diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttCue.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttCue.java | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttCue.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttCue.java new file mode 100644 index 0000000000..af701d8f54 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttCue.java @@ -0,0 +1,319 @@ +/* + * Copyright (C) 2016 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. + */ +package org.mozilla.thirdparty.com.google.android.exoplayer2.text.webvtt; + +import static java.lang.annotation.RetentionPolicy.SOURCE; + +import android.text.Layout.Alignment; +import androidx.annotation.IntDef; +import androidx.annotation.Nullable; +import org.mozilla.thirdparty.com.google.android.exoplayer2.text.Cue; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log; +import java.lang.annotation.Documented; +import java.lang.annotation.Retention; + +/** A representation of a WebVTT cue. */ +public final class WebvttCue extends Cue { + + private static final float DEFAULT_POSITION = 0.5f; + + public final long startTime; + public final long endTime; + + private WebvttCue( + long startTime, + long endTime, + CharSequence text, + @Nullable Alignment textAlignment, + float line, + @Cue.LineType int lineType, + @Cue.AnchorType int lineAnchor, + float position, + @Cue.AnchorType int positionAnchor, + float width) { + super(text, textAlignment, line, lineType, lineAnchor, position, positionAnchor, width); + this.startTime = startTime; + this.endTime = endTime; + } + + /** + * Returns whether or not this cue should be placed in the default position and rolled-up with + * the other "normal" cues. + * + * @return Whether this cue should be placed in the default position. + */ + public boolean isNormalCue() { + return (line == DIMEN_UNSET && position == DEFAULT_POSITION); + } + + /** Builder for WebVTT cues. */ + @SuppressWarnings("hiding") + public static class Builder { + + /** + * Valid values for {@link #setTextAlignment(int)}. + * + * <p>We use a custom list (and not {@link Alignment} directly) in order to include both {@code + * START}/{@code LEFT} and {@code END}/{@code RIGHT}. The distinction is important for {@link + * #derivePosition(int)}. + * + * <p>These correspond to the valid values for the 'align' cue setting in the <a + * href="https://www.w3.org/TR/webvtt1/#webvtt-cue-text-alignment">WebVTT spec</a>. + */ + @Documented + @Retention(SOURCE) + @IntDef({ + TEXT_ALIGNMENT_START, + TEXT_ALIGNMENT_CENTER, + TEXT_ALIGNMENT_END, + TEXT_ALIGNMENT_LEFT, + TEXT_ALIGNMENT_RIGHT + }) + public @interface TextAlignment {} + /** + * See WebVTT's <a + * href="https://www.w3.org/TR/webvtt1/#webvtt-cue-start-alignment">align:start</a>. + */ + public static final int TEXT_ALIGNMENT_START = 1; + + /** + * See WebVTT's <a + * href="https://www.w3.org/TR/webvtt1/#webvtt-cue-center-alignment">align:center</a>. + */ + public static final int TEXT_ALIGNMENT_CENTER = 2; + + /** + * See WebVTT's <a href="https://www.w3.org/TR/webvtt1/#webvtt-cue-end-alignment">align:end</a>. + */ + public static final int TEXT_ALIGNMENT_END = 3; + + /** + * See WebVTT's <a href="https://www.w3.org/TR/webvtt1/#webvtt-cue-left-alignment">align:left</a>. + */ + public static final int TEXT_ALIGNMENT_LEFT = 4; + + /** + * See WebVTT's <a + * href="https://www.w3.org/TR/webvtt1/#webvtt-cue-right-alignment">align:right</a>. + */ + public static final int TEXT_ALIGNMENT_RIGHT = 5; + + private static final String TAG = "WebvttCueBuilder"; + + private long startTime; + private long endTime; + @Nullable private CharSequence text; + @TextAlignment private int textAlignment; + private float line; + // Equivalent to WebVTT's snap-to-lines flag: + // https://www.w3.org/TR/webvtt1/#webvtt-cue-snap-to-lines-flag + @LineType private int lineType; + @AnchorType private int lineAnchor; + private float position; + @AnchorType private int positionAnchor; + private float width; + + // Initialization methods + + // Calling reset() is forbidden because `this` isn't initialized. This can be safely + // suppressed because reset() only assigns fields, it doesn't read any. + @SuppressWarnings("nullness:method.invocation.invalid") + public Builder() { + reset(); + } + + public void reset() { + startTime = 0; + endTime = 0; + text = null; + // Default: https://www.w3.org/TR/webvtt1/#webvtt-cue-text-alignment + textAlignment = TEXT_ALIGNMENT_CENTER; + line = Cue.DIMEN_UNSET; + // Defaults to NUMBER (true): https://www.w3.org/TR/webvtt1/#webvtt-cue-snap-to-lines-flag + lineType = Cue.LINE_TYPE_NUMBER; + // Default: https://www.w3.org/TR/webvtt1/#webvtt-cue-line-alignment + lineAnchor = Cue.ANCHOR_TYPE_START; + position = Cue.DIMEN_UNSET; + positionAnchor = Cue.TYPE_UNSET; + // Default: https://www.w3.org/TR/webvtt1/#webvtt-cue-size + width = 1.0f; + } + + // Construction methods. + + public WebvttCue build() { + line = computeLine(line, lineType); + + if (position == Cue.DIMEN_UNSET) { + position = derivePosition(textAlignment); + } + + if (positionAnchor == Cue.TYPE_UNSET) { + positionAnchor = derivePositionAnchor(textAlignment); + } + + width = Math.min(width, deriveMaxSize(positionAnchor, position)); + + return new WebvttCue( + startTime, + endTime, + Assertions.checkNotNull(text), + convertTextAlignment(textAlignment), + line, + lineType, + lineAnchor, + position, + positionAnchor, + width); + } + + public Builder setStartTime(long time) { + startTime = time; + return this; + } + + public Builder setEndTime(long time) { + endTime = time; + return this; + } + + public Builder setText(CharSequence text) { + this.text = text; + return this; + } + + public Builder setTextAlignment(@TextAlignment int textAlignment) { + this.textAlignment = textAlignment; + return this; + } + + public Builder setLine(float line) { + this.line = line; + return this; + } + + public Builder setLineType(@LineType int lineType) { + this.lineType = lineType; + return this; + } + + public Builder setLineAnchor(@AnchorType int lineAnchor) { + this.lineAnchor = lineAnchor; + return this; + } + + public Builder setPosition(float position) { + this.position = position; + return this; + } + + public Builder setPositionAnchor(@AnchorType int positionAnchor) { + this.positionAnchor = positionAnchor; + return this; + } + + public Builder setWidth(float width) { + this.width = width; + return this; + } + + // https://www.w3.org/TR/webvtt1/#webvtt-cue-line + private static float computeLine(float line, @LineType int lineType) { + if (line != Cue.DIMEN_UNSET + && lineType == Cue.LINE_TYPE_FRACTION + && (line < 0.0f || line > 1.0f)) { + return 1.0f; // Step 1 + } else if (line != Cue.DIMEN_UNSET) { + // Step 2: Do nothing, line is already correct. + return line; + } else if (lineType == Cue.LINE_TYPE_FRACTION) { + return 1.0f; // Step 3 + } else { + // Steps 4 - 10 (stacking multiple simultaneous cues) are handled by WebvttSubtitle#getCues + // and WebvttCue#isNormalCue. + return DIMEN_UNSET; + } + } + + // https://www.w3.org/TR/webvtt1/#webvtt-cue-position + private static float derivePosition(@TextAlignment int textAlignment) { + switch (textAlignment) { + case TEXT_ALIGNMENT_LEFT: + return 0.0f; + case TEXT_ALIGNMENT_RIGHT: + return 1.0f; + case TEXT_ALIGNMENT_START: + case TEXT_ALIGNMENT_CENTER: + case TEXT_ALIGNMENT_END: + default: + return DEFAULT_POSITION; + } + } + + // https://www.w3.org/TR/webvtt1/#webvtt-cue-position-alignment + @AnchorType + private static int derivePositionAnchor(@TextAlignment int textAlignment) { + switch (textAlignment) { + case TEXT_ALIGNMENT_LEFT: + case TEXT_ALIGNMENT_START: + return Cue.ANCHOR_TYPE_START; + case TEXT_ALIGNMENT_RIGHT: + case TEXT_ALIGNMENT_END: + return Cue.ANCHOR_TYPE_END; + case TEXT_ALIGNMENT_CENTER: + default: + return Cue.ANCHOR_TYPE_MIDDLE; + } + } + + @Nullable + private static Alignment convertTextAlignment(@TextAlignment int textAlignment) { + switch (textAlignment) { + case TEXT_ALIGNMENT_START: + case TEXT_ALIGNMENT_LEFT: + return Alignment.ALIGN_NORMAL; + case TEXT_ALIGNMENT_CENTER: + return Alignment.ALIGN_CENTER; + case TEXT_ALIGNMENT_END: + case TEXT_ALIGNMENT_RIGHT: + return Alignment.ALIGN_OPPOSITE; + default: + Log.w(TAG, "Unknown textAlignment: " + textAlignment); + return null; + } + } + + // Step 2 here: https://www.w3.org/TR/webvtt1/#processing-cue-settings + private static float deriveMaxSize(@AnchorType int positionAnchor, float position) { + switch (positionAnchor) { + case Cue.ANCHOR_TYPE_START: + return 1.0f - position; + case Cue.ANCHOR_TYPE_END: + return position; + case Cue.ANCHOR_TYPE_MIDDLE: + if (position <= 0.5f) { + return position * 2; + } else { + return (1.0f - position) * 2; + } + case Cue.TYPE_UNSET: + default: + throw new IllegalStateException(String.valueOf(positionAnchor)); + } + } + } +} |