Flutter - how do I rotate an object on a CustomPainter canvas? - flutter

Question

How do you rotate an object drawn on a canvas in Flutter (not the whole canvas, just the object)?
The following does not work. Error is: This expression has a type of 'void' so its value can't be used.
Transform.rotate(
angle: pi,
child: canvas.drawPath(
getTrianglePath(Offset(secondhandX, secondhandY)),
secondhandBrush));
Here is the full code:
// imports omitted
class TimerDialPainter extends CustomPainter {
Path getTrianglePath(Offset position) {
return Path()
..moveTo(position.dx - 20, position.dy - 20)
..lineTo(position.dx + 40, position.dy + 40)
..lineTo(position.dx - 20, position.dy + 40)
..lineTo(position.dx - 20, position.dy - 20);
}
#override
void paint(Canvas canvas, Size size) {
int centerX = size.width / 2;
int centerY = size.height / 2;
int secondsArc = 60;
Paint countBrush = Paint()
..color = (Colors.red)
..style = PaintingStyle.fill
..strokeWidth = 3;
var secondhandX = centerX + 80 * cos(secondsArc * pi / 180);
var secondhandY = centerY + 80 * sin(secondsArc * pi / 180);
Transform.rotate(
angle: pi/3,
child: canvas.drawPath(
getTrianglePath(Offset(secondhandX, secondhandY)),
countBrush));
} //I feel this is not a right place to solve this??
}
#override
bool shouldRepaint(covariant CustomPainter oldDelegate) {
return true;
}
}

Answer 1

Try rotating the canvas and paint it. Then rotate it back to previous value
#override
void paint(Canvas canvas, Size size) {
double centerX = size.width / 2;
double centerY = size.height / 2;
int secondsArc = 60;
Paint countBrush = Paint()
..color = (Colors.red)
..style = PaintingStyle.fill
..strokeWidth = 3;
num secondhandX = centerX + 80 * cos(secondsArc * pi / 180);
num secondhandY = centerY + 80 * sin(secondsArc * pi / 180);
canvas.rotate(40);
canvas.drawPath(
getTrianglePath(Offset(secondhandX.toDouble(), secondhandY.toDouble())),
countBrush);
canvas.rotate(0);
}