public static void ComposeGlyphs(int glyphIndex, int startPoint, ref Matrix3x2 transform, List<PointF> basePoints, List<int> baseContours, BaseGlyph[] glyphTable)
{
var glyph = glyphTable[glyphIndex];
var simple = glyph as SimpleGlyph;
if (simple != null)
{
foreach (var endpoint in simple.ContourEndpoints)
baseContours.Add(endpoint + startPoint);
foreach (var point in simple.Points)
basePoints.Add(new PointF(Vector2.TransformNormal((Vector2)point, transform), point.Type));
}
else
{
// otherwise, we have a composite glyph
var composite = (CompositeGlyph)glyph;
foreach (var subglyph in composite.Subglyphs)
{
// if we have a scale, update the local transform
var local = transform;
bool haveScale = (subglyph.Flags & (CompositeGlyphFlags.HaveScale | CompositeGlyphFlags.HaveXYScale | CompositeGlyphFlags.HaveTransform)) != 0;
if (haveScale)
local = transform * subglyph.Transform;
// recursively compose the subglyph into our lists
int currentPoints = basePoints.Count;
ComposeGlyphs(subglyph.Index, currentPoints, ref local, basePoints, baseContours, glyphTable);
// calculate the offset for the subglyph. we have to do offsetting after composing all subglyphs,
// because we might need to find the offset based on previously composed points by index
Vector2 offset;
if ((subglyph.Flags & CompositeGlyphFlags.ArgsAreXYValues) != 0)
{
offset = (Vector2)new Point((FUnit)subglyph.Arg1, (FUnit)subglyph.Arg2);
if (haveScale && (subglyph.Flags & CompositeGlyphFlags.ScaledComponentOffset) != 0)
offset = Vector2.TransformNormal(offset, local);
else
offset = Vector2.TransformNormal(offset, transform);
// if the RoundXYToGrid flag is set, round the offset components
if ((subglyph.Flags & CompositeGlyphFlags.RoundXYToGrid) != 0)
offset = new Vector2((float)Math.Round(offset.X), (float)Math.Round(offset.Y));
}
else
{
// if the offsets are not given in FUnits, then they are point indices
// in the currently composed base glyph that we should match up
var p1 = basePoints[(int)((uint)subglyph.Arg1 + startPoint)];
var p2 = basePoints[(int)((uint)subglyph.Arg2 + currentPoints)];
offset = p1.P - p2.P;
}
// translate all child points
if (offset != Vector2.Zero)
{
for (int i = currentPoints; i < basePoints.Count; i++)
basePoints[i] = basePoints[i].Offset(offset);
}
}
}
}
public static void ReadGlyph(
DataReader reader, int glyphIndex, int recursionDepth,
BaseGlyph[] glyphTable, uint glyfOffset, uint glyfLength, uint* loca
)
{
// check if this glyph has already been loaded; this can happen
// if we're recursively loading subglyphs as part of a composite
if (glyphTable[glyphIndex] != null)
return;
// prevent bad font data from causing infinite recursion
if (recursionDepth > MaxRecursion)
throw new InvalidFontException("Bad font data; infinite composite recursion.");
// check if this glyph doesn't have any actual data
GlyphHeader header;
var offset = loca[glyphIndex];
if ((glyphIndex < glyphTable.Length - 1 && offset == loca[glyphIndex + 1]) || offset >= glyfLength)
{
// this is an empty glyph, so synthesize a header
header = default(GlyphHeader);
}
else
{
// seek to the right spot and load the header
reader.Seek(glyfOffset + loca[glyphIndex]);
header = new GlyphHeader
{
ContourCount = reader.ReadInt16BE(),
MinX = reader.ReadInt16BE(),
MinY = reader.ReadInt16BE(),
MaxX = reader.ReadInt16BE(),
MaxY = reader.ReadInt16BE()
};
if (header.ContourCount < -1 || header.ContourCount > MaxContours)
throw new InvalidFontException("Invalid number of contours for glyph.");
}
if (header.ContourCount > 0)
{
// positive contours means a simple glyph
glyphTable[glyphIndex] = ReadSimpleGlyph(reader, header.ContourCount);
}
else if (header.ContourCount == -1)
{
// -1 means composite glyph
var composite = ReadCompositeGlyph(reader);
var subglyphs = composite.Subglyphs;
// read each subglyph recrusively
for (int i = 0; i < subglyphs.Length; i++)
ReadGlyph(reader, subglyphs[i].Index, recursionDepth + 1, glyphTable, glyfOffset, glyfLength, loca);
glyphTable[glyphIndex] = composite;
}
else
{
// no data, so synthesize an empty glyph
glyphTable[glyphIndex] = new SimpleGlyph
{
Points = new Point[0],
ContourEndpoints = new int[0]
};
}
// save bounding box
var glyph = glyphTable[glyphIndex];
glyph.MinX = header.MinX;
glyph.MinY = header.MinY;
glyph.MaxX = header.MaxX;
glyph.MaxY = header.MaxY;
}
