CustomPainter Path extra line on canvas - dart

Question

I am using CustomPainter where I need to draw line
class ShapesPainter extends CustomPainter {
#override
void paint(Canvas canvas, Size size) {
final Paint firstPaint = Paint();
firstPaint.color = const Color.fromARGB(255, 236, 0, 140);
final Path firstPath = Path();
firstPath.lineTo(size.width, 0);
firstPath.lineTo(0, size.height * 0.10);
firstPath.close();
canvas.drawShadow(firstPath, Colors.black87, 2.0, false);
canvas.drawPath(firstPath, firstPaint);
}
}
I need to leave margin around the screen so I am using margin in container:
........
Container(
color: Colors.white,
margin:
EdgeInsets.only(top: 60.0, bottom: 20.0, left: 15.0, right: 15.0),
child: Container(
child: CustomPaint(
painter: ShapesPainter(),
child: Container(
.......
I need to draw a shadow under my custom path which I used anvas.drawShadow method in my build Widget, But there is a little shadow also coming over the left side, Please see the image below I pointed an error, here is pointing arrow to small shadow:

Answer 1

As I couldn't find any solution for the canvas.drawShadow effect on Path, I just created another Path() on top of the shadowed path, which solved the issue, but its kind of a hack.
final Path firstPathb = Path();
firstPathHide.lineTo(size.width, 0);
firstPathHide.lineTo(-10.0, size.height * 0.10);
firstPathHide.close();
canvas.drawPath(firstPathHide, firstPaint);