ModifyingExistingFileContent.js

var muhammara = require("../lib/muhammara");

// [look...not gonna write it 100% right...you JS experts can probably write this better]
// PDFComment object
function PDFComment(
  inText,
  inCommentator,
  inPosition,
  inColor,
  flag,
  inReplyTo,
) {
  this.time = new Date();
  this.text = inText;
  this.commentator = inCommentator;
  this.position = inPosition;
  this.color = inColor;
  this.replyTo = inReplyTo;
  this.objectID = 0;
  this.flag = flag;
}

// PDFCommentWriter object
function PDFCommentWriter(inPDFWriter) {
  this.pdfWriter = inPDFWriter;
}

PDFCommentWriter.prototype.writeCommentTree = function (inComment) {
  this._writeCommentsTree(inComment).first;
};

PDFCommentWriter.prototype._writeCommentsTree = function (inComment) {
  var repliedTo = 0;
  var result;

  // if already written, let go
  if (inComment.objectID != 0) {
    return inComment.objectID;
  }

  // if has referred comment, write it first
  if (inComment.replyTo) {
    repliedTo = this._writeCommentsTree(inComment.replyTo);
  }

  var objectsContext = this.pdfWriter.getObjectsContext();
  result = objectsContext.startNewIndirectObject();
  var dictionaryContext = objectsContext.startDictionary();

  dictionaryContext
    .writeKey("Type")
    .writeNameValue("Annot")
    .writeKey("Subtype")
    .writeNameValue("Text")
    .writeKey("Rect")
    .writeRectangleValue(inComment.position) // when implementing allow also 4 numbers input
    .writeKey("Contents")
    .writeLiteralStringValue(
      this.pdfWriter.createPDFTextString(inComment.text).toBytesArray(),
    )
    .writeKey("C");

  objectsContext.startArray();
  inComment.color.forEach(function (element, index, array) {
    objectsContext.writeNumber(element / 255);
  });
  objectsContext.endArray(muhammara.eTokenSeparatorEndLine);

  dictionaryContext
    .writeKey("T")
    .writeLiteralStringValue(
      this.pdfWriter.createPDFTextString(inComment.commentator).toBytesArray(),
    )
    .writeKey("M")
    .writeLiteralStringValue(
      this.pdfWriter.createPDFDate(inComment.time).toString(),
    );

  if (inComment.replyTo) {
    dictionaryContext
      .writeKey("IRT")
      .writeObjectReferenceValue(repliedTo)
      .writeKey("RT")
      .writeNameValue("R");
  }

  dictionaryContext
    .writeKey("Open")
    .writeBooleanValue(false)
    .writeKey("Name")
    .writeNameValue("Comment")
    .writeKey("F")
    .writeNumberValue(getFlagBitNumberByName(inComment.flag));

  objectsContext.endDictionary(dictionaryContext).endIndirectObject();

  inComment.objectID = result;
  return result;
};

function getFlagBitNumberByName(name) {
  name = name || "";
  // 12.5.3 Annotation Flags
  switch (name.toLowerCase()) {
    case "invisible":
      return 1;
    case "hidden":
      return 2;
    case "print":
      return 4;
    case "nozoom":
      return 8;
    case "norotate":
      return 16;
    case "noview":
      return 32;
    case "readonly":
      return 64;
    case "locked":
      return 128;
    case "togglenoview":
      return 256;
    // 1.7+
    // case 'lockedcontents':
    //     return 512;
    default:
      return 0;
  }
}

describe("ModifyingExistingFileContent", function () {
  var inPDFWriter;

  before(function () {
    inPDFWriter = muhammara.createWriterToModify(
      __dirname + "/TestMaterials/AddedPage.pdf",
      {
        modifiedFilePath:
          __dirname + "/output/ModifyingExistingFileContent.pdf",
      },
    );
  });
  describe("page size modification", function () {
    it("should complete without error", function () {
      var copyingContext = inPDFWriter.createPDFCopyingContextForModifiedFile();
      var thirdPageID = copyingContext
        .getSourceDocumentParser()
        .getPageObjectID(2);
      var thirdPageObject = copyingContext
        .getSourceDocumentParser()
        .parsePage(2)
        .getDictionary()
        .toJSObject();
      var objectsContext = inPDFWriter.getObjectsContext();

      objectsContext.startModifiedIndirectObject(thirdPageID);
      var modifiedPageObject = inPDFWriter
        .getObjectsContext()
        .startDictionary();

      Object.getOwnPropertyNames(thirdPageObject).forEach(
        function (element, index, array) {
          if (element != "MediaBox") {
            modifiedPageObject.writeKey(element);
            copyingContext.copyDirectObjectAsIs(thirdPageObject[element]);
          }
        },
      );
      modifiedPageObject.writeKey("MediaBox");
      objectsContext
        .startArray()
        .writeNumber(0)
        .writeNumber(0)
        .writeNumber(500)
        .writeNumber(500)
        .endArray()
        .endLine()
        .endDictionary(modifiedPageObject)
        .endIndirectObject();
    });
  });
  describe("adding comments", function () {
    it("should complete without error", function () {
      var commentWriter = new PDFCommentWriter(inPDFWriter);
      var aComment = new PDFComment(
        "a very important text",
        "someone",
        [100, 500, 200, 600],
        [255, 0, 0],
        "noview",
      );
      commentWriter.writeCommentTree(aComment);
      var bComment = new PDFComment(
        "I have nothing to say about this",
        "someone",
        [100, 100, 200, 200],
        [255, 0, 0],
        "readOnly",
      );
      var cComment = new PDFComment(
        "yeah. me too. it's just perfect",
        "Someone else",
        [150, 150, 250, 250],
        [0, 255, 0],
        "nozoom",
        bComment,
      );
      commentWriter.writeCommentTree(cComment);

      var copyingContext = inPDFWriter.createPDFCopyingContextForModifiedFile();

      var fourthPageID = copyingContext
        .getSourceDocumentParser()
        .getPageObjectID(3);
      var fourthPageObject = copyingContext
        .getSourceDocumentParser()
        .parsePage(3)
        .getDictionary()
        .toJSObject();
      var objectsContext = inPDFWriter.getObjectsContext();

      objectsContext.startModifiedIndirectObject(fourthPageID);
      var modifiedPageObject = inPDFWriter
        .getObjectsContext()
        .startDictionary();

      Object.getOwnPropertyNames(fourthPageObject).forEach(
        function (element, index, array) {
          if (element != "Annots") {
            modifiedPageObject.writeKey(element);
            copyingContext.copyDirectObjectAsIs(fourthPageObject[element]);
          }
        },
      );

      modifiedPageObject.writeKey("Annots");
      objectsContext.startArray();
      objectsContext.writeIndirectObjectReference(aComment.objectID);
      objectsContext.writeIndirectObjectReference(bComment.objectID);
      objectsContext.writeIndirectObjectReference(cComment.objectID);
      objectsContext
        .endArray()
        .endLine()
        .endDictionary(modifiedPageObject)
        .endIndirectObject();
    });
  });

  after(function () {
    inPDFWriter.end();
  });
});