Add vertical text support to TtmlDecoder

I needed to use Cue.Builder instead of just SpannableStringBuilder for
the regionOutput values, so I could attach the vertical info where
appropriate (since this is a property of the Cue, not a span).

PiperOrigin-RevId: 290709294

library/core/src/main/java/com/google/android/exoplayer2/text/Cue.java

@@ -497,12 +497,36 @@ public final class Cue {
       return this;
     }
 
-    /** Sets the cue image. */
+    /**
+     * Gets the cue text.
+     *
+     * @see Cue#text
+     */
+    @Nullable
+    public CharSequence getText() {
+      return text;
+    }
+
+    /**
+     * Sets the cue image.
+     *
+     * @see Cue#bitmap
+     */
     public Builder setBitmap(Bitmap bitmap) {
       this.bitmap = bitmap;
       return this;
     }
 
+    /**
+     * Gets the cue image.
+     *
+     * @see Cue#bitmap
+     */
+    @Nullable
+    public Bitmap getBitmap() {
+      return bitmap;
+    }
+
     /**
      * Sets the alignment of the cue text within the cue box.
      *
@@ -515,6 +539,16 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the alignment of the cue text within the cue box, or null if the alignment is undefined.
+     *
+     * @see Cue#textAlignment
+     */
+    @Nullable
+    public Alignment getTextAlignment() {
+      return textAlignment;
+    }
+
     /**
      * Sets the position of the {@code lineAnchor} of the cue box within the viewport in the
      * direction orthogonal to the writing direction.
@@ -561,6 +595,26 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the position of the {@code lineAnchor} of the cue box within the viewport in the
+     * direction orthogonal to the writing direction.
+     *
+     * @see Cue#line
+     */
+    public float getLine() {
+      return line;
+    }
+
+    /**
+     * Gets the type of the value of {@link #getLine()}.
+     *
+     * @see Cue#lineType
+     */
+    @LineType
+    public int getLineType() {
+      return lineType;
+    }
+
     /**
      * Sets the cue box anchor positioned by {@link #setLine(float, int) line}.
      *
@@ -575,6 +629,16 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the cue box anchor positioned by {@link #setLine(float, int) line}.
+     *
+     * @see Cue#lineAnchor
+     */
+    @AnchorType
+    public int getLineAnchor() {
+      return lineAnchor;
+    }
+
     /**
      * Sets the fractional position of the {@link #setPositionAnchor(int) positionAnchor} of the cue
      * box within the viewport in the direction orthogonal to {@link #setLine(float, int) line}.
@@ -590,6 +654,16 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the fractional position of the {@link #setPositionAnchor(int) positionAnchor} of the cue
+     * box within the viewport in the direction orthogonal to {@link #setLine(float, int) line}.
+     *
+     * @see Cue#position
+     */
+    public float getPosition() {
+      return position;
+    }
+
     /**
      * Sets the cue box anchor positioned by {@link #setPosition(float) position}.
      *
@@ -605,7 +679,17 @@ public final class Cue {
     }
 
     /**
-     * Sets the default text size type for this cue's text.
+     * Gets the cue box anchor positioned by {@link #setPosition(float) position}.
+     *
+     * @see Cue#positionAnchor
+     */
+    @AnchorType
+    public int getPositionAnchor() {
+      return positionAnchor;
+    }
+
+    /**
+     * Sets the default text size and type for this cue's text.
      *
      * @see Cue#textSize
      * @see Cue#textSizeType
@@ -616,12 +700,29 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the default text size type for this cue's text.
+     *
+     * @see Cue#textSizeType
+     */
+    @TextSizeType
+    public int getTextSizeType() {
+      return textSizeType;
+    }
+
+    /**
+     * Gets the default text size for this cue's text.
+     *
+     * @see Cue#textSize
+     */
+    public float getTextSize() {
+      return textSize;
+    }
+
     /**
      * Sets the size of the cue box in the writing direction specified as a fraction of the viewport
      * size in that direction.
      *
-     * @see Cue#textSize
-     * @see Cue#textSizeType
      * @see Cue#size
      */
     public Builder setSize(float size) {
@@ -630,7 +731,17 @@ public final class Cue {
     }
 
     /**
-     * Sets the bitmap height as a fraction of the of the viewport size.
+     * Gets the size of the cue box in the writing direction specified as a fraction of the viewport
+     * size in that direction.
+     *
+     * @see Cue#size
+     */
+    public float getSize() {
+      return size;
+    }
+
+    /**
+     * Sets the bitmap height as a fraction of the viewport size.
      *
      * @see Cue#bitmapHeight
      */
@@ -639,6 +750,15 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the bitmap height as a fraction of the viewport size.
+     *
+     * @see Cue#bitmapHeight
+     */
+    public float getBitmapHeight() {
+      return bitmapHeight;
+    }
+
     /**
      * Sets the fill color of the window.
      *
@@ -653,6 +773,25 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Returns true if the fill color of the window is set.
+     *
+     * @see Cue#windowColorSet
+     */
+    public boolean isWindowColorSet() {
+      return windowColorSet;
+    }
+
+    /**
+     * Gets the fill color of the window.
+     *
+     * @see Cue#windowColor
+     */
+    @ColorInt
+    public int getWindowColor() {
+      return windowColor;
+    }
+
     /**
      * Sets the vertical formatting for this Cue.
      *
@@ -663,6 +802,16 @@ public final class Cue {
       return this;
     }
 
+    /**
+     * Gets the vertical formatting for this Cue.
+     *
+     * @see Cue#verticalType
+     */
+    @VerticalType
+    public int getVerticalType() {
+      return verticalType;
+    }
+
     /** Build the cue. */
     public Cue build() {
       return new Cue(

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlDecoder.java

@@ -540,6 +540,21 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
               break;
           }
           break;
+        case TtmlNode.ATTR_TTS_WRITING_MODE:
+          switch (Util.toLowerInvariant(attributeValue)) {
+              // TODO: Support horizontal RTL modes.
+            case TtmlNode.VERTICAL:
+            case TtmlNode.VERTICAL_LR:
+              style = createIfNull(style).setVerticalType(Cue.VERTICAL_TYPE_LR);
+              break;
+            case TtmlNode.VERTICAL_RL:
+              style = createIfNull(style).setVerticalType(Cue.VERTICAL_TYPE_RL);
+              break;
+            default:
+              // ignore
+              break;
+          }
+          break;
         default:
           // ignore
           break;

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlNode.java

@@ -28,7 +28,6 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.TreeMap;
 import java.util.TreeSet;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@@ -67,7 +66,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   public static final String ATTR_TTS_COLOR = "color";
   public static final String ATTR_TTS_TEXT_DECORATION = "textDecoration";
   public static final String ATTR_TTS_TEXT_ALIGN = "textAlign";
+  public static final String ATTR_TTS_WRITING_MODE = "writingMode";
 
+  // Values for textDecoration
   public static final String LINETHROUGH = "linethrough";
   public static final String NO_LINETHROUGH = "nolinethrough";
   public static final String UNDERLINE = "underline";
@@ -75,12 +76,18 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   public static final String ITALIC = "italic";
   public static final String BOLD = "bold";
 
+  // Values for textAlign
   public static final String LEFT = "left";
   public static final String CENTER = "center";
   public static final String RIGHT = "right";
   public static final String START = "start";
   public static final String END = "end";
 
+  // Values for writingMode
+  public static final String VERTICAL = "tb";
+  public static final String VERTICAL_LR = "tblr";
+  public static final String VERTICAL_RL = "tbrl";
+
   @Nullable public final String tag;
   @Nullable public final String text;
   public final boolean isTextNode;
@@ -211,7 +218,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     List<Pair<String, String>> regionImageOutputs = new ArrayList<>();
     traverseForImage(timeUs, regionId, regionImageOutputs);
 
-    TreeMap<String, SpannableStringBuilder> regionTextOutputs = new TreeMap<>();
+    TreeMap<String, Cue.Builder> regionTextOutputs = new TreeMap<>();
     traverseForText(timeUs, false, regionId, regionTextOutputs);
     traverseForStyle(timeUs, globalStyles, regionTextOutputs);
 
@@ -242,20 +249,16 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
 
     // Create text based cues.
-    for (Entry<String, SpannableStringBuilder> entry : regionTextOutputs.entrySet()) {
+    for (Map.Entry<String, Cue.Builder> entry : regionTextOutputs.entrySet()) {
       TtmlRegion region = Assertions.checkNotNull(regionMap.get(entry.getKey()));
-      cues.add(
+      Cue.Builder regionOutput = entry.getValue();
-          new Cue(
+      cleanUpText((SpannableStringBuilder) Assertions.checkNotNull(regionOutput.getText()));
-              cleanUpText(entry.getValue()),
+      regionOutput.setLine(region.line, region.lineType);
-              /* textAlignment= */ null,
+      regionOutput.setLineAnchor(region.lineAnchor);
-              region.line,
+      regionOutput.setPosition(region.position);
-              region.lineType,
+      regionOutput.setSize(region.width);
-              region.lineAnchor,
+      regionOutput.setTextSize(region.textSize, region.textSizeType);
-              region.position,
+      cues.add(regionOutput.build());
-              /* positionAnchor= */ Cue.TYPE_UNSET,
-              region.width,
-              region.textSizeType,
-              region.textSize));
     }
 
     return cues;
@@ -277,7 +280,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       long timeUs,
       boolean descendsPNode,
       String inheritedRegion,
-      Map<String, SpannableStringBuilder> regionOutputs) {
+      Map<String, Cue.Builder> regionOutputs) {
     nodeStartsByRegion.clear();
     nodeEndsByRegion.clear();
     if (TAG_METADATA.equals(tag)) {
@@ -288,13 +291,14 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     String resolvedRegionId = ANONYMOUS_REGION_ID.equals(regionId) ? inheritedRegion : regionId;
 
     if (isTextNode && descendsPNode) {
-      getRegionOutput(resolvedRegionId, regionOutputs).append(Assertions.checkNotNull(text));
+      getRegionOutputText(resolvedRegionId, regionOutputs).append(Assertions.checkNotNull(text));
     } else if (TAG_BR.equals(tag) && descendsPNode) {
-      getRegionOutput(resolvedRegionId, regionOutputs).append('\n');
+      getRegionOutputText(resolvedRegionId, regionOutputs).append('\n');
     } else if (isActive(timeUs)) {
       // This is a container node, which can contain zero or more children.
-      for (Entry<String, SpannableStringBuilder> entry : regionOutputs.entrySet()) {
+      for (Map.Entry<String, Cue.Builder> entry : regionOutputs.entrySet()) {
-        nodeStartsByRegion.put(entry.getKey(), entry.getValue().length());
+        nodeStartsByRegion.put(
+            entry.getKey(), Assertions.checkNotNull(entry.getValue().getText()).length());
       }
 
       boolean isPNode = TAG_P.equals(tag);
@@ -303,36 +307,38 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             regionOutputs);
       }
       if (isPNode) {
-        TtmlRenderUtil.endParagraph(getRegionOutput(resolvedRegionId, regionOutputs));
+        TtmlRenderUtil.endParagraph(getRegionOutputText(resolvedRegionId, regionOutputs));
       }
 
-      for (Entry<String, SpannableStringBuilder> entry : regionOutputs.entrySet()) {
+      for (Map.Entry<String, Cue.Builder> entry : regionOutputs.entrySet()) {
-        nodeEndsByRegion.put(entry.getKey(), entry.getValue().length());
+        nodeEndsByRegion.put(
+            entry.getKey(), Assertions.checkNotNull(entry.getValue().getText()).length());
       }
     }
   }
 
-  private static SpannableStringBuilder getRegionOutput(
+  private static SpannableStringBuilder getRegionOutputText(
-      String resolvedRegionId, Map<String, SpannableStringBuilder> regionOutputs) {
+      String resolvedRegionId, Map<String, Cue.Builder> regionOutputs) {
     if (!regionOutputs.containsKey(resolvedRegionId)) {
-      regionOutputs.put(resolvedRegionId, new SpannableStringBuilder());
+      Cue.Builder regionOutput = new Cue.Builder();
+      regionOutput.setText(new SpannableStringBuilder());
+      regionOutputs.put(resolvedRegionId, regionOutput);
     }
-    return regionOutputs.get(resolvedRegionId);
+    return (SpannableStringBuilder)
+        Assertions.checkNotNull(regionOutputs.get(resolvedRegionId).getText());
   }
 
   private void traverseForStyle(
-      long timeUs,
+      long timeUs, Map<String, TtmlStyle> globalStyles, Map<String, Cue.Builder> regionOutputs) {
-      Map<String, TtmlStyle> globalStyles,
-      Map<String, SpannableStringBuilder> regionOutputs) {
     if (!isActive(timeUs)) {
       return;
     }
-    for (Entry<String, Integer> entry : nodeEndsByRegion.entrySet()) {
+    for (Map.Entry<String, Integer> entry : nodeEndsByRegion.entrySet()) {
       String regionId = entry.getKey();
       int start = nodeStartsByRegion.containsKey(regionId) ? nodeStartsByRegion.get(regionId) : 0;
       int end = entry.getValue();
       if (start != end) {
-        SpannableStringBuilder regionOutput = Assertions.checkNotNull(regionOutputs.get(regionId));
+        Cue.Builder regionOutput = Assertions.checkNotNull(regionOutputs.get(regionId));
         applyStyleToOutput(globalStyles, regionOutput, start, end);
       }
     }
@@ -342,17 +348,20 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   }
 
   private void applyStyleToOutput(
-      Map<String, TtmlStyle> globalStyles,
+      Map<String, TtmlStyle> globalStyles, Cue.Builder regionOutput, int start, int end) {
-      SpannableStringBuilder regionOutput,
-      int start,
-      int end) {
     @Nullable TtmlStyle resolvedStyle = TtmlRenderUtil.resolveStyle(style, styleIds, globalStyles);
+    @Nullable SpannableStringBuilder text = (SpannableStringBuilder) regionOutput.getText();
+    if (text == null) {
+      text = new SpannableStringBuilder();
+      regionOutput.setText(text);
+    }
     if (resolvedStyle != null) {
-      TtmlRenderUtil.applyStylesToSpan(regionOutput, start, end, resolvedStyle);
+      TtmlRenderUtil.applyStylesToSpan(text, start, end, resolvedStyle);
+      regionOutput.setVerticalType(resolvedStyle.getVerticalType());
     }
   }
 
-  private SpannableStringBuilder cleanUpText(SpannableStringBuilder builder) {
+  private static void cleanUpText(SpannableStringBuilder builder) {
     // Having joined the text elements, we need to do some final cleanup on the result.
     // 1. Collapse multiple consecutive spaces into a single space.
     int builderLength = builder.length();
@@ -396,7 +405,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       builder.delete(builderLength - 1, builderLength);
       /*builderLength--;*/
     }
-    return builder;
   }
 
 }

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlStyle.java

@@ -19,6 +19,8 @@ import android.graphics.Typeface;
 import android.text.Layout;
 import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.text.Cue;
+import com.google.android.exoplayer2.text.Cue.VerticalType;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -73,6 +75,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private float fontSize;
   private @MonotonicNonNull String id;
   private Layout.@MonotonicNonNull Alignment textAlign;
+  @Cue.VerticalType private int verticalType;
 
   public TtmlStyle() {
     linethrough = UNSPECIFIED;
@@ -80,6 +83,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     bold = UNSPECIFIED;
     italic = UNSPECIFIED;
     fontSizeUnit = UNSPECIFIED;
+    verticalType = Cue.TYPE_UNSET;
   }
 
   /**
@@ -220,6 +224,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       if (chaining && !hasBackgroundColor && ancestor.hasBackgroundColor) {
         setBackgroundColor(ancestor.backgroundColor);
       }
+      if (chaining && verticalType != Cue.TYPE_UNSET && ancestor.verticalType == Cue.TYPE_UNSET) {
+        setVerticalType(ancestor.verticalType);
+      }
     }
     return this;
   }
@@ -262,4 +269,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     return fontSize;
   }
 
+  public TtmlStyle setVerticalType(@VerticalType int verticalType) {
+    this.verticalType = verticalType;
+    return this;
+  }
+
+  @VerticalType
+  public int getVerticalType() {
+    return verticalType;
+  }
 }

library/core/src/test/assets/ttml/vertical_text.xml

@@ -0,0 +1,17 @@
+<tt xmlns:ttm="http://www.w3.org/2006/10/ttaf1#metadata"
+    xmlns:ttp="http://www.w3.org/2006/10/ttaf1#parameter"
+    xmlns:tts="http://www.w3.org/2006/10/ttaf1#style"
+    xmlns="http://www.w3.org/ns/ttml"
+    xmlns="http://www.w3.org/2006/10/ttaf1">
+  <body>
+    <div>
+      <p begin="10s" end="18s" tts:writingMode="tbrl">Vertical right-to-left (e.g. Japanese)</p>
+    </div>
+    <div>
+      <p begin="20s" end="28s" tts:writingMode="tblr">Vertical left-to-right (e.g. Mongolian)</p>
+    </div>
+    <div>
+      <p begin="30s" end="38s">Horizontal text</p>
+    </div>
+  </body>
+</tt>

library/core/src/test/java/com/google/android/exoplayer2/text/ttml/TtmlDecoderTest.java

@@ -66,6 +66,7 @@ public final class TtmlDecoderTest {
   private static final String BITMAP_REGION_FILE = "ttml/bitmap_percentage_region.xml";
   private static final String BITMAP_PIXEL_REGION_FILE = "ttml/bitmap_pixel_region.xml";
   private static final String BITMAP_UNSUPPORTED_REGION_FILE = "ttml/bitmap_unsupported_region.xml";
+  private static final String VERTICAL_TEXT_FILE = "ttml/vertical_text.xml";
 
   @Test
   public void testInlineAttributes() throws IOException, SubtitleDecoderException {
@@ -587,6 +588,26 @@ public final class TtmlDecoderTest {
     assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
   }
 
+  @Test
+  public void testVerticalText() throws IOException, SubtitleDecoderException {
+    TtmlSubtitle subtitle = getSubtitle(VERTICAL_TEXT_FILE);
+
+    List<Cue> firstCues = subtitle.getCues(10_000_000);
+    assertThat(firstCues).hasSize(1);
+    Cue firstCue = firstCues.get(0);
+    assertThat(firstCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_RL);
+
+    List<Cue> secondCues = subtitle.getCues(20_000_000);
+    assertThat(secondCues).hasSize(1);
+    Cue secondCue = secondCues.get(0);
+    assertThat(secondCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_LR);
+
+    List<Cue> thirdCues = subtitle.getCues(30_000_000);
+    assertThat(thirdCues).hasSize(1);
+    Cue thirdCue = thirdCues.get(0);
+    assertThat(thirdCue.verticalType).isEqualTo(Cue.TYPE_UNSET);
+  }
+
   private void assertSpans(
       TtmlSubtitle subtitle,
       int second,