usesSuperviewShadowLayerAsMask migration

tl;dr: If you are adding ripples to views with custom layer.shadowPath values, please disable usesSuperviewShadowLayerAsMask and assign an explicit layer mask to the ripple view if needed instead. usesSuperviewShadowLayerAsMask will eventually be disabled by default and then deleted.

MDCRippleView currently implements a convenience behavior that will inherit its parent view‘s layer.shadowPath as the mask of the ripple view itself. This works for the general case where the ripple view’s frame equals the bounds of its super view, but behaves unexpectedly for any other frame of the ripple view.

Due to the brittleness of this behavior, a new migration property, usesSuperviewShadowLayerAsMask, has been added that will allow you to disable this behavior in favor of a more explicit determination of the ripple's layer mask.

Example usage:

Swift

// During initialization:
rippleView.usesSuperviewShadowLayerAsMask = false

// Simple example of applying a mask to the ripple view using the ripple view's bounds:
let rippleViewMask = CAShapeLayer()
rippleViewMask.path = UIBezierPath(rect: rippleView.bounds).cgPath
rippleView.layer.mask = rippleViewMask

Objective-C

// During initialization:
rippleView.usesSuperviewShadowLayerAsMask = NO;

// Simple example of applying a mask to the ripple view using the ripple view's bounds:
CAShapeLayer *rippleViewMask = [[CAShapeLayer alloc] init];
rippleViewMask.path = [UIBezierPath bezierPathWithRect:rippleView.bounds].CGPath;
rippleView.layer.mask = rippleViewMask;

Please consider disabling usesSuperviewShadowLayerAsMask if you are creating MDCRippleView instances. The property will be disabled by default in the future and then deprecated.