From 7674e12ea818793fe654f7691941f0bdc97c75f3 Mon Sep 17 00:00:00 2001
From: pubiqq <serj.ese@gmail.com>
Date: Thu, 2 Nov 2023 13:58:38 +0000
Subject: [PATCH] [CollapsingToolbarLayout] Fix text shadow fading when
 transitioning between expanded and collapsed states

Resolves https://github.com/material-components/material-components-android/pull/3641

GIT_ORIGIN_REV_ID=7243f7a2f09b04caceec488443b1652a8ffef961
PiperOrigin-RevId: 578838845
---
 .../android/material/internal/CollapsingTextHelper.java   | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/java/com/google/android/material/internal/CollapsingTextHelper.java b/lib/java/com/google/android/material/internal/CollapsingTextHelper.java
index 5194ed8ec72..fa200df1292 100644
--- a/lib/java/com/google/android/material/internal/CollapsingTextHelper.java
+++ b/lib/java/com/google/android/material/internal/CollapsingTextHelper.java
@@ -672,6 +672,14 @@ private void calculateOffsets(final float fraction) {
       int textAlpha = (int) (calculateFadeModeTextAlpha(fraction) * originalAlpha);
 
       textPaint.setAlpha(textAlpha);
+      // Workaround for API 31(+). Applying the shadow color for the painted text.
+      if (VERSION.SDK_INT >= VERSION_CODES.S) {
+        textPaint.setShadowLayer(
+            currentShadowRadius,
+            currentShadowDx,
+            currentShadowDy,
+            MaterialColors.compositeARGBWithAlpha(currentShadowColor, textPaint.getAlpha()));
+      }
     }
 
     ViewCompat.postInvalidateOnAnimation(view);