add option to use system default caption style

app/src/main/java/com/github/libretube/fragments/PlayerFragment.kt

@@ -23,9 +23,11 @@ import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.view.accessibility.CaptioningManager
 import android.widget.Toast
 import androidx.constraintlayout.motion.widget.MotionLayout
 import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.content.ContextCompat
 import androidx.core.net.toUri
 import androidx.core.os.bundleOf
 import androidx.core.view.isVisible
@@ -78,6 +80,7 @@ import com.google.android.exoplayer2.source.MediaSource
 import com.google.android.exoplayer2.source.MergingMediaSource
 import com.google.android.exoplayer2.source.ProgressiveMediaSource
 import com.google.android.exoplayer2.ui.AspectRatioFrameLayout
+import com.google.android.exoplayer2.ui.CaptionStyleCompat
 import com.google.android.exoplayer2.ui.PlayerNotificationManager
 import com.google.android.exoplayer2.ui.StyledPlayerView
 import com.google.android.exoplayer2.ui.TimeBar
@@ -738,6 +741,14 @@ class PlayerFragment : Fragment() {
             useController = false
             player = exoPlayer
         }
+
+        val useSystemCaptionStyle = PreferenceHelper.getBoolean(requireContext(), "system_caption_style", true)
+        if (useSystemCaptionStyle) {
+            // set the subtitle style
+            val captionStyle = getCaptionStyle()
+            exoPlayerView.subtitleView?.setApplyEmbeddedStyles(captionStyle == CaptionStyleCompat.DEFAULT)
+            exoPlayerView.subtitleView?.setStyle(captionStyle)
+        }
     }
 
     private fun initializePlayerView(view: View, response: Streams) {
@@ -1531,4 +1542,14 @@ class PlayerFragment : Fragment() {
             }
         }
     }
+
+    private fun getCaptionStyle(): CaptionStyleCompat {
+        val captioningManager = ContextCompat.getSystemService(
+            requireContext(),
+            CaptioningManager::class.java
+        )
+        return if (captioningManager == null || !captioningManager.isEnabled) {
+            CaptionStyleCompat.DEFAULT
+        } else CaptionStyleCompat.createFromCaptionStyle(captioningManager.userStyle)
+    }
 }

app/src/main/res/drawable/ic_caption.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="?android:attr/colorControlNormal"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,4L5,4c-1.11,0 -2,0.9 -2,2v12c0,1.1 0.89,2 2,2h14c1.1,0 2,-0.9 2,-2L21,6c0,-1.1 -0.9,-2 -2,-2zM11,11L9.5,11v-0.5h-2v3h2L9.5,13L11,13v1c0,0.55 -0.45,1 -1,1L7,15c-0.55,0 -1,-0.45 -1,-1v-4c0,-0.55 0.45,-1 1,-1h3c0.55,0 1,0.45 1,1v1zM18,11h-1.5v-0.5h-2v3h2L16.5,13L18,13v1c0,0.55 -0.45,1 -1,1h-3c-0.55,0 -1,-0.45 -1,-1v-4c0,-0.55 0.45,-1 1,-1h3c0.55,0 1,0.45 1,1v1z" />
+</vector>

app/src/main/res/values/strings.xml

@@ -249,4 +249,5 @@
     <string name="history_summary">Watch and search history</string>
     <string name="watch_positions_title">Watch positions</string>
     <string name="reset_watch_positions">Reset watch positions</string>
+    <string name="system_caption_style">System caption style</string>
 </resources>

app/src/main/res/xml/appearance_settings.xml

@@ -78,6 +78,16 @@
 
     </PreferenceCategory>
 
+    <PreferenceCategory app:title="@string/player">
+
+        <SwitchPreferenceCompat
+            android:icon="@drawable/ic_caption"
+            app:key="system_caption_style"
+            app:title="@string/system_caption_style"
+            app:defaultValue="true" />
+
+    </PreferenceCategory>
+
     <PreferenceCategory>
 
         <SwitchPreferenceCompat