Support TTML font size using % correctly.

For TTML, if the font size is expressed in %, the font size should be relative
to the cellResolution of the document which we did not support before. This CL
adds support for handling this correctly.
Note that this still does not support font size using c unit.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=196985694

RELEASENOTES.md

@@ -25,6 +25,8 @@
       time that can make text size of each region much smaller than defined.
     * Fix an issue when the caption line has no text (empty line or only line
       break), and the line's background is still displayed.
+    * Support TTML font size using % correctly (as percentage of document cell
+      resolution).
 
 ### 2.8.0 ###
 
@@ -101,7 +103,7 @@
   * Allow multiple listeners for `DefaultDrmSessionManager`.
   * Pass `DrmSessionManager` to `ExoPlayerFactory` instead of `RendererFactory`.
   * Change minimum API requirement for CBC and pattern encryption from 24 to 25
-    ([#4022][https://github.com/google/ExoPlayer/issues/4022]).
+    ([#4022](https://github.com/google/ExoPlayer/issues/4022)).
   * Fix handling of 307/308 redirects when making license requests
     ([#4108](https://github.com/google/ExoPlayer/issues/4108)).
 * HLS:

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

@@ -38,6 +38,7 @@ import org.xmlpull.v1.XmlPullParserFactory;
 /**
  * A {@link SimpleSubtitleDecoder} for TTML supporting the DFXP presentation profile. Features
  * supported by this decoder are:
+ *
  * <ul>
  *   <li>content
  *   <li>core
@@ -51,7 +52,9 @@ import org.xmlpull.v1.XmlPullParserFactory;
  *   <li>time-clock
  *   <li>time-offset-with-frames
  *   <li>time-offset-with-ticks
+ *   <li>cell-resolution
  * </ul>
+ *
  * @see <a href="http://www.w3.org/TR/ttaf1-dfxp/">TTML specification</a>
  */
 public final class TtmlDecoder extends SimpleSubtitleDecoder {
@@ -74,11 +77,14 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
   private static final Pattern FONT_SIZE = Pattern.compile("^(([0-9]*.)?[0-9]+)(px|em|%)$");
   private static final Pattern PERCENTAGE_COORDINATES =
       Pattern.compile("^(\\d+\\.?\\d*?)% (\\d+\\.?\\d*?)%$");
+  private static final Pattern CELL_RESOLUTION = Pattern.compile("^(\\d+) (\\d+)$");
 
   private static final int DEFAULT_FRAME_RATE = 30;
 
   private static final FrameAndTickRate DEFAULT_FRAME_AND_TICK_RATE =
       new FrameAndTickRate(DEFAULT_FRAME_RATE, 1, 1);
+  private static final CellResolution DEFAULT_CELL_RESOLUTION =
+      new CellResolution(/* columns= */ 32, /* rows= */ 15);
 
   private final XmlPullParserFactory xmlParserFactory;
 
@@ -107,6 +113,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       int unsupportedNodeDepth = 0;
       int eventType = xmlParser.getEventType();
       FrameAndTickRate frameAndTickRate = DEFAULT_FRAME_AND_TICK_RATE;
+      CellResolution cellResolution = DEFAULT_CELL_RESOLUTION;
       while (eventType != XmlPullParser.END_DOCUMENT) {
         TtmlNode parent = nodeStack.peekLast();
         if (unsupportedNodeDepth == 0) {
@@ -114,12 +121,13 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
           if (eventType == XmlPullParser.START_TAG) {
             if (TtmlNode.TAG_TT.equals(name)) {
               frameAndTickRate = parseFrameAndTickRates(xmlParser);
+              cellResolution = parseCellResolution(xmlParser, DEFAULT_CELL_RESOLUTION);
             }
             if (!isSupportedTag(name)) {
               Log.i(TAG, "Ignoring unsupported tag: " + xmlParser.getName());
               unsupportedNodeDepth++;
             } else if (TtmlNode.TAG_HEAD.equals(name)) {
-              parseHeader(xmlParser, globalStyles, regionMap);
+              parseHeader(xmlParser, globalStyles, regionMap, cellResolution);
             } else {
               try {
                 TtmlNode node = parseNode(xmlParser, parent, regionMap, frameAndTickRate);
@@ -193,8 +201,36 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
     return new FrameAndTickRate(frameRate * frameRateMultiplier, subFrameRate, tickRate);
   }
 
-  private Map<String, TtmlStyle> parseHeader(XmlPullParser xmlParser,
-      Map<String, TtmlStyle> globalStyles, Map<String, TtmlRegion> globalRegions)
+  private CellResolution parseCellResolution(XmlPullParser xmlParser, CellResolution defaultValue)
+      throws SubtitleDecoderException {
+    String cellResolution = xmlParser.getAttributeValue(TTP, "cellResolution");
+    if (cellResolution == null) {
+      return defaultValue;
+    }
+
+    Matcher cellResolutionMatcher = CELL_RESOLUTION.matcher(cellResolution);
+    if (!cellResolutionMatcher.matches()) {
+      Log.w(TAG, "Ignoring malformed cell resolution: " + cellResolution);
+      return defaultValue;
+    }
+    try {
+      int columns = Integer.parseInt(cellResolutionMatcher.group(1));
+      int rows = Integer.parseInt(cellResolutionMatcher.group(2));
+      if (columns == 0 || rows == 0) {
+        throw new SubtitleDecoderException("Invalid cell resolution " + columns + " " + rows);
+      }
+      return new CellResolution(columns, rows);
+    } catch (NumberFormatException e) {
+      Log.w(TAG, "Ignoring malformed cell resolution: " + cellResolution);
+      return defaultValue;
+    }
+  }
+
+  private Map<String, TtmlStyle> parseHeader(
+      XmlPullParser xmlParser,
+      Map<String, TtmlStyle> globalStyles,
+      Map<String, TtmlRegion> globalRegions,
+      CellResolution cellResolution)
       throws IOException, XmlPullParserException {
     do {
       xmlParser.next();
@@ -210,7 +246,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
           globalStyles.put(style.getId(), style);
         }
       } else if (XmlPullParserUtil.isStartTag(xmlParser, TtmlNode.TAG_REGION)) {
-        TtmlRegion ttmlRegion = parseRegionAttributes(xmlParser);
+        TtmlRegion ttmlRegion = parseRegionAttributes(xmlParser, cellResolution);
         if (ttmlRegion != null) {
           globalRegions.put(ttmlRegion.id, ttmlRegion);
         }
@@ -221,12 +257,12 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
 
   /**
    * Parses a region declaration.
-   * <p>
-   * If the region defines an origin and extent, it is required that they're defined as percentages
-   * of the viewport. Region declarations that define origin and extent in other formats are
-   * unsupported, and null is returned.
+   *
+   * <p>If the region defines an origin and extent, it is required that they're defined as
+   * percentages of the viewport. Region declarations that define origin and extent in other formats
+   * are unsupported, and null is returned.
    */
-  private TtmlRegion parseRegionAttributes(XmlPullParser xmlParser) {
+  private TtmlRegion parseRegionAttributes(XmlPullParser xmlParser, CellResolution cellResolution) {
     String regionId = XmlPullParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_ID);
     if (regionId == null) {
       return null;
@@ -305,7 +341,16 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       }
     }
 
-    return new TtmlRegion(regionId, position, line, Cue.LINE_TYPE_FRACTION, lineAnchor, width);
+    float regionTextHeight = 1.0f / cellResolution.rows;
+    return new TtmlRegion(
+        regionId,
+        position,
+        line,
+        /* lineType= */ Cue.LINE_TYPE_FRACTION,
+        lineAnchor,
+        width,
+        /* textSizeType= */ Cue.TEXT_SIZE_TYPE_FRACTIONAL_IGNORE_PADDING,
+        /* textSize= */ regionTextHeight);
   }
 
   private String[] parseStyleIds(String parentStyleIds) {
@@ -594,4 +639,15 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       this.tickRate = tickRate;
     }
   }
+
+  /** Represents the cell resolution for a TTML file. */
+  private static final class CellResolution {
+    final int columns;
+    final int rows;
+
+    CellResolution(int columns, int rows) {
+      this.columns = columns;
+      this.rows = rows;
+    }
+  }
 }

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

@@ -179,8 +179,18 @@ import java.util.TreeSet;
     List<Cue> cues = new ArrayList<>();
     for (Entry<String, SpannableStringBuilder> entry : regionOutputs.entrySet()) {
       TtmlRegion region = regionMap.get(entry.getKey());
-      cues.add(new Cue(cleanUpText(entry.getValue()), null, region.line, region.lineType,
-          region.lineAnchor, region.position, Cue.TYPE_UNSET, region.width));
+      cues.add(
+          new Cue(
+              cleanUpText(entry.getValue()),
+              /* textAlignment= */ null,
+              region.line,
+              region.lineType,
+              region.lineAnchor,
+              region.position,
+              /* positionAnchor= */ Cue.TYPE_UNSET,
+              region.width,
+              region.textSizeType,
+              region.textSize));
     }
     return cues;
   }

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

@@ -25,22 +25,41 @@ import com.google.android.exoplayer2.text.Cue;
   public final String id;
   public final float position;
   public final float line;
-  @Cue.LineType public final int lineType;
-  @Cue.AnchorType public final int lineAnchor;
+  public final @Cue.LineType int lineType;
+  public final @Cue.AnchorType int lineAnchor;
   public final float width;
+  public final @Cue.TextSizeType int textSizeType;
+  public final float textSize;
 
   public TtmlRegion(String id) {
-    this(id, Cue.DIMEN_UNSET, Cue.DIMEN_UNSET, Cue.TYPE_UNSET, Cue.TYPE_UNSET, Cue.DIMEN_UNSET);
+    this(
+        id,
+        /* position= */ Cue.DIMEN_UNSET,
+        /* line= */ Cue.DIMEN_UNSET,
+        /* lineType= */ Cue.TYPE_UNSET,
+        /* lineAnchor= */ Cue.TYPE_UNSET,
+        /* width= */ Cue.DIMEN_UNSET,
+        /* textSizeType= */ Cue.TYPE_UNSET,
+        /* textSize= */ Cue.DIMEN_UNSET);
   }
 
-  public TtmlRegion(String id, float position, float line, @Cue.LineType int lineType,
-      @Cue.AnchorType int lineAnchor, float width) {
+  public TtmlRegion(
+      String id,
+      float position,
+      float line,
+      @Cue.LineType int lineType,
+      @Cue.AnchorType int lineAnchor,
+      float width,
+      int textSizeType,
+      float textSize) {
     this.id = id;
     this.position = position;
     this.line = line;
     this.lineType = lineType;
     this.lineAnchor = lineAnchor;
     this.width = width;
+    this.textSizeType = textSizeType;
+    this.textSize = textSize;
   }
 
 }

library/ui/src/main/java/com/google/android/exoplayer2/ui/SubtitleView.java

@@ -51,14 +51,10 @@ public final class SubtitleView extends View implements TextOutput {
    */
   public static final float DEFAULT_BOTTOM_PADDING_FRACTION = 0.08f;
 
-  private static final int FRACTIONAL = 0;
-  private static final int FRACTIONAL_IGNORE_PADDING = 1;
-  private static final int ABSOLUTE = 2;
-
   private final List<SubtitlePainter> painters;
 
   private List<Cue> cues;
-  private int textSizeType;
+  private @Cue.TextSizeType int textSizeType;
   private float textSize;
   private boolean applyEmbeddedStyles;
   private boolean applyEmbeddedFontSizes;
@@ -72,7 +68,7 @@ public final class SubtitleView extends View implements TextOutput {
   public SubtitleView(Context context, AttributeSet attrs) {
     super(context, attrs);
     painters = new ArrayList<>();
-    textSizeType = FRACTIONAL;
+    textSizeType = Cue.TEXT_SIZE_TYPE_FRACTIONAL;
     textSize = DEFAULT_TEXT_SIZE_FRACTION;
     applyEmbeddedStyles = true;
     applyEmbeddedFontSizes = true;
@@ -120,7 +116,9 @@ public final class SubtitleView extends View implements TextOutput {
     } else {
       resources = context.getResources();
     }
-    setTextSize(ABSOLUTE, TypedValue.applyDimension(unit, size, resources.getDisplayMetrics()));
+    setTextSize(
+        Cue.TEXT_SIZE_TYPE_ABSOLUTE,
+        TypedValue.applyDimension(unit, size, resources.getDisplayMetrics()));
   }
 
   /**
@@ -154,10 +152,14 @@ public final class SubtitleView extends View implements TextOutput {
    *     height after the top and bottom padding has been subtracted.
    */
   public void setFractionalTextSize(float fractionOfHeight, boolean ignorePadding) {
-    setTextSize(ignorePadding ? FRACTIONAL_IGNORE_PADDING : FRACTIONAL, fractionOfHeight);
+    setTextSize(
+        ignorePadding
+            ? Cue.TEXT_SIZE_TYPE_FRACTIONAL_IGNORE_PADDING
+            : Cue.TEXT_SIZE_TYPE_FRACTIONAL,
+        fractionOfHeight);
   }
 
-  private void setTextSize(int textSizeType, float textSize) {
+  private void setTextSize(@Cue.TextSizeType int textSizeType, float textSize) {
     if (this.textSizeType == textSizeType && this.textSize == textSize) {
       return;
     }
@@ -255,17 +257,61 @@ public final class SubtitleView extends View implements TextOutput {
       // No space to draw subtitles.
       return;
     }
+    int rawViewHeight = rawBottom - rawTop;
+    int viewHeightMinusPadding = bottom - top;
 
-    float textSizePx = textSizeType == ABSOLUTE ? textSize
-        : textSize * (textSizeType == FRACTIONAL ? (bottom - top) : (rawBottom - rawTop));
-    if (textSizePx <= 0) {
+    float defaultViewTextSizePx =
+        resolveTextSize(textSizeType, textSize, rawViewHeight, viewHeightMinusPadding);
+    if (defaultViewTextSizePx <= 0) {
       // Text has no height.
       return;
     }
 
     for (int i = 0; i < cueCount; i++) {
-      painters.get(i).draw(cues.get(i), applyEmbeddedStyles, applyEmbeddedFontSizes, style,
-          textSizePx, bottomPaddingFraction, canvas, left, top, right, bottom);
+      Cue cue = cues.get(i);
+      float textSizePx =
+          resolveTextSizeForCue(cue, rawViewHeight, viewHeightMinusPadding, defaultViewTextSizePx);
+      SubtitlePainter painter = painters.get(i);
+      painter.draw(
+          cue,
+          applyEmbeddedStyles,
+          applyEmbeddedFontSizes,
+          style,
+          textSizePx,
+          bottomPaddingFraction,
+          canvas,
+          left,
+          top,
+          right,
+          bottom);
+    }
+  }
+
+  private float resolveTextSizeForCue(
+      Cue cue, int rawViewHeight, int viewHeightMinusPadding, float defaultViewTextSizePx) {
+    if (cue.textSizeType == Cue.TYPE_UNSET || cue.textSize == Cue.DIMEN_UNSET) {
+      return defaultViewTextSizePx;
+    }
+    float defaultCueTextSizePx =
+        resolveTextSize(cue.textSizeType, cue.textSize, rawViewHeight, viewHeightMinusPadding);
+    return defaultCueTextSizePx > 0 ? defaultCueTextSizePx : defaultViewTextSizePx;
+  }
+
+  private float resolveTextSize(
+      @Cue.TextSizeType int textSizeType,
+      float textSize,
+      int rawViewHeight,
+      int viewHeightMinusPadding) {
+    switch (textSizeType) {
+      case Cue.TEXT_SIZE_TYPE_ABSOLUTE:
+        return textSize;
+      case Cue.TEXT_SIZE_TYPE_FRACTIONAL:
+        return textSize * viewHeightMinusPadding;
+      case Cue.TEXT_SIZE_TYPE_FRACTIONAL_IGNORE_PADDING:
+        return textSize * rawViewHeight;
+      case Cue.TYPE_UNSET:
+      default:
+        return Cue.DIMEN_UNSET;
     }
   }