private bool SerializeGlyf(ushort indexFormat)
{
Debug.Assert(_glyphs != null && _glyphs.Length != 0);
Debug.Assert(indexFormat == 0 || indexFormat == 1);
uint locaOffset = 0;
var glyphWriter = new WoffWriter();
uint maxCapacity = 5 * _maxNumPoints; // Size without the application of packing.
var pointsWriter = new WoffIndexer((int)maxCapacity); // Created here for reuse
int glyphCount = _glyphs.Length;
for (ushort i = 0; i < glyphCount; i++)
{
var glyph = _glyphs[i];
uint glyphSize = 0;
pointsWriter.Offset = 0; // Reset the offset, it is non-resizable buffer (size is fixed).
if (glyph.Serialize(glyphWriter, pointsWriter, out glyphSize) == false)
{
Trace.TraceError("Glyph Serialization Error: Glyph Index = {0}.", glyph.GlyphIndex);
return(false);
}
_glyphsLocations.Add(locaOffset);
locaOffset += glyphSize;
}
var glyphBuffer = glyphWriter.GetBuffer();
_woffDir.OrigTable = glyphBuffer;
_woffDir.OrigLength = (uint)glyphBuffer.Length;
return(true);
}
/// <summary>
/// This function stores just the point data. Coordinates packing algorithm based on the Google/woff2 sources.
/// </summary>
/// <param name="writer"></param>
/// <param name="pointsCapacity"></param>
/// <param name="pointsLength"></param>
/// <returns>Returns true on success.</returns>
private bool PackPoints(WoffIndexer writer, uint pointsCapacity, ref uint pointsLength)
{
uint flagOffset = 0;
int lastFlag = -1;
int repeatCount = 0;
int lastX = 0;
int lastY = 0;
uint xBytes = 0;
uint yBytes = 0;
int nPoints = _contours.Count;
for (int i = 0; i < nPoints; ++i)
{
var point = _contours[i];
int flag = point.IsOnCurve ? kGlyfOnCurve : 0;
int dx = point.X - lastX;
int dy = point.Y - lastY;
if (dx == 0)
{
flag |= kGlyfThisXIsSame;
}
else if (dx > -256 && dx < 256)
{
flag |= kGlyfXShort | (dx > 0 ? kGlyfThisXIsSame : 0);
xBytes += 1;
}
else
{
xBytes += 2;
}
if (dy == 0)
{
flag |= kGlyfThisYIsSame;
}
else if (dy > -256 && dy < 256)
{
flag |= kGlyfYShort | (dy > 0 ? kGlyfThisYIsSame : 0);
yBytes += 1;
}
else
{
yBytes += 2;
}
if (flag == lastFlag && repeatCount != 255)
{
writer[flagOffset - 1] |= kGlyfRepeat;
repeatCount++;
}
else
{
if (repeatCount != 0)
{
if ((flagOffset >= pointsCapacity))
{
return(false);
}
writer[flagOffset++] = (byte)repeatCount;
}
if ((flagOffset >= pointsCapacity))
{
return(false);
}
writer[flagOffset++] = (byte)flag;
repeatCount = 0;
}
lastX = point.X;
lastY = point.Y;
lastFlag = flag;
}
if (repeatCount != 0)
{
if ((flagOffset >= pointsCapacity))
{
return(false);
}
writer[flagOffset++] = (byte)repeatCount;
}
uint xyBytes = xBytes + yBytes;
if ((xyBytes < xBytes || flagOffset + xyBytes < flagOffset || flagOffset + xyBytes > pointsCapacity))
{
return(false);
}
uint xOffset = flagOffset;
uint yOffset = flagOffset + xBytes;
lastX = 0;
lastY = 0;
for (int i = 0; i < nPoints; ++i)
{
int dx = _contours[i].X - lastX;
if (dx == 0)
{
// pass
}
else if (dx > -256 && dx < 256)
{
writer[xOffset++] = (byte)Math.Abs(dx);
}
else
{
// will always fit for valid input, but overflow is harmless
writer.WriteInt16(dx, ref xOffset);
}
lastX += dx;
int dy = _contours[i].Y - lastY;
if (dy == 0)
{
// pass
}
else if (dy > -256 && dy < 256)
{
writer[yOffset++] = (byte)Math.Abs(dy);
}
else
{
writer.WriteInt16(dy, ref yOffset);
}
lastY += dy;
}
pointsLength = yOffset;
return(true);
}
public bool Serialize(WoffWriter writer, WoffIndexer pointsWriter, out uint glyphSize)
{
glyphSize = 0;
if (writer == null)
{
return(false);
}
uint startOffset = writer.Offset;
// 1. Write the Glyph Header
writer.WriteInt16(_numContours); // int16 numberOfContours for number of contours: >= 0 is simple glyph, < 0 composite glyph.
writer.WriteInt16(_xMin); // int16 xMin Minimum x for coordinate data.
writer.WriteInt16(_yMin); // int16 yMin Minimum y for coordinate data.
writer.WriteInt16(_xMax); // int16 xMax Maximum x for coordinate data.
writer.WriteInt16(_yMax); // int16 yMax Maximum y for coordinate data.
// 2. Write the Simple Glyph Description, if applicable
if (_glyphType == WoffGlyphType.Simple)
{
// uint16 endPtsOfContours[numberOfContours]
// Array of point indices for the last point of each contour, in increasing numeric order.
Debug.Assert(_endPtsOfContours != null && _endPtsOfContours.Length == _numContours);
if (_endPtsOfContours == null || _endPtsOfContours.Length != _numContours)
{
Debug.Assert(false, "Invalid condition.");
return(false);
}
for (short i = 0; i < _numContours; i++)
{
writer.WriteUInt16(_endPtsOfContours[i]);
}
// uint16 instructionLength Total number of bytes for instructions.
// If instructionLength is zero, no instructions are present for this glyph,
// and this field is followed directly by the flags field.instructionLength
writer.WriteUInt16(_instructionLength);
// uint8 instructions[instructionLength] Array of instruction byte code for the glyph.
if (_instructionLength != 0)
{
Debug.Assert(_instructions != null && _instructions.Length == _instructionLength);
if (_instructions == null || _instructions.Length != _instructionLength)
{
Debug.Assert(false, "Invalid condition.");
return(false);
}
writer.Write(_instructions);
}
// Pack the points
Debug.Assert(_numPoints == _contours.Count);
int pointsCapacity = 5 * _numPoints; // Size without the application of packing.
if (pointsWriter == null)
{
pointsWriter = new WoffIndexer(pointsCapacity);
}
else
{
pointsWriter.Offset = 0;
}
uint pointsLength = 0;
if (PackPoints(pointsWriter, (uint)pointsCapacity, ref pointsLength) == false)
{
Debug.Assert(false, "Invalid condition.");
return(false);
}
// Serialize the points...
writer.Write(pointsWriter.GetBuffer(), 0, (int)pointsLength);
}
// Write the Simple Glyph Description, if applicable
else if (_glyphType == WoffGlyphType.Composite)
{
Debug.Assert(_componentLength != 0);
Debug.Assert(_components != null && _componentLength == _components.Length);
if (_componentLength == 0 || _components == null || _componentLength != _components.Length)
{
Debug.Assert(false, "Invalid condition.");
return(false);
}
// Serialize the Composite Glyph data...
writer.Write(_components, 0, _componentLength);
}
// NOTE: Without the padding the serialization of the glyph fails!
var padBytesLength = WoffBuffer.CalcPadBytes((int)writer.Offset, 4);
if (padBytesLength > 0)
{
var paddingBuffer = new byte[4];
writer.Write(paddingBuffer, 0, padBytesLength);
}
uint endOffset = writer.Offset;
if (endOffset <= startOffset)
{
Debug.Assert(false, "Invalid condition.");
return(false);
}
glyphSize = endOffset - startOffset;
return(true);
}