[Backport] Feature: Divide player seekbar by chapters

app/src/main/java/org/schabi/newpipe/player/ui/VideoPlayerUi.java

@@ -28,6 +28,7 @@
 import android.os.Looper;
 import android.util.Log;
 import android.view.GestureDetector;
+import android.view.HapticFeedbackConstants;
 import android.view.Gravity;
 import android.view.KeyEvent;
 import android.view.Menu;
@@ -66,7 +67,9 @@
 import org.schabi.newpipe.extractor.MediaFormat;
 import org.schabi.newpipe.extractor.stream.AudioStream;
 import org.schabi.newpipe.extractor.stream.StreamInfo;
+import org.schabi.newpipe.extractor.stream.StreamSegment;
 import org.schabi.newpipe.extractor.stream.VideoStream;
+import org.schabi.newpipe.views.ChaptersSeekBar;
 import org.schabi.newpipe.fragments.detail.VideoDetailFragment;
 import org.schabi.newpipe.ktx.AnimationType;
 import org.schabi.newpipe.player.Player;
@@ -86,6 +89,7 @@
 import org.schabi.newpipe.util.external_communication.ShareUtils;
 import org.schabi.newpipe.views.player.PlayerFastSeekOverlay;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
@@ -148,6 +152,11 @@ private enum PlayButtonAction {
     private final SeekbarPreviewThumbnailHolder seekbarPreviewThumbnailHolder =
             new SeekbarPreviewThumbnailHolder();
 
+    @NonNull
+    private List<StreamSegment> currentChapters = Collections.emptyList();
+    @Nullable
+    private StreamSegment lastChapterForHaptic = null;
+
 
     /*//////////////////////////////////////////////////////////////////////////
     // Constructor, setup, destroy
@@ -586,6 +595,18 @@ public void onProgressChanged(final SeekBar seekBar, final int progress,
                         binding.currentSeekbarPreviewThumbnail,
                         binding.subtitleView::getWidth);
 
+        // Chapter title tooltip + haptic feedback at chapter boundaries
+        if (!currentChapters.isEmpty()) {
+            final StreamSegment chapter = getChapterAtMs(progress);
+            if (chapter != null && chapter.getTitle() != null) {
+                binding.currentChapterTitle.setText(chapter.getTitle());
+            }
+            if (chapter != lastChapterForHaptic) {
+                lastChapterForHaptic = chapter;
+                seekBar.performHapticFeedback(HapticFeedbackConstants.CLOCK_TICK);
+            }
+        }
+
         adjustSeekbarPreviewContainer();
     }
 
@@ -639,6 +660,10 @@ public void onStartTrackingTouch(final SeekBar seekBar) {
                 AnimationType.SCALE_AND_ALPHA);
         animate(binding.currentSeekbarPreviewThumbnail, true, DEFAULT_CONTROLS_DURATION,
                 AnimationType.SCALE_AND_ALPHA);
+        if (!currentChapters.isEmpty()) {
+            animate(binding.currentChapterTitle, true, DEFAULT_CONTROLS_DURATION,
+                    AnimationType.SCALE_AND_ALPHA);
+        }
     }
 
     @Override // seekbar listener
@@ -655,6 +680,7 @@ public void onStopTrackingTouch(final SeekBar seekBar) {
         binding.playbackCurrentTime.setText(getTimeString(seekBar.getProgress()));
         animate(binding.currentDisplaySeek, false, 200, AnimationType.SCALE_AND_ALPHA);
         animate(binding.currentSeekbarPreviewThumbnail, false, 200, AnimationType.SCALE_AND_ALPHA);
+        animate(binding.currentChapterTitle, false, 200, AnimationType.SCALE_AND_ALPHA);
 
         if (player.getCurrentState() == STATE_PAUSED_SEEK) {
             player.changeState(STATE_BUFFERING);
@@ -665,6 +691,25 @@ public void onStopTrackingTouch(final SeekBar seekBar) {
 
         showControlsThenHide();
     }
+
+    /**
+     * Returns the chapter active at the given playback position, or {@code null} if
+     * {@code currentChapters} is empty.
+     *
+     * @param positionMs playback position in milliseconds
+     * @return the {@link StreamSegment} whose window contains {@code positionMs}
+     */
+    @Nullable
+    private StreamSegment getChapterAtMs(final long positionMs) {
+        StreamSegment result = null;
+        for (final StreamSegment seg : currentChapters) {
+            if (seg.getStartTimeSeconds() * 1000L > positionMs) {
+                break;
+            }
+            result = seg;
+        }
+        return result;
+    }
     //endregion
 
 
@@ -1021,6 +1066,14 @@ public void onMetadataChanged(@NonNull final StreamInfo info) {
         binding.channelTextView.setText(info.getUploaderName());
 
         this.seekbarPreviewThumbnailHolder.resetFrom(player.getContext(), info.getPreviewFrames());
+
+        // Chapter markers on seekbar
+        currentChapters = info.getStreamSegments() != null
+                ? info.getStreamSegments() : Collections.emptyList();
+        lastChapterForHaptic = null;
+        ((ChaptersSeekBar) binding.playbackSeekBar)
+                .setChapters(currentChapters, info.getDuration());
+        binding.currentChapterTitle.setVisibility(View.GONE);
     }
 
     private void updateStreamRelatedViews() {

app/src/main/java/org/schabi/newpipe/views/ChaptersSeekBar.java

@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) NewPipe Contributors
+ * ChaptersSeekBar.java is part of NewPipe.
+ *
+ * NewPipe is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * NewPipe is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with NewPipe.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.schabi.newpipe.views;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffXfermode;
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import org.schabi.newpipe.extractor.stream.StreamSegment;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A {@link FocusAwareSeekBar} that renders narrow transparent gaps at chapter boundaries,
+ * giving the seekbar a segmented "chopped" appearance.
+ * Call {@link #setChapters(List, long)} whenever a new stream loads.
+ */
+public final class ChaptersSeekBar extends FocusAwareSeekBar {
+
+    private static final float GAP_WIDTH_DP = 2f;
+
+    private final Paint gapPaint = new Paint();
+
+    @NonNull private List<StreamSegment> chapters = Collections.emptyList();
+    private long durationSeconds = 0;
+
+    public ChaptersSeekBar(@NonNull final Context context) {
+        super(context);
+        init();
+    }
+
+    public ChaptersSeekBar(@NonNull final Context context,
+                           @Nullable final AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+    public ChaptersSeekBar(@NonNull final Context context,
+                           @Nullable final AttributeSet attrs,
+                           final int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        init();
+    }
+
+    private void init() {
+        gapPaint.setStyle(Paint.Style.FILL);
+        gapPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
+    }
+
+    /**
+     * Stores chapter data for rendering segment gaps.
+     *
+     * @param newChapters     list of {@link StreamSegment}s; may be empty but never null
+     * @param newDurationSecs total duration in seconds; used to compute fractional positions
+     */
+    public void setChapters(@NonNull final List<StreamSegment> newChapters,
+                            final long newDurationSecs) {
+        chapters = newChapters;
+        durationSeconds = newDurationSecs;
+        invalidate();
+    }
+
+    @Override
+    protected void onDraw(@NonNull final Canvas canvas) {
+        if (chapters.isEmpty() || durationSeconds <= 0) {
+            super.onDraw(canvas);
+            return;
+        }
+
+        // Draw the seekbar into an offscreen layer so CLEAR mode can punch transparent gaps
+        final int sc = canvas.saveLayer(null, null);
+        super.onDraw(canvas);
+
+        final float density = getResources().getDisplayMetrics().density;
+        final float gapHalfWidth = (GAP_WIDTH_DP * density) / 2f;
+        final int paddingLeft = getPaddingLeft();
+        final float trackWidth = getWidth() - paddingLeft - getPaddingRight();
+
+        if (trackWidth > 0) {
+            for (final StreamSegment seg : chapters) {
+                final int startSec = seg.getStartTimeSeconds();
+                // Skip the very first position and anything at or past the end
+                if (startSec <= 0 || startSec >= durationSeconds) {
+                    continue;
+                }
+                final float x = paddingLeft + (startSec / (float) durationSeconds) * trackWidth;
+                canvas.drawRect(x - gapHalfWidth, 0, x + gapHalfWidth, getHeight(), gapPaint);
+            }
+        }
+
+        canvas.restoreToCount(sc);
+
+        // Redraw the thumb on top so it visually overlaps the gaps
+        final Drawable thumb = getThumb();
+        if (thumb != null) {
+            final int thumbSave = canvas.save();
+            canvas.translate(getPaddingLeft() - getThumbOffset(), getPaddingTop());
+            thumb.draw(canvas);
+            canvas.restoreToCount(thumbSave);
+        }
+    }
+}

app/src/main/java/org/schabi/newpipe/views/FocusAwareSeekBar.java

@@ -33,7 +33,7 @@
  * (onStartTrackingTouch/onStopTrackingTouch), so existing code does not need to be changed to
  * work with it.
   */
-public final class FocusAwareSeekBar extends AppCompatSeekBar {
+public class FocusAwareSeekBar extends AppCompatSeekBar {
     private NestedListener listener;
 
     private ViewTreeObserver treeObserver;

app/src/main/res/layout/player.xml

@@ -415,6 +415,23 @@
                     android:orientation="vertical"
                     android:paddingBottom="12dp">
 
+                    <org.schabi.newpipe.views.NewPipeTextView
+                        android:id="@+id/currentChapterTitle"
+                        android:layout_width="wrap_content"
+                        android:layout_height="wrap_content"
+                        android:background="#60000000"
+                        android:ellipsize="end"
+                        android:maxLines="1"
+                        android:paddingLeft="5dp"
+                        android:paddingRight="5dp"
+                        android:paddingBottom="2dp"
+                        android:textColor="@android:color/white"
+                        android:textSize="12sp"
+                        android:visibility="gone"
+                        tools:ignore="RtlHardcoded"
+                        tools:text="Introduction"
+                        tools:visibility="visible" />
+
                     <org.schabi.newpipe.views.NewPipeTextView
                         android:id="@+id/currentDisplaySeek"
                         android:layout_width="wrap_content"
@@ -467,7 +484,7 @@
                     tools:text="1:06:29" />
 
 
-                <org.schabi.newpipe.views.FocusAwareSeekBar
+                <org.schabi.newpipe.views.ChaptersSeekBar
                     android:id="@+id/playbackSeekBar"
                     style="@style/Widget.AppCompat.SeekBar"
                     android:layout_width="0dp"