in shimmer/src/main/java/com/facebook/shimmer/Shimmer.java [129:135]
void updateBounds(int viewWidth, int viewHeight) {
int magnitude = Math.max(viewWidth, viewHeight);
double rad = Math.PI / 2f - Math.toRadians(tilt % 90f);
double hyp = magnitude / Math.sin(rad);
int padding = 3 * Math.round((float) (hyp - magnitude) / 2f);
bounds.set(-padding, -padding, width(viewWidth) + padding, height(viewHeight) + padding);
}