static Glyph ReadCompositeGlyph(Glyph[] createdGlyhps, BinaryReader reader, int contourCount, Bounds bounds)
{
//------------------------------------------------------
//https://www.microsoft.com/typography/OTSPEC/glyf.htm
//Composite Glyph Description
//This is the table information needed for composite glyphs (numberOfContours is -1).
//A composite glyph starts with two USHORT values (“flags” and “glyphIndex,” i.e. the index of the first contour in this composite glyph);
//the data then varies according to “flags”).
//Type Name Description
//USHORT flags component flag
//USHORT glyphIndex glyph index of component
//VARIABLE argument1 x-offset for component or point number; type depends on bits 0 and 1 in component flags
//VARIABLE argument2 y-offset for component or point number; type depends on bits 0 and 1 in component flags
//---------
//see more at https://fontforge.github.io/assets/old/Composites/index.html
//---------
Glyph finalGlyph = null;
CompositeGlyphFlags flags;
do
{
flags = (CompositeGlyphFlags)reader.ReadUInt16();
ushort glyphIndex = reader.ReadUInt16();
Glyph newGlyph = Glyph.Clone(createdGlyhps[glyphIndex]);
short arg1 = 0;
short arg2 = 0;
ushort arg1and2 = 0;
if (HasFlag(flags, CompositeGlyphFlags.ARG_1_AND_2_ARE_WORDS))
{
arg1 = reader.ReadInt16();
arg2 = reader.ReadInt16();
}
else
{
byte a1 = reader.ReadByte();
byte a2 = reader.ReadByte();
arg1and2 = (ushort)((a1 << 8) | a2);
}
//-----------------------------------------
float xscale = 1;
float scale01 = 0;
float scale10 = 0;
float yscale = 1;
bool useMatrix = false;
//-----------------------------------------
bool hasScale = false;
if (HasFlag(flags, CompositeGlyphFlags.WE_HAVE_A_SCALE))
{
//If the bit WE_HAVE_A_SCALE is set,
//the scale value is read in 2.14 format-the value can be between -2 to almost +2.
//The glyph will be scaled by this value before grid-fitting.
xscale = yscale = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
hasScale = true;
}
else if (HasFlag(flags, CompositeGlyphFlags.WE_HAVE_AN_X_AND_Y_SCALE))
{
xscale = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
yscale = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
hasScale = true;
}
else if (HasFlag(flags, CompositeGlyphFlags.WE_HAVE_A_TWO_BY_TWO))
{
//The bit WE_HAVE_A_TWO_BY_TWO allows for linear transformation of the X and Y coordinates by specifying a 2 × 2 matrix.
//This could be used for scaling and 90-degree*** rotations of the glyph components, for example.
//2x2 matrix
//The purpose of USE_MY_METRICS is to force the lsb and rsb to take on a desired value.
//For example, an i-circumflex (U+00EF) is often composed of the circumflex and a dotless-i.
//In order to force the composite to have the same metrics as the dotless-i,
//set USE_MY_METRICS for the dotless-i component of the composite.
//Without this bit, the rsb and lsb would be calculated from the hmtx entry for the composite
//(or would need to be explicitly set with TrueType instructions).
//Note that the behavior of the USE_MY_METRICS operation is undefined for rotated composite components.
useMatrix = true;
hasScale = true;
xscale = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
scale01 = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
scale10 = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
yscale = ((float)reader.ReadInt16()) / (1 << 14); /* Format 2.14 */
if (HasFlag(flags, CompositeGlyphFlags.UNSCALED_COMPONENT_OFFSET))
{
}
else
{
}
if (HasFlag(flags, CompositeGlyphFlags.USE_MY_METRICS))
{
}
}
//--------------------------------------------------------------------
if (HasFlag(flags, CompositeGlyphFlags.ARGS_ARE_XY_VALUES))
{
//Argument1 and argument2 can be either x and y offsets to be added to the glyph or two point numbers.
//x and y offsets to be added to the glyph
//When arguments 1 and 2 are an x and a y offset instead of points and the bit ROUND_XY_TO_GRID is set to 1,
//the values are rounded to those of the closest grid lines before they are added to the glyph.
//X and Y offsets are described in FUnits.
if (useMatrix)
{
//use this matrix
Glyph.TransformNormalWith2x2Matrix(newGlyph, xscale, scale01, scale10, yscale);
Glyph.OffsetXY(newGlyph, (short)(arg1), arg2);
}
else
{
if (hasScale)
{
if (xscale == 1.0 && yscale == 1.0)
{
}
else
{
Glyph.TransformNormalWith2x2Matrix(newGlyph, xscale, 0, 0, yscale);
}
Glyph.OffsetXY(newGlyph, arg1, arg2);
}
else
{
if (HasFlag(flags, CompositeGlyphFlags.ROUND_XY_TO_GRID))
{
//TODO: implement round xy to grid***
//----------------------------
}
//just offset***
Glyph.OffsetXY(newGlyph, arg1, arg2);
}
}
}
else
{
//two point numbers.
//the first point number indicates the point that is to be matched to the new glyph.
//The second number indicates the new glyph's “matched” point.
//Once a glyph is added,its point numbers begin directly after the last glyphs (endpoint of first glyph + 1)
}
//
if (finalGlyph == null)
{
finalGlyph = newGlyph;
}
else
{
//merge
Glyph.AppendGlyph(finalGlyph, newGlyph);
}
} while (HasFlag(flags, CompositeGlyphFlags.MORE_COMPONENTS));
if (HasFlag(flags, CompositeGlyphFlags.WE_HAVE_INSTRUCTIONS))
{
ushort numInstr = reader.ReadUInt16();
byte[] insts = reader.ReadBytes(numInstr);
finalGlyph.GlyphInstructions = insts;
}
//F2DOT14 16-bit signed fixed number with the low 14 bits of fraction (2.14).
//Transformation Option
//
//The C pseudo-code fragment below shows how the composite glyph information is stored and parsed; definitions for “flags” bits follow this fragment:
// do {
// USHORT flags;
// USHORT glyphIndex;
// if ( flags & ARG_1_AND_2_ARE_WORDS) {
// (SHORT or FWord) argument1;
// (SHORT or FWord) argument2;
// } else {
// USHORT arg1and2; /* (arg1 << 8) | arg2 */
// }
// if ( flags & WE_HAVE_A_SCALE ) {
// F2Dot14 scale; /* Format 2.14 */
// } else if ( flags & WE_HAVE_AN_X_AND_Y_SCALE ) {
// F2Dot14 xscale; /* Format 2.14 */
// F2Dot14 yscale; /* Format 2.14 */
// } else if ( flags & WE_HAVE_A_TWO_BY_TWO ) {
// F2Dot14 xscale; /* Format 2.14 */
// F2Dot14 scale01; /* Format 2.14 */
// F2Dot14 scale10; /* Format 2.14 */
// F2Dot14 yscale; /* Format 2.14 */
// }
//} while ( flags & MORE_COMPONENTS )
//if (flags & WE_HAVE_INSTR){
// USHORT numInstr
// BYTE instr[numInstr]
//------------------------------------------------------------
return((finalGlyph == null) ? Glyph.Empty : finalGlyph);
}
