Update demo transformer app with text overlay demo effect.

Implements milestone 1.4.2 of the [overlays implementation plan](https://docs.google.com/document/d/1EcP2GN8k8N74hHZyD0KTqm9oQo5-W1dZMqIVyqVGtlo/edit#bookmark=id.76uzcie1dg9d)

PiperOrigin-RevId: 493324764

demos/transformer/src/main/java/androidx/media3/demo/transformer/ConfigurationActivity.java

@@ -23,6 +23,7 @@ import android.app.Activity;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.graphics.Color;
 import android.net.Uri;
 import android.os.Bundle;
 import android.view.View;
@@ -89,6 +90,9 @@ public final class ConfigurationActivity extends AppCompatActivity {
   public static final String HSL_ADJUSTMENTS_LIGHTNESS = "hsl_adjustments_lightness";
   public static final String BITMAP_OVERLAY_URI = "bitmap_overlay_uri";
   public static final String BITMAP_OVERLAY_ALPHA = "bitmap_overlay_alpha";
+  public static final String TEXT_OVERLAY_TEXT = "text_overlay_text";
+  public static final String TEXT_OVERLAY_TEXT_COLOR = "text_overlay_text_color";
+  public static final String TEXT_OVERLAY_ALPHA = "text_overlay_alpha";
   public static final int COLOR_FILTER_GRAYSCALE = 0;
   public static final int COLOR_FILTER_INVERTED = 1;
   public static final int COLOR_FILTER_SEPIA = 2;
@@ -143,6 +147,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
     "Overlay logo & timer",
     "Zoom in start",
     "Custom Bitmap Overlay",
+    "Custom Text Overlay",
   };
   private static final ImmutableMap<String, @TransformationRequest.HdrMode Integer>
       HDR_MODE_DESCRIPTIONS =
@@ -153,6 +158,20 @@ public final class ConfigurationActivity extends AppCompatActivity {
                   "Force Interpret HDR as SDR",
                   TransformationRequest.HDR_MODE_EXPERIMENTAL_FORCE_INTERPRET_HDR_AS_SDR)
               .build();
+  private static final ImmutableMap<String, Integer> OVERLAY_COLORS =
+      new ImmutableMap.Builder<String, Integer>()
+          .put("BLACK", Color.BLACK)
+          .put("BLUE", Color.BLUE)
+          .put("CYAN", Color.CYAN)
+          .put("DKGRAY", Color.DKGRAY)
+          .put("GRAY", Color.GRAY)
+          .put("GREEN", Color.GREEN)
+          .put("LTGRAY", Color.LTGRAY)
+          .put("MAGENTA", Color.MAGENTA)
+          .put("RED", Color.RED)
+          .put("WHITE", Color.WHITE)
+          .put("YELLOW", Color.YELLOW)
+          .build();
   private static final String SAME_AS_INPUT_OPTION = "same as input";
   private static final int COLOR_FILTERS_INDEX = 2;
   private static final int RGB_ADJUSTMENTS_INDEX = 4;
@@ -160,6 +179,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
   private static final int CONTRAST_INDEX = 6;
   private static final int PERIODIC_VIGNETTE_INDEX = 7;
   private static final int BITMAP_OVERLAY_INDEX = 11;
+  private static final int TEXT_OVERLAY_INDEX = 12;
   private static final float HALF_DIAGONAL = 1f / (float) Math.sqrt(2);
 
   private @MonotonicNonNull ActivityResultLauncher<Intent> localFilePickerLauncher;
@@ -202,6 +222,9 @@ public final class ConfigurationActivity extends AppCompatActivity {
   private float periodicVignetteOuterRadius;
   private @MonotonicNonNull String bitmapOverlayUri;
   private float bitmapOverlayAlpha;
+  private @MonotonicNonNull String textOverlayText;
+  private int textOverlayTextColor;
+  private float textOverlayAlpha;
 
   @Override
   protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -407,6 +430,9 @@ public final class ConfigurationActivity extends AppCompatActivity {
     bundle.putFloat(PERIODIC_VIGNETTE_OUTER_RADIUS, periodicVignetteOuterRadius);
     bundle.putString(BITMAP_OVERLAY_URI, bitmapOverlayUri);
     bundle.putFloat(BITMAP_OVERLAY_ALPHA, bitmapOverlayAlpha);
+    bundle.putString(TEXT_OVERLAY_TEXT, textOverlayText);
+    bundle.putInt(TEXT_OVERLAY_TEXT_COLOR, textOverlayTextColor);
+    bundle.putFloat(TEXT_OVERLAY_ALPHA, textOverlayAlpha);
     transformerIntent.putExtras(bundle);
 
     @Nullable Uri intentUri;
@@ -539,6 +565,9 @@ public final class ConfigurationActivity extends AppCompatActivity {
       case BITMAP_OVERLAY_INDEX:
         controlBitmapOverlaySettings();
         break;
+      case TEXT_OVERLAY_INDEX:
+        controlTextOverlaySettings();
+        break;
     }
   }
 
@@ -659,6 +688,33 @@ public final class ConfigurationActivity extends AppCompatActivity {
         .show();
   }
 
+  private void controlTextOverlaySettings() {
+    View dialogView = getLayoutInflater().inflate(R.layout.text_overlay_options, /* root= */ null);
+    EditText textEditText = checkNotNull(dialogView.findViewById(R.id.text_overlay_text));
+
+    ArrayAdapter<String> textColorAdapter =
+        new ArrayAdapter<>(/* context= */ this, R.layout.spinner_item);
+    textColorAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
+    Spinner textColorSpinner = checkNotNull(dialogView.findViewById(R.id.text_overlay_text_color));
+    textColorSpinner.setAdapter(textColorAdapter);
+    textColorAdapter.addAll(OVERLAY_COLORS.keySet());
+
+    Slider alphaSlider = checkNotNull(dialogView.findViewById(R.id.text_overlay_alpha_slider));
+    new AlertDialog.Builder(/* context= */ this)
+        .setTitle(R.string.bitmap_overlay_settings)
+        .setView(dialogView)
+        .setPositiveButton(
+            android.R.string.ok,
+            (DialogInterface dialogInterface, int i) -> {
+              textOverlayText = textEditText.getText().toString();
+              String selectedTextColor = String.valueOf(textColorSpinner.getSelectedItem());
+              textOverlayTextColor = checkNotNull(OVERLAY_COLORS.get(selectedTextColor));
+              textOverlayAlpha = alphaSlider.getValue();
+            })
+        .create()
+        .show();
+  }
+
   @RequiresNonNull({
     "removeVideoCheckbox",
     "forceSilentAudioCheckbox",

demos/transformer/src/main/java/androidx/media3/demo/transformer/TransformerActivity.java

@@ -27,6 +27,9 @@ import android.graphics.Color;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
+import android.text.Spannable;
+import android.text.SpannableString;
+import android.text.style.ForegroundColorSpan;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
 import android.view.View;
@@ -55,6 +58,7 @@ import androidx.media3.effect.RgbAdjustment;
 import androidx.media3.effect.RgbFilter;
 import androidx.media3.effect.RgbMatrix;
 import androidx.media3.effect.SingleColorLut;
+import androidx.media3.effect.TextOverlay;
 import androidx.media3.exoplayer.ExoPlayer;
 import androidx.media3.exoplayer.audio.SilenceSkippingAudioProcessor;
 import androidx.media3.exoplayer.audio.SonicAudioProcessor;
@@ -501,13 +505,30 @@ public final class TransformerActivity extends AppCompatActivity {
                   bundle.getFloat(
                       ConfigurationActivity.BITMAP_OVERLAY_ALPHA, /* defaultValue= */ 1))
               .build();
-
       BitmapOverlay bitmapOverlay =
           BitmapOverlay.createStaticBitmapOverlay(
               Uri.parse(checkNotNull(bundle.getString(ConfigurationActivity.BITMAP_OVERLAY_URI))),
               overlaySettings);
       effects.add(new OverlayEffect(ImmutableList.of(bitmapOverlay)));
     }
+    if (selectedEffects[12]) {
+      OverlaySettings overlaySettings =
+          new OverlaySettings.Builder()
+              .setAlpha(
+                  bundle.getFloat(ConfigurationActivity.TEXT_OVERLAY_ALPHA, /* defaultValue= */ 1))
+              .build();
+      SpannableString overlayText =
+          new SpannableString(
+              checkNotNull(bundle.getString(ConfigurationActivity.TEXT_OVERLAY_TEXT)));
+      overlayText.setSpan(
+          new ForegroundColorSpan(bundle.getInt(ConfigurationActivity.TEXT_OVERLAY_TEXT_COLOR)),
+          /* start= */ 0,
+          overlayText.length(),
+          Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+      TextOverlay textOverlay = TextOverlay.createStaticTextOverlay(overlayText, overlaySettings);
+      // TODO(227625365): use the same OverlayEffect object for bitmap and text overlays.
+      effects.add(new OverlayEffect(ImmutableList.of(textOverlay)));
+    }
     return effects.build();
   }
 

demos/transformer/src/main/res/layout/text_overlay_options.xml

@@ -0,0 +1,69 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2022 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  xmlns:tools="http://schemas.android.com/tools"
+  android:layout_width="fill_parent"
+  android:layout_height="fill_parent"
+  tools:context=".ConfigurationActivity">
+
+  <TableLayout
+    android:layout_width="fill_parent"
+    android:layout_height="wrap_content"
+    android:stretchColumns="1"
+    android:layout_marginTop="32dp"
+    android:measureWithLargestChild="true"
+    android:paddingLeft="24dp"
+    android:paddingRight="12dp"
+    app:layout_constraintEnd_toEndOf="parent"
+    app:layout_constraintStart_toStartOf="parent"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintBottom_toBottomOf="parent">
+    <TableRow
+      android:layout_weight="1"
+      android:gravity="center_vertical" >
+      <TextView
+        android:text="@string/overlay_text" />
+      <EditText
+        android:id="@+id/text_overlay_text"
+        android:inputType="textMultiLine"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content" />
+    </TableRow>
+    <TableRow
+      android:layout_weight="1"
+      android:gravity="center_vertical" >
+      <TextView
+        android:text="@string/overlay_text_color"/>
+      <Spinner
+        android:id="@+id/text_overlay_text_color"
+        android:layout_gravity="right|center_vertical"
+        android:gravity="right" />
+    </TableRow>
+    <TableRow
+      android:layout_weight="1"
+      android:gravity="center_vertical" >
+      <TextView android:text="@string/overlay_alpha" />
+      <com.google.android.material.slider.Slider
+        android:id="@+id/text_overlay_alpha_slider"
+        android:valueFrom="0"
+        android:value="1"
+        android:valueTo="1"
+        android:layout_gravity="right|center_vertical"/>
+    </TableRow>
+  </TableLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>

demos/transformer/src/main/res/values/strings.xml

@@ -70,4 +70,7 @@
   <string name="overlay_alpha">Alpha</string>
   <string name="overlay_uri">Uri</string>
   <string name="bitmap_overlay_settings">Specify bitmap overlay settings</string>
+  <string name="overlay_text">Text</string>
+  <string name="overlay_text_color">Text color</string>
+  <string name="text_overlay_settings">Specify text overlay settings</string>
 </resources>