/// <summary>
/// Gets the resource name of the specified form within this dictionary.
/// </summary>
internal string GetFormName(XForm form)
{
PDFFormXObject pdfForm = _document.ExternalDocumentTable.GetForm(form);
Debug.Assert(pdfForm != null);
string name = Resources.AddForm(pdfForm);
return(name);
}
/// <summary>
/// Initializes a new instance of this class with the document the objects are imported from.
/// </summary>
public PDFImportedObjectTable(PDFDocument owner, PDFDocument externalDocument)
{
if (externalDocument == null)
{
throw new ArgumentNullException("externalDocument");
}
Owner = owner ?? throw new ArgumentNullException("owner");
_externalDocumentHandle = externalDocument.Handle;
_xObjects = new PDFFormXObject[externalDocument.PageCount];
}
/// <summary>
/// Adds the specified form object to this resource dictionary
/// and returns its local resource name.
/// </summary>
public string AddForm(PDFFormXObject form)
{
if (!_resources.TryGetValue(form, out string name))
{
name = NextFormName;
_resources[form] = name;
if (form.Reference == null)
{
Owner.IrefTable.Add(form);
}
XObjects.Elements[name] = form.Reference;
}
return(name);
}
/// <summary>
/// Gets a PDFFormXObject from an XPDFForm. Because the returned objects must be unique, always
/// a new instance of PDFFormXObject is created if none exists for the specified form.
/// </summary>
public PDFFormXObject GetForm(XForm form)
{
// If the form already has a PDFFormXObject, return it.
if (form._pdfForm != null)
{
Debug.Assert(form.IsTemplate, "An XPDFForm must not have a PDFFormXObject.");
if (ReferenceEquals(form._pdfForm.Owner, Owner))
{
return(form._pdfForm);
}
//throw new InvalidOperationException("Because of a current limitation of PDFSharp an XPDFForm object can be used only within one single PDFDocument.");
// Dispose PDFFromXObject when document has changed
form._pdfForm = null;
}
if (form is XPDFForm pdfForm)
{
// Is the external PDF file from which is imported already known for the current document?
Selector selector = new Selector(form);
if (!_forms.TryGetValue(selector, out PDFImportedObjectTable importedObjectTable))
{
// No: Get the external document from the form and create ImportedObjectTable.
PDFDocument doc = pdfForm.ExternalDocument;
importedObjectTable = new PDFImportedObjectTable(Owner, doc);
_forms[selector] = importedObjectTable;
}
PDFFormXObject xObject = importedObjectTable.GetXObject(pdfForm.PageNumber);
if (xObject == null)
{
xObject = new PDFFormXObject(Owner, importedObjectTable, pdfForm);
importedObjectTable.SetXObject(pdfForm.PageNumber, xObject);
}
return(xObject);
}
Debug.Assert(form.GetType() == typeof(XForm));
form._pdfForm = new PDFFormXObject(Owner, form);
return(form._pdfForm);
}
public void SetXObject(int pageNumber, PDFFormXObject xObject) => _xObjects[pageNumber - 1] = xObject;
