private static DummyAtom ChangeAtomToOrdinary(DummyAtom currentAtom, DummyAtom previousAtom, Atom nextAtom)
{
var type = currentAtom.GetLeftType();
if (type == TexAtomType.BinaryOperator && (previousAtom == null ||
binaryOperatorChangeSet[(int)previousAtom.GetRightType()]))
{
currentAtom = currentAtom.WithType(TexAtomType.Ordinary);
}
else if (nextAtom != null && currentAtom.GetRightType() == TexAtomType.BinaryOperator)
{
var nextType = nextAtom.GetLeftType();
if (nextType == TexAtomType.Relation || nextType == TexAtomType.Closing || nextType == TexAtomType.Punctuation)
{
currentAtom = currentAtom.WithType(TexAtomType.Ordinary);
}
}
return(currentAtom);
}
protected override Box CreateBoxCore(TexEnvironment environment)
{
// Create result box.
var resultBox = new HorizontalBox(environment.Foreground, environment.Background);
var previousAtom = this.PreviousAtom;
// Create and add box for each atom in row.
for (int i = 0; i < this.Elements.Count; i++)
{
var curAtom = new DummyAtom(this.Elements[i]);
// Change atom type to Ordinary, if required.
var hasNextAtom = i < this.Elements.Count - 1;
var nextAtom = hasNextAtom ? (Atom)this.Elements[i + 1] : null;
curAtom = ChangeAtomToOrdinary(curAtom, previousAtom, nextAtom);
// Check if atom is part of ligature or should be kerned.
var kern = 0d;
if (hasNextAtom && curAtom.GetRightType() == TexAtomType.Ordinary && curAtom.Atom is CharSymbol cs)
{
if (nextAtom is CharSymbol ns && ligatureKernChangeSet[(int)nextAtom.GetLeftType()])
{
var font = ns.GetStyledFont(environment);
var style = environment.Style;
curAtom = curAtom.AsTextSymbol();
if (font.SupportsMetrics && cs.IsSupportedByFont(font, style))
{
var leftAtomCharFont = curAtom.GetCharFont(font).Value;
var rightAtomCharFont = ns.GetCharFont(font).Value;
var ligatureCharFont = font.GetLigature(leftAtomCharFont, rightAtomCharFont);
if (ligatureCharFont == null)
{
// Atom should be kerned.
kern = font.GetKern(leftAtomCharFont, rightAtomCharFont, style);
}
else
{
// Atom is part of ligature.
curAtom = DummyAtom.CreateLigature(new FixedCharAtom(null, ligatureCharFont));
i++;
}
}
}
}
// Create and add glue box, unless atom is first of row or previous/current atom is kern.
if (i != 0 && previousAtom != null && !previousAtom.IsKern && !curAtom.IsKern)
{
resultBox.Add(Glue.CreateBox(previousAtom.GetRightType(), curAtom.GetLeftType(), environment));
}
// Create and add box for atom.
var curBox = curAtom.WithPreviousAtom(previousAtom).CreateBox(environment);
resultBox.Add(curBox);
environment.LastFontId = curBox.GetLastFontId();
// Insert kern, if required.
if (kern > TexUtilities.FloatPrecision)
{
resultBox.Add(new StrutBox(0, kern, 0, 0));
}
if (!curAtom.IsKern)
{
previousAtom = curAtom;
}
}
return(resultBox);
}