public FontGlyph CreateGlyph(char c, int size, float deviceScale)
{
var scaledSize = (uint)(size * deviceScale);
if (FreeType.FT_Set_Pixel_Sizes(face, scaledSize, scaledSize) != FreeType.OK)
{
return(EmptyGlyph);
}
if (FreeType.FT_Load_Char(face, c, FreeType.FT_LOAD_RENDER) != FreeType.OK)
{
return(EmptyGlyph);
}
// Extract the glyph data we care about
// HACK: This uses raw pointer offsets to avoid defining structs and types that are 95% unnecessary
var glyph = Marshal.ReadIntPtr(IntPtr.Add(face, FreeType.FaceRecGlyphOffset)); // face->glyph
var metrics = IntPtr.Add(glyph, FreeType.GlyphSlotMetricsOffset); // face->glyph->metrics
var metricsWidth = Marshal.ReadIntPtr(IntPtr.Add(metrics, FreeType.MetricsWidthOffset)); // face->glyph->metrics.width
var metricsHeight = Marshal.ReadIntPtr(IntPtr.Add(metrics, FreeType.MetricsHeightOffset)); // face->glyph->metrics.width
var metricsAdvance = Marshal.ReadIntPtr(IntPtr.Add(metrics, FreeType.MetricsAdvanceOffset)); // face->glyph->metrics.horiAdvance
var bitmap = IntPtr.Add(glyph, FreeType.GlyphSlotBitmapOffset); // face->glyph->bitmap
var bitmapPitch = Marshal.ReadInt32(IntPtr.Add(bitmap, FreeType.BitmapPitchOffset)); // face->glyph->bitmap.pitch
var bitmapBuffer = Marshal.ReadIntPtr(IntPtr.Add(bitmap, FreeType.BitmapBufferOffset)); // face->glyph->bitmap.buffer
var bitmapLeft = Marshal.ReadInt32(IntPtr.Add(glyph, FreeType.GlyphSlotBitmapLeftOffset)); // face->glyph.bitmap_left
var bitmapTop = Marshal.ReadInt32(IntPtr.Add(glyph, FreeType.GlyphSlotBitmapTopOffset)); // face->glyph.bitmap_top
// Convert FreeType's 26.6 fixed point format to integers by discarding fractional bits
var glyphSize = new Size((int)metricsWidth >> 6, (int)metricsHeight >> 6);
var glyphAdvance = (int)metricsAdvance >> 6;
var g = new FontGlyph
{
Advance = glyphAdvance,
Offset = new int2(bitmapLeft, -bitmapTop),
Size = glyphSize,
Data = new byte[glyphSize.Width * glyphSize.Height]
};
unsafe
{
var p = (byte *)bitmapBuffer;
var k = 0;
for (var j = 0; j < glyphSize.Height; j++)
{
for (var i = 0; i < glyphSize.Width; i++)
{
g.Data[k++] = p[i];
}
p += bitmapPitch;
}
}
return(g);
}
public void Dispose()
{
if (!disposed)
{
if (faceHandle.IsAllocated)
{
FreeType.FT_Done_Face(face);
faceHandle.Free();
disposed = true;
}
}
}
public FreeTypeFont(byte[] data)
{
if (library == IntPtr.Zero && FreeType.FT_Init_FreeType(out library) != FreeType.OK)
{
throw new InvalidOperationException("Failed to initialize FreeType");
}
faceHandle = GCHandle.Alloc(data, GCHandleType.Pinned);
if (FreeType.FT_New_Memory_Face(library, faceHandle.AddrOfPinnedObject(), data.Length, 0, out face) != FreeType.OK)
{
throw new InvalidDataException("Failed to initialize font");
}
}
public void SetSize(int size, float deviceScale)
{
var scaledSize = (uint)(size * deviceScale);
if (FreeType.FT_Set_Pixel_Sizes(face, scaledSize, scaledSize) != FreeType.OK)
{
throw new InvalidDataException("Failed to set size");
}
var faceSize = Marshal.ReadIntPtr(IntPtr.Add(face, FreeType.FaceRecSizeOffset)); // face->size
var metrics = IntPtr.Add(faceSize, FreeType.SizeRecMetricsOffset); // face->size->metrics
var ascender = Marshal.ReadIntPtr(IntPtr.Add(metrics, FreeType.SizeMetricsAscenderOffset)); // face->size->metrics.ascender
var descender = Marshal.ReadIntPtr(IntPtr.Add(metrics, FreeType.SizeMetricsDescenderOffset)); // face->size->metrics.descender
var ascenderValue = (int)ascender >> 6;
var descenderValue = (int)descender >> 6;
Height = (int)((ascenderValue - Math.Abs(descenderValue)) / deviceScale);
}
