Lang.Object));
var span = element.FormattedText.Spans[count];
count++;
if (string.IsNullOrEmpty(span.Text))
{
continue;
}
// find the next span
next = spannableString.NextSpanTransition(i, spannableString.Length(), type);
// get all spans in the range - Android can have overlapping spans
var spans = spannableString.GetSpans(i, next, type);
var startSpan = spans[0];
var endSpan = spans[spans.Length - 1];
var startSpanOffset = spannableString.GetSpanStart(startSpan);
var endSpanOffset = spannableString.GetSpanEnd(endSpan);
var thisLine = layout.GetLineForOffset(endSpanOffset);
var lineStart = layout.GetLineStart(thisLine);
var lineEnd = layout.GetLineEnd(thisLine);
//If this is true, endSpanOffset has the value for another line that belong to the next span and not it self.
//So it should be rearranged to value not pass the lineEnd.
if (endSpanOffset > (lineEnd - lineStart))
{
endSpanOffset = lineEnd;
}
var startX = layout.GetPrimaryHorizontal(startSpanOffset);
var endX = layout.GetPrimaryHorizontal(endSpanOffset);
var startLine = layout.GetLineForOffset(startSpanOffset);
var endLine = layout.GetLineForOffset(endSpanOffset);
double[] lineHeights = new double[endLine - startLine + 1];
// calculate all the different line heights
for (var lineCount = startLine; lineCount <= endLine; lineCount++)
{
var lineHeight = layout.GetLineBottom(lineCount) - layout.GetLineTop(lineCount);
lineHeights[lineCount - startLine] = lineHeight;
if (totalLineHeights.Count <= lineCount)
{
totalLineHeights.Add(lineHeight);
}
}
var yaxis = 0.0;
for (var line = startLine; line > 0; line--)
{
yaxis += totalLineHeights[line];
}
((ISpatialElement)span).Region = Region.FromLines(lineHeights, labelWidth, startX, endX, yaxis).Inflate(10);
}
}