[ProgressIndicator] Improved the smoothness of the animation when ina…

…ctive track's ends are close.

Resolves #4124

PiperOrigin-RevId: 621620538

lib/java/com/google/android/material/progressindicator/CircularDrawingDelegate.java

@@ -265,14 +265,20 @@ private void drawArc(
  }
 
  float displayedCornerRadiusInDegree = (float) toDegrees(displayedCornerRadius / adjustedRadius);
-
- if (startFraction == 0 && arcFraction >= 1 - ROUND_CAP_RAMP_DOWN_THRESHHOLD) {
+ float arcFractionOverRoundCapThreshold = arcFraction - (1 - ROUND_CAP_RAMP_DOWN_THRESHHOLD);
+ if (arcFractionOverRoundCapThreshold >= 0) {
  // Increases the arc length to hide the round cap at the ends when the active indicator is
  // forming a full circle.
- arcFraction +=
- (arcFraction - (1 - ROUND_CAP_RAMP_DOWN_THRESHHOLD))
- * (2 * displayedCornerRadiusInDegree / 360)
+ float increasedArcFraction =
+ arcFractionOverRoundCapThreshold
+ * displayedCornerRadiusInDegree
+ / 180
  / ROUND_CAP_RAMP_DOWN_THRESHHOLD;
+ arcFraction += increasedArcFraction;
+ // Offsets the start fraction to make the inactive track's ends connect at 0%.
+ if (!shouldDrawActiveIndicator) {
+ startFraction -= increasedArcFraction / 2;
+ }
  }
 
  // Scale start and arc fraction for ESCAPE animation.