public FontGlyph ParseCffGlyph(int index, float scale)
{
var glyphData = new CffGlyphFactory(scale);
bool successful = RunCharstring(index, glyphData);
if (!successful)
{
Engine.Log.Warning($"Couldn't read CFF glyff - {index}", MessageSource.FontParser);
}
return(glyphData.Glyph);
}
/// <summary>
/// Horrible
/// https://www.adobe.com/devnet/font.html
/// </summary>
private bool RunCharstring(int glyphIndex, CffGlyphFactory c)
{
var inHeader = true;
var maskBits = 0;
var subrStackHeight = 0;
var sp = 0;
var hasSubrs = false;
// Argument stack.
var s = new float[48];
// Subr nesting stack.
var subrStack = new ByteReader[10];
using var defaultB = new ByteReader(CharStringIndex[glyphIndex]);
ByteReader b = defaultB;
while (b.Position < b.Data.Length)
{
var i = 0;
var clearStack = true;
int b0 = b.ReadByte();
float f;
switch (b0)
{
case 0x13:
case 0x14:
if (inHeader)
{
maskBits += sp / 2;
}
inHeader = false;
b.ReadBytes((maskBits + 7) / 8);
break;
case 0x01:
case 0x03:
case 0x12:
case 0x17:
maskBits += sp / 2;
break;
case 0x15:
inHeader = false;
if (sp < 2)
{
return(false);
}
c.MoveTo(s[sp - 2], s[sp - 1]);
break;
case 0x04:
inHeader = false;
if (sp < 1)
{
return(false);
}
c.MoveTo(0, s[sp - 1]);
break;
case 0x16:
inHeader = false;
if (sp < 1)
{
return(false);
}
c.MoveTo(s[sp - 1], 0);
break;
case 0x05:
if (sp < 2)
{
return(false);
}
for (; i + 1 < sp; i += 2)
{
c.LineTo(s[i], s[i + 1]);
}
break;
case 0x07:
case 0x06:
if (sp < 1)
{
return(false);
}
bool gotoVLineTo = b0 == 0x07;
for (;;)
{
if (!gotoVLineTo)
{
if (i >= sp)
{
break;
}
c.LineTo(s[i], 0);
i++;
}
gotoVLineTo = false;
if (i >= sp)
{
break;
}
c.LineTo(0, s[i]);
i++;
}
break;
case 0x1F:
case 0x1E:
if (sp < 4)
{
return(false);
}
bool gotoHvCurveTo = b0 == 0x1F;
for (;;)
{
if (!gotoHvCurveTo)
{
if (i + 3 >= sp)
{
break;
}
c.CubicCurveTo(0, s[i], s[i + 1],
s[i + 2], s[i + 3],
sp - i == 5 ? s[i + 4] : 0.0f);
i += 4;
}
gotoHvCurveTo = false;
if (i + 3 >= sp)
{
break;
}
c.CubicCurveTo(s[i], 0, s[i + 1],
s[i + 2], sp - i == 5 ? s[i + 4] : 0.0f, s[i + 3]);
i += 4;
}
break;
case 0x08:
if (sp < 6)
{
return(false);
}
for (; i + 5 < sp; i += 6)
{
c.CubicCurveTo(s[i], s[i + 1], s[i + 2],
s[i + 3], s[i + 4], s[i + 5]);
}
break;
case 0x18:
if (sp < 8)
{
return(false);
}
for (; i + 5 < sp - 2; i += 6)
{
c.CubicCurveTo(s[i], s[i + 1], s[i + 2],
s[i + 3], s[i + 4], s[i + 5]);
}
if (i + 1 >= sp)
{
return(false);
}
c.LineTo(s[i], s[i + 1]);
break;
case 0x19:
if (sp < 8)
{
return(false);
}
for (; i + 1 < sp - 6; i += 2)
{
c.LineTo(s[i], s[i + 1]);
}
if (i + 5 >= sp)
{
return(false);
}
c.CubicCurveTo(s[i], s[i + 1], s[i + 2],
s[i + 3], s[i + 4], s[i + 5]);
break;
case 0x1A:
case 0x1B:
if (sp < 4)
{
return(false);
}
f = 0.0f;
if ((sp & 1) != 0)
{
f = s[i];
i++;
}
for (; i + 3 < sp; i += 4)
{
if (b0 == 0x1B)
{
c.CubicCurveTo(s[i], f, s[i + 1],
s[i + 2], s[i + 3], (float)0.0);
}
else
{
c.CubicCurveTo(f, s[i], s[i + 1],
s[i + 2], (float)0.0, s[i + 3]);
}
f = 0.0f;
}
break;
case 0x0A:
case 0x1D:
if (b0 == 0x0A)
{
if (!hasSubrs)
{
// todo
//if (FdSelect.Length != 0)
// subrs = new ByteReader(Subr[glyphIndex]);
hasSubrs = true;
}
}
if (sp < 1)
{
return(false);
}
var v = (int)s[--sp];
if (subrStackHeight >= 10)
{
return(false);
}
subrStack[subrStackHeight++] = b;
b = b0 == 0x0A ? new ByteReader(Subr[v + SubrBias]) : new ByteReader(GlobalSubrIndex[v + GlobalBias]);
if (b.Data.Length == 0)
{
return(false);
}
b.Position = 0;
clearStack = false;
break;
case 0x0B:
if (subrStackHeight <= 0)
{
return(false);
}
b = subrStack[--subrStackHeight];
clearStack = false;
break;
case 0x0E:
c.CloseShape();
c.Done();
return(true);
case 0x0C:
{
float dx1;
float dx2;
float dx3;
float dx4;
float dx5;
float dx6;
float dy1;
float dy2;
float dy3;
float dy4;
float dy5;
float dy6;
int b1 = b.ReadByte();
switch (b1)
{
case 0x22:
if (sp < 7)
{
return(false);
}
dx1 = s[0];
dx2 = s[1];
dy2 = s[2];
dx3 = s[3];
dx4 = s[4];
dx5 = s[5];
dx6 = s[6];
c.CubicCurveTo(dx1, 0, dx2, dy2,
dx3, 0);
c.CubicCurveTo(dx4, 0, dx5, -dy2,
dx6, 0);
break;
case 0x23:
if (sp < 13)
{
return(false);
}
dx1 = s[0];
dy1 = s[1];
dx2 = s[2];
dy2 = s[3];
dx3 = s[4];
dy3 = s[5];
dx4 = s[6];
dy4 = s[7];
dx5 = s[8];
dy5 = s[9];
dx6 = s[10];
dy6 = s[11];
c.CubicCurveTo(dx1, dy1, dx2, dy2,
dx3, dy3);
c.CubicCurveTo(dx4, dy4, dx5, dy5,
dx6, dy6);
break;
case 0x24:
if (sp < 9)
{
return(false);
}
dx1 = s[0];
dy1 = s[1];
dx2 = s[2];
dy2 = s[3];
dx3 = s[4];
dx4 = s[5];
dx5 = s[6];
dy5 = s[7];
dx6 = s[8];
c.CubicCurveTo(dx1, dy1, dx2, dy2,
dx3, 0);
c.CubicCurveTo(dx4, 0, dx5, dy5,
dx6, -(dy1 + dy2 + dy5));
break;
case 0x25:
if (sp < 11)
{
return(false);
}
dx1 = s[0];
dy1 = s[1];
dx2 = s[2];
dy2 = s[3];
dx3 = s[4];
dy3 = s[5];
dx4 = s[6];
dy4 = s[7];
dx5 = s[8];
dy5 = s[9];
dx6 = dy6 = s[10];
float dx = dx1 + dx2 + dx3 + dx4 + dx5;
float dy = dy1 + dy2 + dy3 + dy4 + dy5;
if (MathF.Abs(dx) > MathF.Abs(dy))
{
dy6 = -dy;
}
else
{
dx6 = -dx;
}
c.CubicCurveTo(dx1, dy1, dx2, dy2,
dx3, dy3);
c.CubicCurveTo(dx4, dy4, dx5, dy5,
dx6, dy6);
break;
default:
return(false);
}
}
break;
default:
if (b0 != 255 && b0 != 28 && (b0 < 32 || b0 > 254))
{
return(false);
}
if (b0 == 255)
{
f = (float)b.ReadUIntBE() / 0x10000;
}
else
{
b.Position -= 1;
f = (short)ReadCffInt(b);
}
if (sp >= 48)
{
return(false);
}
s[sp++] = f;
clearStack = false;
break;
}
if (clearStack)
{
sp = 0;
}
}
return(false);
}
