From 8167c115e34e6b206a8446d98ce22c574d8a1584 Mon Sep 17 00:00:00 2001
From: pekingme <8545955+pekingme@users.noreply.github.com>
Date: Fri, 19 Jan 2024 22:44:33 +0000
Subject: [PATCH] [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 97f18a37a43ac4ce784b3bee6ac6b5ab91e3fcae)
---
 .../progressindicator/BaseProgressIndicator.java       |  2 +-
 .../progressindicator/CircularDrawingDelegate.java     | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/java/com/google/android/material/progressindicator/BaseProgressIndicator.java b/lib/java/com/google/android/material/progressindicator/BaseProgressIndicator.java
index f02480a6de9..13351b0ff2d 100644
--- a/lib/java/com/google/android/material/progressindicator/BaseProgressIndicator.java
+++ b/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();
     }
   }
diff --git a/lib/java/com/google/android/material/progressindicator/CircularDrawingDelegate.java b/lib/java/com/google/android/material/progressindicator/CircularDrawingDelegate.java
index be838a1e91c..4a89f93371c 100644
--- a/lib/java/com/google/android/material/progressindicator/CircularDrawingDelegate.java
+++ b/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(