[ProgressIndicator] Fixed the rounded ends overlapping bug with semi-…

…transparent track/indicator color in Circular default style.

Workaround is applied by using the Cap.ROUND when corner radius is half of the track thickness (the case for M3 default Circular style). It doesn't fix the overlap for smaller corner radius with semi-transparent color.

PiperOrigin-RevId: 599942498
(cherry picked from commit 97f18a3)

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

@@ -548,6 +548,7 @@ public int getTrackThickness() {
  public void setTrackThickness(@Px int trackThickness) {
  if (spec.trackThickness != trackThickness) {
  spec.trackThickness = trackThickness;
+ spec.trackCornerRadius = min(spec.trackCornerRadius, spec.trackThickness / 2);
  requestLayout();
  }
  }
@@ -634,7 +635,6 @@ public int getTrackCornerRadius() {
  public void setTrackCornerRadius(@Px int trackCornerRadius) {
  if (spec.trackCornerRadius != trackCornerRadius) {
  spec.trackCornerRadius = min(trackCornerRadius, spec.trackThickness / 2);
- spec.validateSpec();
  invalidate();
  }
  }

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

@@ -37,6 +37,8 @@ final class CircularDrawingDelegate extends DrawingDelegate<CircularProgressIndi
  private float displayedTrackThickness;
  private float displayedCornerRadius;
  private float adjustedRadius;
+ // For full round ends, the stroke ROUND cap is used to prevent artifacts like (b/319309456).
+ private boolean useStrokeCap;
 
  // This will be used in the ESCAPE hide animation. The start and end fraction in track will be
  // scaled by this fraction with a pivot of 1.0f.
@@ -105,6 +107,7 @@ void adjustCanvas(
  -outerRadiusWithInset, -outerRadiusWithInset, outerRadiusWithInset, outerRadiusWithInset);
 
  // These are used when drawing the indicator and track.
+ useStrokeCap = spec.trackThickness / 2 <= spec.trackCornerRadius;
  displayedTrackThickness = spec.trackThickness * trackThicknessFraction;
  displayedCornerRadius = spec.trackCornerRadius * trackThicknessFraction;
  adjustedRadius = (spec.indicatorSize - spec.trackThickness) / 2f;
@@ -145,7 +148,6 @@ void fillIndicator(
 
  // Sets up the paint.
  paint.setStyle(Style.STROKE);
- paint.setStrokeCap(Cap.BUTT);
  paint.setAntiAlias(true);
  paint.setColor(color);
  paint.setStrokeWidth(displayedTrackThickness);
@@ -189,10 +191,14 @@ void fillIndicator(
 
  // Draws the indicator arc without rounded corners.
  RectF arcBound = new RectF(-adjustedRadius, -adjustedRadius, adjustedRadius, adjustedRadius);
+ paint.setStrokeCap(useStrokeCap ? Cap.ROUND : Cap.BUTT);
  canvas.drawArc(arcBound, startDegree, arcDegree, false, paint);
 
  // Draws rounded corners if needed.
- if (displayedCornerRadius > 0 && Math.abs(arcDegree) > 0 && Math.abs(arcDegree) < 360) {
+ if (!useStrokeCap
+ && displayedCornerRadius > 0
+ && Math.abs(arcDegree) > 0
+ && Math.abs(arcDegree) < 360) {
  paint.setStyle(Style.FILL);
  drawRoundedEnd(canvas, paint, displayedTrackThickness, displayedCornerRadius, startDegree);
  drawRoundedEnd(