onPanStart method
Implementation
void onPanStart(DragStartDetails details) {
final localPosition = details.localPosition;
if (_isPointInBounds(localPosition)) {
_hasPanned = true;
if (!_isDrawing) {
_isDrawing = true;
_currentStroke = [localPosition];
_currentPath = Path();
}
if (_currentPath.getBounds().isEmpty) {
_currentPath.moveTo(localPosition.dx, localPosition.dy);
}
notifyListeners();
}
}