addAnnotation method

Future<int> addAnnotation(int pageIndex, UPdfAnnotationSpec spec)

Implementation

Future<int> addAnnotation(int pageIndex, UPdfAnnotationSpec spec) async {
  final UPdfDict? page = await mutablePage(pageIndex);
  final UPdfRef? ref = await pageRef(pageIndex);
  if (page == null || ref == null) return -1;
  final int number = allocate();
  final Map<String, Object?> annotation = <String, Object?>{
    "Type": const UPdfName("Annot"),
    "Subtype": UPdfName(_subtypeFor(spec.style)),
    "Rect": <Object?>[spec.rect.left, spec.rect.top, spec.rect.right, spec.rect.bottom],
    "F": 4,
    "M": _dateString(DateTime.now()),
    "CA": spec.opacity,
    "C": _colorArray(spec.color),
    "P": ref,
    "NM": _text("u-${DateTime.now().microsecondsSinceEpoch}-$number"),
  };
  if (spec.contents.isNotEmpty) annotation["Contents"] = _text(spec.contents);
  if (spec.author.isNotEmpty) annotation["T"] = _text(spec.author);
  if (spec.title.isNotEmpty) annotation["Subj"] = _text(spec.title);
  if (spec.borderWidth > 0) annotation["BS"] = UPdfDict(<String, Object?>{"W": spec.borderWidth, "S": const UPdfName("S")});
  if (spec.quads.isNotEmpty) {
    final List<Object?> quadPoints = <Object?>[];
    for (final Rect quad in spec.quads) {
      quadPoints.addAll(<Object?>[quad.left, quad.bottom, quad.right, quad.bottom, quad.left, quad.top, quad.right, quad.top]);
    }
    annotation["QuadPoints"] = quadPoints;
  }
  if (spec.style == UPdfAnnotationStyle.ink && spec.inkPaths.isNotEmpty) {
    final List<Object?> inkList = <Object?>[];
    for (final List<Offset> path in spec.inkPaths) {
      final List<Object?> points = <Object?>[];
      for (final Offset point in path) {
        points.addAll(<Object?>[point.dx, point.dy]);
      }
      inkList.add(points);
    }
    annotation["InkList"] = inkList;
  }
  if (spec.style == UPdfAnnotationStyle.freeText) {
    annotation["DA"] = UPdfString(Uint8List.fromList("${_colorOperator(const Color(0xFF000000), stroke: false)} /Helv ${UPdfSerializer.number(spec.fontSize)} Tf".codeUnits));
    annotation["Q"] = spec.rtl ? 2 : 0;
  }
  final int appearanceNumber = allocate();
  final UPdfStream? appearance = await _buildAppearance(spec);
  if (appearance != null) {
    put(appearanceNumber, appearance);
    annotation["AP"] = UPdfDict(<String, Object?>{"N": UPdfRef(appearanceNumber, 0)});
  }
  put(number, UPdfDict(annotation));
  final Object? existing = await document.resolve(page["Annots"]);
  final List<Object?> annotations = existing is List<Object?> ? <Object?>[...existing] : <Object?>[];
  annotations.add(UPdfRef(number, 0));
  page["Annots"] = annotations;
  return number;
}