Merge pull request #4178 from danybony:subtitle_color_in_cue_class

PiperOrigin-RevId: 295548715

RELEASENOTES.md

@@ -41,6 +41,11 @@
     (rendering is coming later).
   * Fix `SubtitlePainter` to render `EDGE_TYPE_OUTLINE` using the correct color
     ([#6724](https://github.com/google/ExoPlayer/pull/6724)).
+  * Add support for WebVTT default
+    [text](https://www.w3.org/TR/webvtt1/#default-text-color) and
+    [background](https://www.w3.org/TR/webvtt1/#default-text-background) colors
+    ([PR #4178](https://github.com/google/ExoPlayer/pull/4178),
+    [issue #6581](https://github.com/google/ExoPlayer/issues/6581)).
 * DRM: Add support for attaching DRM sessions to clear content in the demo app.
 * Downloads: Merge downloads in `SegmentDownloader` to improve overall download
   speed ([#5978](https://github.com/google/ExoPlayer/issues/5978)).

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

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.text.webvtt;
 import static com.google.android.exoplayer2.text.SpanUtil.addOrReplaceSpan;
 import static java.lang.annotation.RetentionPolicy.SOURCE;
 
+import android.graphics.Color;
 import android.graphics.Typeface;
 import android.text.Layout;
 import android.text.SpannableStringBuilder;
@@ -48,7 +49,9 @@ import java.lang.annotation.Retention;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@@ -138,6 +141,44 @@ public final class WebvttCueParser {
   private static final String TAG = "WebvttCueParser";
 
   /**
+   * See WebVTT's <a href="https://www.w3.org/TR/webvtt1/#default-text-color">default text
+   * colors</a>.
+   */
+  private static final Map<String, Integer> DEFAULT_TEXT_COLORS;
+
+  static {
+    Map<String, Integer> defaultColors = new HashMap<>();
+    defaultColors.put("white", Color.rgb(255, 255, 255));
+    defaultColors.put("lime", Color.rgb(0, 255, 0));
+    defaultColors.put("cyan", Color.rgb(0, 255, 255));
+    defaultColors.put("red", Color.rgb(255, 0, 0));
+    defaultColors.put("yellow", Color.rgb(255, 255, 0));
+    defaultColors.put("magenta", Color.rgb(255, 0, 255));
+    defaultColors.put("blue", Color.rgb(0, 0, 255));
+    defaultColors.put("black", Color.rgb(0, 0, 0));
+    DEFAULT_TEXT_COLORS = Collections.unmodifiableMap(defaultColors);
+  }
+
+  /**
+   * See WebVTT's <a href="https://www.w3.org/TR/webvtt1/#default-text-background">default text
+   * background colors</a>.
+   */
+  private static final Map<String, Integer> DEFAULT_BACKGROUND_COLORS;
+
+  static {
+    Map<String, Integer> defaultBackgroundColors = new HashMap<>();
+    defaultBackgroundColors.put("bg_white", Color.rgb(255, 255, 255));
+    defaultBackgroundColors.put("bg_lime", Color.rgb(0, 255, 0));
+    defaultBackgroundColors.put("bg_cyan", Color.rgb(0, 255, 255));
+    defaultBackgroundColors.put("bg_red", Color.rgb(255, 0, 0));
+    defaultBackgroundColors.put("bg_yellow", Color.rgb(255, 255, 0));
+    defaultBackgroundColors.put("bg_magenta", Color.rgb(255, 0, 255));
+    defaultBackgroundColors.put("bg_blue", Color.rgb(0, 0, 255));
+    defaultBackgroundColors.put("bg_black", Color.rgb(0, 0, 0));
+    DEFAULT_BACKGROUND_COLORS = Collections.unmodifiableMap(defaultBackgroundColors);
+  }
+
+  /**
    * Parses the next valid WebVTT cue in a parsable array, including timestamps, settings and text.
    *
    * @param webvttData Parsable WebVTT file data.
@@ -514,6 +555,8 @@ public final class WebvttCueParser {
         text.setSpan(new UnderlineSpan(), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
         break;
       case TAG_CLASS:
+        applyDefaultColors(text, startTag.classes, start, end);
+        break;
       case TAG_LANG:
       case TAG_VOICE:
       case "": // Case of the "whole cue" virtual tag.
@@ -529,6 +572,26 @@ public final class WebvttCueParser {
     }
   }
 
+  /**
+   * Adds {@link ForegroundColorSpan}s and {@link BackgroundColorSpan}s to {@code text} for entries
+   * in {@code classes} that match WebVTT's <a
+   * href="https://www.w3.org/TR/webvtt1/#default-text-color">default text colors</a> or <a
+   * href="https://www.w3.org/TR/webvtt1/#default-text-background">default text background
+   * colors</a>.
+   */
+  private static void applyDefaultColors(
+      SpannableStringBuilder text, String[] classes, int start, int end) {
+    for (String className : classes) {
+      if (DEFAULT_TEXT_COLORS.containsKey(className)) {
+        int color = DEFAULT_TEXT_COLORS.get(className);
+        text.setSpan(new ForegroundColorSpan(color), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+      } else if (DEFAULT_BACKGROUND_COLORS.containsKey(className)) {
+        int color = DEFAULT_BACKGROUND_COLORS.get(className);
+        text.setSpan(new BackgroundColorSpan(color), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+      }
+    }
+  }
+
   private static void applyStyleToText(SpannableStringBuilder spannedText, WebvttCssStyle style,
       int start, int end) {
     if (style == null) {

library/core/src/test/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParserTest.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.text.webvtt;
 import static com.google.android.exoplayer2.testutil.truth.SpannedSubject.assertThat;
 import static com.google.common.truth.Truth.assertThat;
 
+import android.graphics.Color;
 import android.text.Spanned;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.text.span.RubySpan;
@@ -80,6 +81,47 @@ public final class WebvttCueParserTest {
   }
 
   @Test
+  public void testParseDefaultTextColor() throws Exception {
+    Spanned text = parseCueText("In this sentence <c.red>this text</c> is red");
+
+    assertThat(text.toString()).isEqualTo("In this sentence this text is red");
+    assertThat(text)
+        .hasForegroundColorSpanBetween(
+            "In this sentence ".length(), "In this sentence this text".length())
+        .withColor(Color.RED);
+  }
+
+  @Test
+  public void testParseUnsupportedDefaultTextColor() throws Exception {
+    Spanned text = parseCueText("In this sentence <c.papayawhip>this text</c> is not papaya");
+
+    assertThat(text.toString()).isEqualTo("In this sentence this text is not papaya");
+    assertThat(text).hasNoSpans();
+  }
+
+  @Test
+  public void testParseDefaultBackgroundColor() throws Exception {
+    Spanned text = parseCueText("In this sentence <c.bg_cyan>this text</c> has a cyan background");
+
+    assertThat(text.toString()).isEqualTo("In this sentence this text has a cyan background");
+    assertThat(text)
+        .hasBackgroundColorSpanBetween(
+            "In this sentence ".length(), "In this sentence this text".length())
+        .withColor(Color.CYAN);
+  }
+
+  @Test
+  public void testParseUnsupportedDefaultBackgroundColor() throws Exception {
+    Spanned text =
+        parseCueText(
+            "In this sentence <c.bg_papayawhip>this text</c> doesn't have a papaya background");
+
+    assertThat(text.toString())
+        .isEqualTo("In this sentence this text doesn't have a papaya background");
+    assertThat(text).hasNoSpans();
+  }
+
+  @Test
   public void testParseWellFormedUnclosedEndAtCueEnd() throws Exception {
     Spanned text = parseCueText("An <u some trailing stuff>unclosed u tag with "
         + "<i>italic</i> inside");