PDFHummus::EStatusCode PDFModifiedPage::WritePage()
{
EStatusCode status = EndContentContext(); // just in case someone forgot to close the latest content context
do {
if (status != eSuccess || !mIsDirty) {
break;
}
// allocate an object ID for the new contents stream (for placing the form)
// we first create the modified page object, so that we can define a name for the new form xobject
// that is unique
ObjectsContext& objectContext = mWriter->GetObjectsContext();
ObjectIDType newContentObjectID = objectContext.GetInDirectObjectsRegistry().AllocateNewObjectID();
ObjectIDType newEncapsulatingObjectID = 0;
// create a copying context, so we can copy the page dictionary, and modify its contents + resources dict
PDFDocumentCopyingContext* copyingContext = mWriter->CreatePDFCopyingContextForModifiedFile();
// get the page object
ObjectIDType pageObjectID = copyingContext->GetSourceDocumentParser()->GetPageObjectID(mPageIndex);
PDFObjectCastPtr<PDFDictionary> pageDictionaryObject = copyingContext->GetSourceDocumentParser()->ParsePage(mPageIndex);
MapIterator<PDFNameToPDFObjectMap> pageDictionaryObjectIt = pageDictionaryObject->GetIterator();
// create modified page object
objectContext.StartModifiedIndirectObject(pageObjectID);
DictionaryContext* modifiedPageObject = mWriter->GetObjectsContext().StartDictionary();
// copy all elements of the page to the new page object, but the "Contents", "Resources" and "Annots" elements
while (pageDictionaryObjectIt.MoveNext())
{
if (pageDictionaryObjectIt.GetKey()->GetValue() != "Resources" &&
pageDictionaryObjectIt.GetKey()->GetValue() != "Contents" &&
pageDictionaryObjectIt.GetKey()->GetValue() != "Annots")
{
modifiedPageObject->WriteKey(pageDictionaryObjectIt.GetKey()->GetValue());
copyingContext->CopyDirectObjectAsIs(pageDictionaryObjectIt.GetValue());
}
}
// Write new annotations entry, joining existing annotations, and new ones (from links attaching or what not)
if (pageDictionaryObject->Exists("Annots") || mWriter->GetDocumentContext().GetAnnotations().size() > 0)
{
modifiedPageObject->WriteKey("Annots");
objectContext.StartArray();
// write old annots, if any exist
if(pageDictionaryObject->Exists("Annots")) {
PDFObjectCastPtr<PDFArray> anArray(copyingContext->GetSourceDocumentParser()->QueryDictionaryObject(pageDictionaryObject.GetPtr(), "Annots"));
SingleValueContainerIterator<PDFObjectVector> refs = anArray->GetIterator();
while (refs.MoveNext())
copyingContext->CopyDirectObjectAsIs(refs.GetItem());
}
// write new annots from links
ObjectIDTypeSet& annotations = mWriter->GetDocumentContext().GetAnnotations();
if (annotations.size() > 0)
{
ObjectIDTypeSet::iterator it = annotations.begin();
for (; it != annotations.end(); ++it)
objectContext.WriteNewIndirectObjectReference(*it);
}
annotations.clear();
objectContext.EndArray(eTokenSeparatorEndLine);
}
// Write new contents entry, joining the existing contents with the new one. take care of various scenarios of the existing Contents
modifiedPageObject->WriteKey("Contents");
if (!pageDictionaryObject->Exists("Contents"))
{ // no contents
objectContext.WriteIndirectObjectReference(newContentObjectID);
}
else
{
objectContext.StartArray();
if (mEnsureContentEncapsulation)
{
newEncapsulatingObjectID = objectContext.GetInDirectObjectsRegistry().AllocateNewObjectID();
objectContext.WriteNewIndirectObjectReference(newEncapsulatingObjectID);
}
RefCountPtr<PDFObject> pageContent(copyingContext->GetSourceDocumentParser()->QueryDictionaryObject(pageDictionaryObject.GetPtr(), "Contents"));
if (pageContent->GetType() == PDFObject::ePDFObjectStream)
{
// single content stream. must be a refrence which points to it
PDFObjectCastPtr<PDFIndirectObjectReference> ref(pageDictionaryObject->QueryDirectObject("Contents"));
objectContext.WriteIndirectObjectReference(ref->mObjectID, ref->mVersion);
}
else if (pageContent->GetType() == PDFObject::ePDFObjectArray)
{
PDFArray* anArray = (PDFArray*)pageContent.GetPtr();
// multiple content streams
SingleValueContainerIterator<PDFObjectVector> refs = anArray->GetIterator();
PDFObjectCastPtr<PDFIndirectObjectReference> ref;
while (refs.MoveNext())
{
ref = refs.GetItem();
objectContext.WriteIndirectObjectReference(ref->mObjectID, ref->mVersion);
}
}
else {
// this basically means no content...or whatever. just ignore.
}
objectContext.WriteNewIndirectObjectReference(newContentObjectID);
objectContext.EndArray();
objectContext.EndLine();
}
// Write a new resource entry. copy all but the "XObject" entry, which needs to be modified. Just for kicks i'm keeping the original
// form (either direct dictionary, or indirect object)
ObjectIDType resourcesIndirect = 0;
ObjectIDType newResourcesIndirect = 0;
vector<string> formResourcesNames;
modifiedPageObject->WriteKey("Resources");
if (!pageDictionaryObject->Exists("Resources"))
{
// check if there's inherited dict. if so - write directly as a modified version
PDFObjectCastPtr<PDFDictionary> parentDict(
pageDictionaryObject->Exists("Parent") ?
copyingContext->GetSourceDocumentParser()->QueryDictionaryObject(pageDictionaryObject.GetPtr(), "Parent"):
NULL);
if(!parentDict) {
formResourcesNames = WriteNewResourcesDictionary(objectContext);
}
else {
PDFObjectCastPtr<PDFDictionary> inheritedResources = findInheritedResources(copyingContext->GetSourceDocumentParser(),parentDict.GetPtr());
if(!inheritedResources) {
formResourcesNames = WriteNewResourcesDictionary(objectContext);
} else {
formResourcesNames = WriteModifiedResourcesDict(copyingContext->GetSourceDocumentParser(), inheritedResources.GetPtr(), objectContext, copyingContext);
}
}
}
else
{
// resources may be direct, or indirect. if direct, write as is, adding the new form xobject, otherwise wait till page object ends and write then
PDFObjectCastPtr<PDFIndirectObjectReference> resourceDictRef(pageDictionaryObject->QueryDirectObject("Resources"));
if (!resourceDictRef)
{
PDFObjectCastPtr<PDFDictionary> resourceDict(pageDictionaryObject->QueryDirectObject("Resources"));
formResourcesNames = WriteModifiedResourcesDict(copyingContext->GetSourceDocumentParser(), resourceDict.GetPtr(), objectContext, copyingContext);
}
else
{
resourcesIndirect = resourceDictRef->mObjectID;
// later will write a modified version of the resources dictionary, with the new form.
// only modify the resources dict object if wasn't already modified (can happen when sharing resources dict between multiple pages).
// in the case where it was alrady modified, create a new resources dictionary that's a copy, and use it instead, to avoid overwriting
// the previous modification
GetObjectWriteInformationResult res = objectContext.GetInDirectObjectsRegistry().GetObjectWriteInformation(resourcesIndirect);
if (res.first && res.second.mIsDirty)
{
newResourcesIndirect = objectContext.GetInDirectObjectsRegistry().AllocateNewObjectID();
modifiedPageObject->WriteObjectReferenceValue(newResourcesIndirect);
}
else
modifiedPageObject->WriteObjectReferenceValue(resourcesIndirect);
}
}
objectContext.EndDictionary(modifiedPageObject);
objectContext.EndIndirectObject();
if (resourcesIndirect != 0)
{
if (newResourcesIndirect != 0)
objectContext.StartNewIndirectObject(newResourcesIndirect);
else
objectContext.StartModifiedIndirectObject(resourcesIndirect);
PDFObjectCastPtr<PDFDictionary> resourceDict(copyingContext->GetSourceDocumentParser()->ParseNewObject(resourcesIndirect));
formResourcesNames = WriteModifiedResourcesDict(copyingContext->GetSourceDocumentParser(), resourceDict.GetPtr(), objectContext, copyingContext);
objectContext.EndIndirectObject();
}
// if required write encapsulation code, so that new stream is independent of graphic context of original
PDFStream* newStream;
PrimitiveObjectsWriter primitivesWriter;
if (newEncapsulatingObjectID != 0)
{
objectContext.StartNewIndirectObject(newEncapsulatingObjectID);
newStream = objectContext.StartPDFStream();
primitivesWriter.SetStreamForWriting(newStream->GetWriteStream());
primitivesWriter.WriteKeyword("q");
objectContext.EndPDFStream(newStream);
}
// last but not least, create the actual content stream object, placing the form
objectContext.StartNewIndirectObject(newContentObjectID);
newStream = objectContext.StartPDFStream();
primitivesWriter.SetStreamForWriting(newStream->GetWriteStream());
if (newEncapsulatingObjectID != 0) {
primitivesWriter.WriteKeyword("Q");
}
vector<string>::iterator it = formResourcesNames.begin();
for (; it != formResourcesNames.end(); ++it)
{
primitivesWriter.WriteKeyword("q");
primitivesWriter.WriteInteger(1);
primitivesWriter.WriteInteger(0);
primitivesWriter.WriteInteger(0);
primitivesWriter.WriteInteger(1);
primitivesWriter.WriteInteger(0);
primitivesWriter.WriteInteger(0);
primitivesWriter.WriteKeyword("cm");
primitivesWriter.WriteName(*it);
primitivesWriter.WriteKeyword("Do");
primitivesWriter.WriteKeyword("Q");
}
objectContext.EndPDFStream(newStream);
} while (false);
return status;
}
