Annotation flattening including form fields

Flatten annotations by integrating their appearance streams into the
content stream of the containing page. In the case of form fields,
only flatten if /NeedAppearance is false (or equivalently absent). If
flattening form fields, also remove /AcroForm from the document
catalog.

1 files changed, 127 insertions, 0 deletions

diff --git a/libqpdf/QPDFPageDocumentHelper.cc b/libqpdf/QPDFPageDocumentHelper.cc
index f4774896..4d117017 100644
--- a/libqpdf/QPDFPageDocumentHelper.cc
+++ b/libqpdf/QPDFPageDocumentHelper.cc
@@ -1,4 +1,6 @@
 #include <qpdf/QPDFPageDocumentHelper.hh>
+#include <qpdf/QPDFAcroFormDocumentHelper.hh>
+#include <qpdf/QTC.hh>
 
 QPDFPageDocumentHelper::Members::~Members()
 {
@@ -62,3 +64,128 @@ QPDFPageDocumentHelper::removePage(QPDFPageObjectHelper page)
 {
     this->qpdf.removePage(page.getObjectHandle());
 }
+
+
+void
+QPDFPageDocumentHelper::flattenAnnotations()
+{
+    QPDFAcroFormDocumentHelper afdh(this->qpdf);
+    if (afdh.getNeedAppearances())
+    {
+        this->qpdf.getRoot().getKey("/AcroForm").warnIfPossible(
+            "document does not have updated appearance streams,"
+            " so form fields will not be flattened");
+    }
+    pushInheritedAttributesToPage();
+    std::vector<QPDFPageObjectHelper> pages = getAllPages();
+    for (std::vector<QPDFPageObjectHelper>::iterator iter = pages.begin();
+         iter != pages.end(); ++iter)
+    {
+        QPDFPageObjectHelper ph(*iter);
+        QPDFObjectHandle page_oh = ph.getObjectHandle();
+        if (page_oh.getKey("/Resources").isIndirect())
+        {
+            QTC::TC("qpdf", "QPDFPageDocumentHelper indirect resources");
+            page_oh.replaceKey("/Resources",
+                               page_oh.getKey("/Resources").shallowCopy());
+        }
+        QPDFObjectHandle resources = ph.getObjectHandle().getKey("/Resources");
+        if (! resources.isDictionary())
+        {
+            // This should never happen and is not exercised in the
+            // test suite
+            resources = QPDFObjectHandle::newDictionary();
+        }
+        flattenAnnotationsForPage(ph, resources, afdh);
+    }
+    if (! afdh.getNeedAppearances())
+    {
+        this->qpdf.getRoot().removeKey("/AcroForm");
+    }
+}
+
+void
+QPDFPageDocumentHelper::flattenAnnotationsForPage(
+    QPDFPageObjectHelper& page,
+    QPDFObjectHandle& resources,
+    QPDFAcroFormDocumentHelper& afdh)
+{
+    bool need_appearances = afdh.getNeedAppearances();
+    std::vector<QPDFAnnotationObjectHelper> annots = page.getAnnotations();
+    std::vector<QPDFObjectHandle> new_annots;
+    std::string new_content;
+    int rotate = 0;
+    QPDFObjectHandle rotate_obj =
+        page.getObjectHandle().getKey("/Rotate");
+    if (rotate_obj.isInteger() && rotate_obj.getIntValue())
+    {
+        rotate = rotate_obj.getIntValue();
+    }
+    for (std::vector<QPDFAnnotationObjectHelper>::iterator iter =
+             annots.begin();
+         iter != annots.end(); ++iter)
+    {
+        QPDFAnnotationObjectHelper& aoh(*iter);
+        QPDFObjectHandle as = aoh.getAppearanceStream("/N");
+        bool is_widget = (aoh.getSubtype() == "/Widget");
+        bool process = true;
+        if (need_appearances && is_widget)
+        {
+            QTC::TC("qpdf", "QPDFPageDocumentHelper skip widget need appearances");
+            process = false;
+        }
+        if (process && (! as.isStream()))
+        {
+            process = false;
+        }
+        if (process)
+        {
+            resources.mergeDictionary(as.getDict().getKey("/Resources"));
+            if (is_widget)
+            {
+                QTC::TC("qpdf", "QPDFPageDocumentHelper merge DR");
+                QPDFFormFieldObjectHelper ff = afdh.getFieldForAnnotation(aoh);
+                resources.mergeDictionary(ff.getInheritableFieldValue("/DR"));
+            }
+            else
+            {
+                QTC::TC("qpdf", "QPDFPageDocumentHelper non-widget annotation");
+            }
+            new_content += aoh.getPageContentForAppearance(rotate);
+        }
+        else
+        {
+            new_annots.push_back(aoh.getObjectHandle());
+        }
+    }
+    if (new_annots.size() != annots.size())
+    {
+        QPDFObjectHandle page_oh = page.getObjectHandle();
+        if (new_annots.empty())
+        {
+            QTC::TC("qpdf", "QPDFPageDocumentHelper remove annots");
+            page_oh.removeKey("/Annots");
+        }
+        else
+        {
+            QPDFObjectHandle old_annots = page_oh.getKey("/Annots");
+            QPDFObjectHandle new_annots_oh =
+                QPDFObjectHandle::newArray(new_annots);
+            if (old_annots.isIndirect())
+            {
+                QTC::TC("qpdf", "QPDFPageDocumentHelper replace indirect annots");
+                this->qpdf.replaceObject(
+                    old_annots.getObjGen(), new_annots_oh);
+            }
+            else
+            {
+                QTC::TC("qpdf", "QPDFPageDocumentHelper replace direct annots");
+                page_oh.replaceKey("/Annots", new_annots_oh);
+            }
+        }
+        page.addPageContents(
+            QPDFObjectHandle::newStream(&qpdf, "q\n"), true);
+        page.addPageContents(
+            QPDFObjectHandle::newStream(&qpdf, "\nQ\n" + new_content), false);
+    }
+}