//绘制实心菱形
private static void DrawSolidDiamond(PointF[] p, Graphics g, Color c, Size sz)
{
PointF[] p2 = new PointF[5];
RectangleF recf = new RectangleF(0, 0, sz.Width, sz.Height);
LinearGradientBrush bsh = new LinearGradientBrush(recf, c, c, 0.0f);
bsh.RotateTransform(45);
float a = (float)Math.Sqrt(sz.Width * sz.Width + sz.Height * sz.Height);
float halfa = a * 0.5f;
for (int i = 0; i < p.Length; i++)
{
p2[0].X = p[i].X;
p2[0].Y = p[i].Y - halfa;
p2[1].X = p[i].X + halfa;
p2[1].Y = p[i].Y;
p2[2].X = p[i].X;
p2[2].Y = p[i].Y + halfa;
p2[3].X = p[i].X - halfa;
p2[3].Y = p[i].Y;
p2[4] = p2[0];
g.FillPolygon(bsh, p2);
}
}