paintAccent method
Implementation
void paintAccent(Canvas canvas) {
canvas.save();
canvas.clipPath(outerPath);
var virtualBoxPath = Path.combine(
PathOperation.difference,
outerPath,
innerPath.shift(
Offset(-alignment.x * accentShift, -alignment.y * accentShift)));
canvas.drawPath(virtualBoxPath, paintObject);
canvas.restore();
}