borderRadius property

@override List<Radius>? get borderRadius

Implementation

@override
List<Radius>? get borderRadius {
  // Fast path: if all corners are zero, no radii.
  final CSSBorderRadius tl = _borderTopLeftRadius ?? CSSBorderRadius.zero;
  final CSSBorderRadius tr = _borderTopRightRadius ?? CSSBorderRadius.zero;
  final CSSBorderRadius br = _borderBottomRightRadius ?? CSSBorderRadius.zero;
  final CSSBorderRadius bl = _borderBottomLeftRadius ?? CSSBorderRadius.zero;

  final bool hasAnyRadius = !(tl == CSSBorderRadius.zero && tr == CSSBorderRadius.zero &&
      br == CSSBorderRadius.zero && bl == CSSBorderRadius.zero);
  if (!hasAnyRadius) return null;

  // Cache to avoid recomputing per paint phase.
  // When any axis uses percentages, the result depends on the border box size.
  final bool tlPct = tl.x.isPercentage || tl.y.isPercentage;
  final bool trPct = tr.x.isPercentage || tr.y.isPercentage;
  final bool brPct = br.x.isPercentage || br.y.isPercentage;
  final bool blPct = bl.x.isPercentage || bl.y.isPercentage;
  final bool anyPct = tlPct || trPct || brPct || blPct;

  final double? bw = borderBoxWidth ?? borderBoxLogicalWidth;
  final double? bh = borderBoxHeight ?? borderBoxLogicalHeight;

  // Reuse cached radii when inputs are identical and the size anchor (for %) is unchanged.
  if (_cachedComputedBorderRadius != null &&
      identical(_cachedTLRef, _borderTopLeftRadius) &&
      identical(_cachedTRRef, _borderTopRightRadius) &&
      identical(_cachedBRRef, _borderBottomRightRadius) &&
      identical(_cachedBLRef, _borderBottomLeftRadius) &&
      (!anyPct || (_cachedBorderRadiusW == bw && _cachedBorderRadiusH == bh))) {
    return _cachedComputedBorderRadius;
  }

  final radii = <Radius>[
    tl.computedRadius,
    tr.computedRadius,
    br.computedRadius,
    bl.computedRadius,
  ];

  _cachedComputedBorderRadius = radii;
  _cachedBorderRadiusW = anyPct ? bw : _cachedBorderRadiusW; // only bind size when needed
  _cachedBorderRadiusH = anyPct ? bh : _cachedBorderRadiusH;
  _cachedTLRef = _borderTopLeftRadius;
  _cachedTRRef = _borderTopRightRadius;
  _cachedBRRef = _borderBottomRightRadius;
  _cachedBLRef = _borderBottomLeftRadius;

  if (DebugFlags.enableBorderRadiusLogs) {
    try {
      final el = target;
      renderingLogger.finer('[BorderRadius] compute for <${el.tagName.toLowerCase()}> '
          'borderBox=${(bw)?.toStringAsFixed(2) ?? 'null'}×${(bh)?.toStringAsFixed(2) ?? 'null'} '
          'tl=(${radii[0].x.toStringAsFixed(2)},${radii[0].y.toStringAsFixed(2)}) '
          'tr=(${radii[1].x.toStringAsFixed(2)},${radii[1].y.toStringAsFixed(2)}) '
          'br=(${radii[2].x.toStringAsFixed(2)},${radii[2].y.toStringAsFixed(2)}) '
          'bl=(${radii[3].x.toStringAsFixed(2)},${radii[3].y.toStringAsFixed(2)})');
    } catch (_) {}
  }

  return radii;
}