protected override void OnWidthExceeded()
{
if (addingEllipsis)
{
return;
}
addingEllipsis = true;
try
{
if (string.IsNullOrEmpty(ellipsisString))
{
return;
}
// Characters is re-used to reduce allocations, but must be reset after use
int startIndex = Characters.Count;
// Compute the ellipsis to find out the size required
var builder = new TextBuilder(store, font, float.MaxValue, useFontSizeAsHeight, Vector2.Zero, spacing, Characters, neverFixedWidthCharacters, fallbackCharacter);
builder.AddText(ellipsisString);
float ellipsisWidth = builder.Bounds.X;
TextBuilderGlyph firstEllipsisGlyph = builder.Characters[startIndex];
// Reset the characters list by removing all ellipsis characters
Characters.RemoveRange(startIndex, Characters.Count - startIndex);
while (true)
{
RemoveLastCharacter();
if (Characters.Count == 0)
{
break;
}
if (Characters[Characters.Count - 1].IsWhiteSpace())
{
continue;
}
if (base.HasAvailableSpace(firstEllipsisGlyph.GetKerning(Characters[Characters.Count - 1]) + spacing.X + ellipsisWidth))
{
break;
}
}
AddText(ellipsisString);
}
finally
{
addingEllipsis = false;
ellipsisAdded = true;
}
}
/// <summary>
/// Removes the last character added to this <see cref="TextBuilder"/>.
/// If the character is the first character on a new line, the new line is also removed.
/// </summary>
public void RemoveLastCharacter()
{
if (Characters.Count == 0)
{
return;
}
TextBuilderGlyph removedCharacter = Characters[Characters.Count - 1];
TextBuilderGlyph?previousCharacter = Characters.Count == 1 ? null : (TextBuilderGlyph?)Characters[Characters.Count - 2];
Characters.RemoveAt(Characters.Count - 1);
// For each character that is removed:
// 1. Calculate the line height of the last line.
// 2. If the character is the first on a new line, move the current position upwards by the calculated line height and to the end of the previous line.
// The position at the end of the line is the post-XAdvanced position.
// 3. If the character is not the first on a new line, move the current position backwards by the XAdvance and the kerning from the previous glyph.
// This brings the current position to the post-XAdvanced position of the previous glyph.
currentLineHeight = 0;
// This is O(n^2) for removing all characters within a line, but is generally not used in such a case
for (int i = Characters.Count - 1; i >= 0; i--)
{
var character = Characters[i];
currentLineHeight = Math.Max(currentLineHeight, getGlyphHeight(ref character));
if (character.OnNewLine)
{
break;
}
}
if (removedCharacter.OnNewLine)
{
// Move up to the previous line
currentPos.Y -= currentLineHeight;
// If this is the first line (ie. there are no characters remaining) we shouldn't be removing the spacing,
// as there is no spacing applied to the first line.
if (Characters.Count > 0)
{
currentPos.Y -= spacing.Y;
}
currentPos.X = 0;
if (previousCharacter != null)
{
// The character's draw rectangle is the only marker that keeps a constant state for the position, but it has the glyph's XOffset added into it
// So the post-kerned position can be retrieved by taking the XOffset away, and the post-XAdvanced position is retrieved by adding the XAdvance back in
currentPos.X = previousCharacter.Value.DrawRectangle.Left - previousCharacter.Value.XOffset + previousCharacter.Value.XAdvance;
}
}
else
{
// Move back within the current line, reversing the operations in AddCharacter()
currentPos.X -= removedCharacter.XAdvance;
if (previousCharacter != null)
{
currentPos.X -= removedCharacter.GetKerning(previousCharacter.Value) + spacing.X;
}
}
Bounds = Vector2.Zero;
for (int i = 0; i < Characters.Count; i++)
{
// As above, the bounds are calculated through the character draw rectangles
Bounds = Vector2.ComponentMax(
Bounds,
new Vector2(
Characters[i].DrawRectangle.Left - Characters[i].XOffset + Characters[i].XAdvance,
Characters[i].DrawRectangle.Top - Characters[i].YOffset + currentLineHeight)
);
}
// The new line is removed when the first character on the line is removed, thus the current position is never on a new line
// after a character is removed except when there are no characters remaining in the builder
if (Characters.Count == 0)
{
currentNewLine = true;
}
}