onScaleStart method
Handle the start of a gesture. All of pan, scale, and rotate are handled with GestureDetector's scale gesture.
Implementation
@protected
void onScaleStart(ScaleStartDetails details) {
resetAnimation();
gestureType = null;
currentAxis = null;
scaleStart = transformationController!.value.getScaleOnZAxis();
referenceFocalPoint = transformationController!.toScene(
details.localFocalPoint,
);
rotationStart = currentRotation;
}