Method rotateHints

content_scripts/link_hints.js:625–691

()

  // Rotate the hints' z-index values so that hidden hints become visible.
  rotateHints() {
    // Partitions array into two arrays, based on the bool return value of predicate.
    function partition(array, predicate) {
      const a = [];
      const b = [];
      for (const item of array) {
        const target = predicate(item) ? a : b;
        target.push(item);
      }
      return [a, b];
    }

    // Get local, visible hint markers.
    const [localMarkers, otherMarkers] = partition(
      this.hintMarkers,
      (m) => m.isLocalMarker() && (m.element.style.display !== "none"),
    );

    // Fill in the markers' rects, if necessary.
    for (const m of localMarkers) {
      if (m.markerRect == null) {
        m.markerRect = m.element.getClientRects()[0];
      }
    }

    // Calculate the overlapping groups of hints. We call each group a "stack". This is O(n^2).
    let stacks = [];
    for (const m of localMarkers) {
      let stackForThisMarker = null;
      const results = [];
      for (const stack of stacks) {
        const markerOverlapsThisStack = this.markerOverlapsStack(m, stack);
        if (markerOverlapsThisStack && (stackForThisMarker == null)) {
          // We've found an existing stack for this marker.
          stack.push(m);
          stackForThisMarker = stack;
          results.push(stack);
        } else if (markerOverlapsThisStack && (stackForThisMarker != null)) {
          // This marker overlaps a second (or subsequent) stack; merge that stack into
          // stackForThisMarker and discard it.
          stackForThisMarker.push(...stack);
          continue; // Discard this stack.
        } else {
          stack; // Keep this stack.
          results.push(stack);
        }
      }
      stacks = results;

      if (stackForThisMarker == null) {
        stacks.push([m]);
      }
    }

    let newMarkers = [];
    for (let stack of stacks) {
      if (stack.length > 1) {
        // Push the last element to the beginning.