private static FontData GetFontData(Typeface typeface, double fontSize)
{
if (!typeface.Equals(cachedTypeface) || fontSize != cachedFontSize)
{
if (!typeface.TryGetGlyphTypeface(out GlyphTypeface glyphTypeface))
{
defaultTypface.TryGetGlyphTypeface(out glyphTypeface);
}
bool charactersFound = GetTextBounds(glyphTypeface, fontSize, out double topDistance, out double bottomDistance);
fontCache = new FontData(glyphTypeface, topDistance, bottomDistance, charactersFound);
cachedTypeface = typeface;
cachedFontSize = fontSize;
}
return(fontCache);
}
public static double FontHeight(Typeface typeface, double fontSize, double dpiScale)
{
FontData fontData = GetFontData(typeface, fontSize);
if (!fontData.HeightsCalculated)
{
return(MeasureText("A", typeface, fontSize, dpiScale).Height);
}
double topDistance = fontData.TopDistance;
if (fontData.GlyphTypeface.Baseline * fontSize > fontData.TopDistance)
{
topDistance = fontData.GlyphTypeface.Baseline * fontSize * fontData.GlyphTypeface.Height;
}
return((Math.Ceiling(topDistance / dpiScale) * dpiScale) + (Math.Ceiling(fontData.BottomDistance / dpiScale) * dpiScale));
}
internal static GlyphRun CreateGlyphRun(string text, Typeface typeface, double fontSize, double dpiScale, double glyphRunStartPosition, out double runWidth)
{
if (text.Length == 0)
{
runWidth = 0;
return(null);
}
FontData fontData = GetFontData(typeface, fontSize);
ushort[] glyphIndexes = new ushort[text.Length];
double[] advanceWidths = new double[text.Length];
double totalWidth = 0;
int codePoint;
for (int n = 0; n < text.Length; n++)
{
// C# uses UTF16 encoded strings which for some characters requires 2 surrogate pair chars to encode
// one character, if so we add a zero width space glyph after the real glyph to keep the number of
// glyphs in the glyph run the same as the number of chars in the string to easier map mouse clicks
// to whole characters in case a surrogate pair is used.
if (char.IsHighSurrogate(text[n]))
{
codePoint = char.ConvertToUtf32(text, n);
}
else if (char.IsLowSurrogate(text[n]))
{
codePoint = '\u200B';
}
else
{
codePoint = text[n];
}
ushort glyphIndex = ReplaceGlyph(codePoint, fontData.GlyphTypeface, fontSize, dpiScale, glyphRunStartPosition + totalWidth, out double width);
glyphIndexes[n] = glyphIndex;
advanceWidths[n] = width;
totalWidth += width;
}
double maxTopDistance = fontData.TopDistance;
if (fontData.GlyphTypeface.Baseline * fontSize > maxTopDistance || !fontData.HeightsCalculated)
{
maxTopDistance = fontData.GlyphTypeface.Baseline * fontSize * fontData.GlyphTypeface.Height;
}
maxTopDistance = Math.Ceiling(maxTopDistance / dpiScale) * dpiScale;
GlyphRun run = new GlyphRun(
glyphTypeface: fontData.GlyphTypeface,
bidiLevel: 0,
isSideways: false,
renderingEmSize: Math.Ceiling(fontSize / dpiScale) * dpiScale,
pixelsPerDip: (float)dpiScale,
glyphIndices: glyphIndexes,
baselineOrigin: new Point(0, maxTopDistance),
advanceWidths: advanceWidths,
glyphOffsets: null,
characters: null,
deviceFontName: null,
clusterMap: null,
caretStops: null,
language: null);
runWidth = totalWidth;
return(run);
}