private static void TrimText(TextBlock textBlock,
string text,
double size,
ICollection <string> segments,
double epsilon,
bool reversed)
{
while (true)
{
if (text.Length == 1)
{
var textSize = TextBlockTrimmer.MeasureString(textBlock, text);
if (textSize <= size)
{
segments.Add(text);
}
return;
}
var halfLength = Math.Max(1, text.Length / 2);
var firstHalf = reversed ? text.Substring(halfLength) : text.Substring(0, halfLength);
var remainingSize = size - TextBlockTrimmer.MeasureString(textBlock, firstHalf);
if (remainingSize < 0)
{
// only one character and it's still too large for the room, skip it
if (firstHalf.Length == 1)
{
return;
}
text = firstHalf;
continue;
}
segments.Add(firstHalf);
if (remainingSize > epsilon)
{
var secondHalf = reversed ? text.Substring(0, halfLength) : text.Substring(halfLength);
text = secondHalf;
size = remainingSize;
continue;
}
break;
}
}
private void TrimText()
{
var textBlock = (TextBlock)this.Content;
if (textBlock == null)
{
return;
}
if (DesignerProperties.GetIsInDesignMode(textBlock))
{
return;
}
var freeSize = _constraint.Width
- this.Padding.Left
- this.Padding.Right
- textBlock.Margin.Left
- textBlock.Margin.Right;
// ReSharper disable once CompareOfFloatsByEqualityOperator
if (freeSize <= 0)
{
return;
}
using (this.BlockTextChangedEvent())
{
// this actually sets textBlock's text back to its original value
var desiredSize = TextBlockTrimmer.MeasureString(textBlock, _originalText);
if (desiredSize <= freeSize)
{
return;
}
var ellipsisSize = TextBlockTrimmer.MeasureString(textBlock, ELLIPSIS);
freeSize -= ellipsisSize;
var epsilon = ellipsisSize / 3;
if (freeSize < epsilon)
{
textBlock.Text = _originalText;
return;
}
var segments = new List <string>();
var builder = new StringBuilder();
switch (this.EllipsisPosition)
{
case EllipsisPosition.End:
TextBlockTrimmer.TrimText(textBlock, _originalText, freeSize, segments, epsilon, false);
foreach (var segment in segments)
{
builder.Append(segment);
}
builder.Append(ELLIPSIS);
break;
case EllipsisPosition.Start:
TextBlockTrimmer.TrimText(textBlock, _originalText, freeSize, segments, epsilon, true);
builder.Append(ELLIPSIS);
foreach (var segment in ((IEnumerable <string>)segments).Reverse())
{
builder.Append(segment);
}
break;
case EllipsisPosition.Middle:
var textLength = _originalText.Length / 2;
var firstHalf = _originalText.Substring(0, textLength);
var secondHalf = _originalText.Substring(textLength);
freeSize /= 2;
TextBlockTrimmer.TrimText(textBlock, firstHalf, freeSize, segments, epsilon, false);
foreach (var segment in segments)
{
builder.Append(segment);
}
builder.Append(ELLIPSIS);
segments.Clear();
TextBlockTrimmer.TrimText(textBlock, secondHalf, freeSize, segments, epsilon, true);
foreach (var segment in ((IEnumerable <string>)segments).Reverse())
{
builder.Append(segment);
}
break;
default:
throw new NotSupportedException();
}
textBlock.Text = builder.ToString();
}
}