private void UpdateGlyphInfo(string text, GlyphTypeface glyphTypeface, float fontSize)
{
var glyphs = new ushort[text.Length];
var advances = new float[text.Length];
var scale = fontSize / glyphTypeface.DesignEmHeight;
var width = 0f;
var characters = text.AsSpan();
for (int i = 0; i < characters.Length; i++)
{
var c = characters[i];
float advance;
ushort glyph;
switch (c)
{
case (char)0:
{
glyph = glyphTypeface.GetGlyph(0x200B);
advance = 0;
break;
}
case '\t':
{
glyph = glyphTypeface.GetGlyph(' ');
advance = glyphTypeface.GetGlyphAdvance(glyph) * scale * 4;
break;
}
default:
{
glyph = glyphTypeface.GetGlyph(c);
advance = glyphTypeface.GetGlyphAdvance(glyph) * scale;
break;
}
}
glyphs[i] = glyph;
advances[i] = advance;
width += advance;
}
_glyphs = new ReadOnlySlice <ushort>(glyphs);
_advances = new ReadOnlySlice <float>(advances);
}
double MeasureGlyphAt(int index)
{
return(_typeFace.GetGlyphAdvance(
_typeFace.GetGlyph(_range[index])) * _scale);
}