private void DrawSection(Graphics g, PointBuffer points, int start, int length)
{
if (length > 1) // DrawLines crashes if there isn't at least two points
{
Point[] _buffer;
_buffer = ArrayPool <Point> .Shared.Allocate(length);
points.CopyTo(start, _buffer, 0, length);
g.DrawLines(_tailPen, _buffer);
ArrayPool <Point> .Shared.Free(_buffer);
}
}
private void DrawStrandTail(Graphics g, PointBuffer points)
{
if (points.Size > 1)
{
// don't do this!
//g.DrawLines(_bodyPen, points.ToArray());
if (!this.HasSplitResults(points))
{
Point[] _buffer;
// this isn't great, but as Graphics.DrawLines
// isn't enlightened enough to take a start and length,
// we copy the buffer out of the CircularBuffer into an
// existing byte array so in theory we aren't allocating
// an array over and over again
_buffer = ArrayPool <Point> .Shared.Allocate(points.Size);
points.CopyTo(_buffer);
g.DrawLines(_tailPen, _buffer);
ArrayPool <Point> .Shared.Free(_buffer);
}
else
{
int start;
Point previous;
Point current;
// if we've wrapped the playing field, I can't just
// call DrawLines with the entire buffer as we'll get
// lines drawn across the entire playing field, so
// instead I need to break it down into smaller buffers
start = 0;
previous = points.PeekAt(0);
for (int i = 1; i < points.Size; i++)
{
current = points.PeekAt(i);
if (Geometry.GetDistance(previous, current) > 1)
{
// here we have a split, so let us grab a subset of
// the buffer and draw our lines
this.DrawSection(g, points, start, i - start);
start = i;
}
previous = current;
}
if (start < points.Size)
{
this.DrawSection(g, points, start, points.Size - start);
}
}
}
}
