Allow bounce easings along a path to return a position outside of the path

[idlewan]

Don't clamp interpolated distance along path to 'progress' value between 0 and 1.

Bounce in / Bounce out easings can transform the progress to negative values or values higher than 1. getPosTan unfortunately clamps the input to be between 0 and 1, so we need to handle the t < 0 and t > 1 cases separately.

This is for the same issue I helped fix in the flutter library as well here: xvrh/lottie-flutter#330

Expected result (both bounce-in and bounce out) along linear and curved paths:

android-bounce-easings.mp4

[github-actions]

Snapshot Tests
API 23: Report Diff
API 31: Report Diff

[gpeal]

Thanks for doing this. I didn't know you were a part of the lottielab team!

[fmalita]

Nit: since getPosTan() already clamps to end points, you could consolidate some calls

float distance =  keyframeProgress * length;
pathMeasure.getPosTan(distance, pos, tangent);
point.set(pos[0], pos[1]);

if (distance < 0) {
  point.offset(tangent[0] * distance, tangent[1] * distance);
} else if (distance > length) {
  point.offset(tangent[0] * (distance - length), tangent[1] * (distance - length));
}

[gpeal]

Thanks @fmalita
@idlewan want to put up another PR for this or would you like me to?

[idlewan]

Sure thing, thanks for proposing a cleaner version!
Here's the PR: #2459