Caption lines as separate cues

library/src/main/java/com/google/android/exoplayer2/text/eia608/Eia608CueBuilder.java

+package com.google.android.exoplayer2.text.eia608;
+
+import com.google.android.exoplayer2.text.Cue;
+import com.google.android.exoplayer2.util.Assertions;
+
+import android.text.Layout;
+import android.text.SpannableStringBuilder;
+import android.text.Spanned;
+import android.text.style.CharacterStyle;
+import android.text.style.ForegroundColorSpan;
+import android.text.style.StyleSpan;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * A Builder for EIA-608 cues.
+ */
+/* package */ final class Eia608CueBuilder {
+
+  private static final int BASE_ROW = 15;
+
+  /**
+   * The caption string.
+   */
+  private SpannableStringBuilder captionStringBuilder;
+
+  /**
+   * The caption styles to apply to the caption string.
+   */
+  private HashMap<Integer, CharacterStyle> captionStyles;
+
+  /**
+   * The row on which the Cue should be displayed.
+   */
+  private int row;
+
+  /**
+   * The indent of the cue - horizontal positioning.
+   */
+  private int indent;
+
+  /**
+   * The setTabOffset offset for the cue.
+   */
+  private int tabOffset;
+
+  public Eia608CueBuilder() {
+    row = BASE_ROW;
+    indent = 0;
+    tabOffset = 0;
+    captionStringBuilder = new SpannableStringBuilder();
+    captionStyles = new HashMap<>();
+  }
+
+  /**
+   * Sets the row for this cue.
+   * @param row the row to set.
+   */
+  public void setRow(int row) {
+    Assertions.checkArgument(row >= 1 && row <= 15);
+    this.row = row;
+  }
+
+  public int getRow() {
+    return row;
+  }
+
+  /**
+   * Rolls up the Cue one row.
+   * @return true if rolling was possible.
+   */
+  public boolean rollUp() {
+    if (row < 1) {
+      return false;
+    }
+    setRow(row - 1);
+    return true;
+  }
+
+  /**
+   * Sets the indent for this cue.
+   * @param indent an indent value, must be a multiple of 4 within the range [0,28]
+   */
+  public void setIndent(int indent) {
+    Assertions.checkArgument(indent % 4 == 0 && indent <= 28);
+    this.indent = indent;
+  }
+
+  public void tab(int tabs) {
+    tabOffset += tabs;
+  }
+
+  /**
+   * Indents the cue position with amountOfTabs.
+   * @param tabOffset the amount of tabs the cue position should be indented.
+   */
+  public void setTabOffset(int tabOffset) {
+    this.tabOffset = tabOffset;
+  }
+
+  /**
+   * Appends a character to the current Cue.
+   * @param character the character to append.
+   */
+  public void append(char character) {
+    captionStringBuilder.append(character);
+  }
+
+  /**
+   * Removes the last character of the caption string.
+   */
+  public void backspace() {
+    if (captionStringBuilder.length() > 0) {
+      captionStringBuilder.delete(captionStringBuilder.length() - 1, captionStringBuilder.length());
+    }
+  }
+
+  /**
+   * Opens a character style at the current cueIndex.
+   * Takes care of style priorities.
+   *
+   * @param style the style to set.
+   */
+  public void setCharacterStyle(CharacterStyle style) {
+    int startIndex = getSpanStartIndex();
+    // Close all open spans of the same type, and add a new one.
+    if (style instanceof ForegroundColorSpan) {
+      // Setting a foreground color clears the italics style.
+      closeSpan(StyleSpan.class); // Italics is a style span.
+    }
+    closeSpan(style.getClass());
+    captionStyles.put(startIndex, style);
+  }
+
+  /**
+   * Closes all open spans of the spansToApply class.
+   * @param spansToClose the class of which the spans should be closed.
+   */
+  private void closeSpan(Class<? extends CharacterStyle> spansToClose) {
+    for (Integer index : captionStyles.keySet()) {
+      CharacterStyle style = captionStyles.get(index);
+      if (spansToClose.isInstance(style)) {
+        if (index < captionStringBuilder.length()) {
+          captionStringBuilder.setSpan(style, index,
+            captionStringBuilder.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+        captionStyles.remove(index);
+      }
+    }
+  }
+
+  /**
+   * Applies all currently opened spans to the SpannableStringBuilder.
+   */
+  public void closeSpans() {
+    // Check if we have to do anything.
+    if (captionStyles.size() == 0) {
+      return;
+    }
+
+    for (Integer startIndex : captionStyles.keySet()) {
+      // There may be cases, e.g. when seeking where the startIndex becomes greater
+      // than what is actually in the string builder, in that case, just discard the span.
+      if (startIndex < captionStringBuilder.length()) {
+        CharacterStyle captionStyle = captionStyles.get(startIndex);
+        captionStringBuilder.setSpan(captionStyle, startIndex,
+          captionStringBuilder.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+      }
+      captionStyles.remove(startIndex);
+    }
+  }
+
+  public Cue build() {
+    closeSpans();
+    float cueLine = 10 + (5.33f * row);
+    float cuePosition = 10 + (2.5f * indent);
+    cuePosition = (tabOffset * 2.5f) + cuePosition;
+    return new Cue(captionStringBuilder, Layout.Alignment.ALIGN_NORMAL, cueLine / 100, Cue.LINE_TYPE_FRACTION,
+      Cue.ANCHOR_TYPE_START, cuePosition / 100, Cue.TYPE_UNSET, Cue.DIMEN_UNSET);
+  }
+
+  private int getSpanStartIndex() {
+    return captionStringBuilder.length() > 0 ? captionStringBuilder.length() - 1 : 0;
+  }
+
+  public static List<Cue> buildCues(List<Eia608CueBuilder> builders) {
+    if (builders.isEmpty()) {
+      return Collections.emptyList();
+    }
+    LinkedList<Cue> cues = new LinkedList<>();
+    for (Eia608CueBuilder builder : builders) {
+      if (builder.captionStringBuilder.length() == 0) {
+        continue;
+      }
+      cues.add(builder.build());
+    }
+    return cues;
+  }
+
+}

library/src/main/java/com/google/android/exoplayer2/text/eia608/Eia608Subtitle.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.text.eia608;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.text.Subtitle;
 
+import java.util.LinkedList;
 import java.util.List;
 
 /**
@@ -25,9 +26,13 @@ import java.util.List;
  */
 /* package */ final class Eia608Subtitle implements Subtitle {
 
-  private final List<Cue> cues;
+  private List<Cue> cues;
 
-  public Eia608Subtitle(List<Cue> cues) {
+  public Eia608Subtitle() {
+    cues = new LinkedList<>();
+  }
+
+  /* package */ void setCues(List<Cue> cues) {
     this.cues = cues;
   }
 

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

@@ -15,6 +15,10 @@
  */
 package com.google.android.exoplayer2.ui;
 
+import com.google.android.exoplayer2.text.CaptionStyleCompat;
+import com.google.android.exoplayer2.text.Cue;
+import com.google.android.exoplayer2.util.Util;
+
 import android.content.Context;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
@@ -30,9 +34,6 @@ import android.text.TextPaint;
 import android.text.TextUtils;
 import android.util.DisplayMetrics;
 import android.util.Log;
-import com.google.android.exoplayer2.text.CaptionStyleCompat;
-import com.google.android.exoplayer2.text.Cue;
-import com.google.android.exoplayer2.util.Util;
 
 /**
  * Paints subtitle {@link Cue}s.