How to add a TextField if there is already an existing TextField in ABCPDF?

Question

It's fairly straight-forward to add a TextField using ABCPDF:

public FormField AddTextField(string inRect, string inName, string inText)
{
    int fieldId = mDoc.AddObject("<</Type /Annot /Subtype /Widget /F 4 /FT /Tx /Ff 4096 /Q 1>>");
    mDoc.SetInfo(fieldId, "/V:Text", inText);
    RegisterField(fieldId, inName, inRect);
    return new FormField(fieldId, mDoc);
}

With this as the implementation:

FormField text = AddTextField("40 530 300 580", "TextField1", "Hello World!");
text.DefaultAppearance = "/TimesRoman 36 Tf 0 0 1 rg";
text.BorderColor = "0 0 0";
text.FillColor = "220 220 220";
text.TextAlign = "Left";

If I need to add two fields that have the same name, it's a little more complex:

public int AddGroupField(FormField[] inKids, string inName, string inValue)
{
    if (inKids.Length == 0)
        throw new Exception("Cannot have a group field with no kids");
    string ft = null, dv = null;
    int fieldId = mDoc.AddObject("<< /Kids [] >>");
    foreach (FormField kid in inKids)
    {
        mDoc.SetInfo(fieldId, "/Kids[]:Ref", kid.Id.ToString());
        mDoc.SetInfo(kid.Id, "/Parent:Ref", fieldId);
        if (ft == null)
            ft = mDoc.GetInfo(kid.Id, "/FT");
        if (dv == null)
            dv = mDoc.GetInfo(kid.Id, "/DV");
        mDoc.SetInfo(kid.Id, "/FT:Del", "");
        mDoc.SetInfo(kid.Id, "/V:Del", "");
        mDoc.SetInfo(kid.Id, "/DV:Del", "");
    }
    mDoc.SetInfo(fieldId, "/FT", ft);
    mDoc.SetInfo(fieldId, "/T:Text", inName);
    mDoc.SetInfo(fieldId, "/V:Text", inValue);
    if (dv != null)
        mDoc.SetInfo(fieldId, "/DV:Text", dv);
    int eid = mDoc.GetInfoInt(mDoc.Root, "/AcroForm:Ref");
    mDoc.SetInfo(eid, "/Fields*[]:Ref", fieldId);
    return fieldId;
}

With this as the implementation:

FormField[] kids = new FormField[2];
kids[0] = AddTextField("40 230 300 280", null, null);
kids[1] = AddTextField("40 170 300 220", null, null);
int id = AddGroupField(kids, "TextField1", "Hello World!");

However, I'm having issues with adding a TextField to a PDF where a TextField already exists with that same name. So, for example, if my PDF already has a field named "TextField1" and then I want to add another field with that same name, none of the above implementations will work.

You might look at a document which has duplicated fields, and then try to recreate it. — Max Wyss, Jul 03 '14 at 08:38
Yeah, I was going to try to look at the bits of the PDF and then edit those. Your idea sounds one level better than that. :) — RichC, Jul 03 '14 at 13:19
Well, if someone knows how it should look like, it is the document, if properly created… — Max Wyss, Jul 03 '14 at 18:43

score 3 · Accepted Answer · answered Jul 09 '14 at 13:16

I was able to get the answer from ABCPDF support. And as you can see, it's not exactly a simple process. I'm not sure anyone could just figure this out on their own without spending months and months of research on the PDF spec and the ABCPDF product.

public FormField AddTextField(string inRect, string inName, string inText)
{
    bool fieldAlreadyExists = mDoc.Form[inName] != null;

    int fieldId = mDoc.AddObject("<</Type /Annot /Subtype /Widget /F 4 /FT /Tx /Ff 4096 /Q 1>>");
    mDoc.SetInfo(fieldId, "/V:Text", inText);
    RegisterField(fieldId, inName, inRect);
    var field = new FormField(fieldId, mDoc);

    if (fieldAlreadyExists)
    {
        InteractiveForm form = new InteractiveForm(mDoc);
        form.AddFieldIntoExistingGroup(field, true);
    }

    return field;
}


private bool AddFieldIntoExistingGroup(FormField field, bool refreshForm)
{
    bool duplicatesFound = false;
    int acroFormID = mDoc.GetInfoInt(mDoc.Root, "/AcroForm:Ref");
    int parentID = mDoc.GetInfoInt(field.Id, "/Parent:Ref");
    ArrayAtom kids;
    if (parentID > 0)
    {
        kids = mDoc.ObjectSoup.Catalog.Resolve(Atom.GetItem(mDoc.ObjectSoup[parentID].Atom, "Kids")) as ArrayAtom;
    }
    else
    {
        kids = mDoc.ObjectSoup.Catalog.Resolve(Atom.GetItem(mDoc.ObjectSoup[acroFormID].Atom, "Fields")) as ArrayAtom;
    }
    Dictionary<string, List<IndirectObject>> items = new Dictionary<string, List<IndirectObject>>();
    for (int i = 0; i < kids.Count; i++)
    {
        IndirectObject io = mDoc.ObjectSoup.Catalog.ResolveObj(kids[i]);
        if (io == null)
        {
            continue; // shouldn't really happen
        }
        string name = mDoc.GetInfo(io.ID, "/T:Text");
        if (!items.ContainsKey(name))
        {
            items[name] = new List<IndirectObject>();
        }
        items[name].Add(io);
    }
    foreach (KeyValuePair<string, List<IndirectObject>> pair in items)
    {
        if (pair.Value.Count > 1)
        {
            duplicatesFound = true;
            // shift field down to be a child of a new field node
            int id = mDoc.AddObject("<< >>");
            if (parentID > 0)
            {
                mDoc.SetInfo(parentID, "/Kids[]:Ref", id);
                mDoc.SetInfo(id, "/Parent:Ref", parentID);
            }
            else
            {
                mDoc.SetInfo(acroFormID, "/Fields[]:Ref", id);
            }
            string[] dictEntries = new[] { "/FT", "/T", "/TU", "/Ff", "/V", "/DV" };
            foreach (IndirectObject io in pair.Value)
            {
                foreach (string dictEntry in dictEntries)
                {
                    string val = mDoc.GetInfo(io.ID, dictEntry);
                    if (!string.IsNullOrEmpty(val))
                    {
                        mDoc.SetInfo(id, dictEntry, val);
                        mDoc.SetInfo(io.ID, dictEntry + ":Del", "");
                    }
                }
                ArrayRemoveOneRefAtom(kids, io.ID);
                mDoc.SetInfo(id, "/Kids[]:Ref", io.ID);
                mDoc.SetInfo(io.ID, "/Parent:Ref", id);
            }
        }
    }
    if ((refreshForm) && (duplicatesFound))
    {
        mDoc.Form.Refresh();
    }
    return duplicatesFound;
}

private static bool ArrayRemoveOneRefAtom(ArrayAtom array, int id)
{
    if (array != null)
    {
        for (int i = 0; i < array.Count; i++)
        {
            RefAtom refAtom = array[i] as RefAtom;
            if ((refAtom != null) && (refAtom.ID == id))
            {
                ArrayRemoveAt(array, i);
                return true;
            }
        }
    }
    return false;
}

private static void ArrayRemoveAt(ArrayAtom array, int index)
{
    if (index == 0)
    { // Workaround for bug in some versions of ABCpdf
        Atom[] copy = new Atom[array.Count];
        array.CopyTo(copy, 0);
        array.Clear();
        for (int i = 1; i < copy.Length; i++)
            array.Add(copy[i]);
    }
    else
    {
        array.RemoveAt(index);
    }
}

How to add a TextField if there is already an existing TextField in ABCPDF?

1 Answers1