collectReplayMaskRects static method

List<Map<String, int>> collectReplayMaskRects(double pixRatio, { Set<String> types = const {}, })

Pixel rects of every auto-masked widget plus every PlotlineSensitive, for session replay masking.

Implementation

static List<Map<String, int>> collectReplayMaskRects(double pixRatio, {Set<String> types = const {}}) {
  final rects = <Map<String, int>>[];
  void add(BuildContext c) {
    final box = c.findRenderObject();
    if (box is! RenderBox || !box.attached || !box.hasSize) return;
    final full = box.localToGlobal(Offset.zero) & box.size;
    var r = full;
    // Clip to every enclosing scroll viewport so scrolled content isn't masked over app bars / nav.
    // The paint clip is null for Clip.none viewports, which still paint (and must mask) overflow.
    try {
      RenderObject child = box;
      for (var p = box.parent; p is RenderObject; child = p, p = p.parent) {
        if (p is RenderBox && p is RenderAbstractViewport && p.hasSize) {
          final clip = p.describeApproximatePaintClip(child);
          if (clip != null) r = r.intersect(clip.shift(p.localToGlobal(Offset.zero)));
        }
      }
    } catch (e) {
      r = full; // never drop a mask because clipping failed; fall back to the full rect
      plotlineDebugLog("Error clipping replay mask rect: $e");
    }
    if (r.width <= 0 || r.height <= 0) return;
    rects.add({
      "x": (r.left * pixRatio).round(),
      "y": (r.top * pixRatio).round(),
      "w": (r.width * pixRatio).round(),
      "h": (r.height * pixRatio).round(),
    });
  }
  void walk(Element e) {
    if (_isAutoMasked(e.widget, types)) { add(e); return; }
    e.visitChildren(walk);
  }
  // ponytail: full tree walk once per capture; cache per frame if a huge tree ever shows up in profiles
  if (types.isNotEmpty) WidgetsBinding.instance.rootElement?.visitChildren(walk);
  PlotlineSensitive.contexts.forEach(add);
  return rects;
}