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qpdf/examples/pdf-set-form-values.cc
2023-06-02 19:24:12 +01:00

77 lines
2.9 KiB
C++

#include <qpdf/QPDF.hh>
#include <qpdf/QPDFAcroFormDocumentHelper.hh>
#include <qpdf/QPDFPageDocumentHelper.hh>
#include <qpdf/QPDFWriter.hh>
#include <qpdf/QUtil.hh>
#include <cstdlib>
#include <iostream>
static char const* whoami = nullptr;
void
usage()
{
std::cerr << "Usage: " << whoami << " infile.pdf outfile.pdf value" << std::endl
<< "Set the value of all text fields to a specified value" << std::endl;
exit(2);
}
int
main(int argc, char* argv[])
{
whoami = QUtil::getWhoami(argv[0]);
if (argc != 4) {
usage();
}
char const* infilename = argv[1];
char const* outfilename = argv[2];
char const* value = argv[3];
// This is a contrived example that just goes through a file page by page and sets the value of
// any text fields it finds to a fixed value as given on the command line. The purpose here is
// to illustrate use of the helper classes around interactive forms.
try {
QPDF qpdf;
qpdf.processFile(infilename);
// We will iterate through form fields by starting at the page level and looking at each
// field for each page. We could also call QPDFAcroFormDocumentHelper::getFormFields to
// iterate at the field level, but doing it as below illustrates how we can map from
// annotations to fields.
QPDFAcroFormDocumentHelper afdh(qpdf);
for (auto const& page: QPDFPageDocumentHelper(qpdf).getAllPages()) {
// Get all widget annotations for each page. Widget annotations are the ones that
// contain the details of what's in a form field.
for (auto& annot: afdh.getWidgetAnnotationsForPage(page)) {
// For each annotation, find its associated field. If it's a text field, set its
// value.
QPDFFormFieldObjectHelper ffh = afdh.getFieldForAnnotation(annot);
if (ffh.getFieldType() == "/Tx") {
// Set the value. Passing false as the second parameter prevents qpdf from
// setting /NeedAppearances to true (but will not turn it off if it's already
// on), so we call generateAppearance after setting the value. You may or may
// not want to do this depending on whether the appearance streams generated by
// qpdf are good enough for your purposes. For additional details, please see
// comments in QPDFFormFieldObjectHelper.hh for this method.
ffh.setV(value, false);
ffh.generateAppearance(annot);
}
}
}
// Write out a new file
QPDFWriter w(qpdf, outfilename);
w.setStaticID(true); // for testing only
w.write();
} catch (std::exception& e) {
std::cerr << whoami << " processing file " << infilename << ": " << e.what() << std::endl;
exit(2);
}
return 0;
}