hexToPixel method
将六边形坐标转换为像素坐标(中心点)
Implementation
Offset hexToPixel(HexCoordinate hex) {
final m = orientation;
final x = (m.f0 * hex.x + m.f1 * hex.z) * size;
final y = (m.f2 * hex.x + m.f3 * hex.z) * size;
return Offset(x + origin.dx, y + origin.dy);
}