qpdf/examples/pdf-overlay-page.cc

111 lines
3.3 KiB
C++

#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <qpdf/QPDF.hh>
#include <qpdf/QPDFPageDocumentHelper.hh>
#include <qpdf/QPDFPageObjectHelper.hh>
#include <qpdf/QPDFWriter.hh>
#include <qpdf/QUtil.hh>
// This program demonstrates use of form XObjects to overlay a page
// from one file onto all pages of another file. The qpdf program's
// --overlay and --underlay options provide a more general version of
// this capability.
static char const* whoami = 0;
void usage()
{
std::cerr << "Usage: " << whoami << " infile pagefile outfile"
<< std::endl
<< "Stamp page 1 of pagefile on every page of infile,"
<< " writing to outfile"
<< std::endl;
exit(2);
}
static void stamp_page(char const* infile,
char const* stampfile,
char const* outfile)
{
QPDF inpdf;
inpdf.processFile(infile);
QPDF stamppdf;
stamppdf.processFile(stampfile);
// Get first page from other file
QPDFPageObjectHelper stamp_page_1 =
QPDFPageDocumentHelper(stamppdf).getAllPages().at(0);
// Convert page to a form XObject
QPDFObjectHandle foreign_fo = stamp_page_1.getFormXObjectForPage();
// Copy form XObject to the input file
QPDFObjectHandle stamp_fo = inpdf.copyForeignObject(foreign_fo);
// For each page...
std::vector<QPDFPageObjectHelper> pages =
QPDFPageDocumentHelper(inpdf).getAllPages();
for (std::vector<QPDFPageObjectHelper>::iterator iter = pages.begin();
iter != pages.end(); ++iter)
{
QPDFPageObjectHelper& ph = *iter;
// Find a unique resource name for the new form XObject
QPDFObjectHandle resources = ph.getAttribute("/Resources", true);
int min_suffix = 1;
std::string name = resources.getUniqueResourceName("/Fx", min_suffix);
// Generate content to place the form XObject centered within
// destination page's trim box.
std::string content =
ph.placeFormXObject(
stamp_fo, name, ph.getTrimBox().getArrayAsRectangle());
if (! content.empty())
{
// Append the content to the page's content. Surround the
// original content with q...Q to the new content from the
// page's original content.
resources.mergeResources(
QPDFObjectHandle::parse("<< /XObject << >> >>"));
resources.getKey("/XObject").replaceKey(name, stamp_fo);
ph.addPageContents(
QPDFObjectHandle::newStream(&inpdf, "q\n"), true);
ph.addPageContents(
QPDFObjectHandle::newStream(&inpdf, "\nQ\n" + content), false);
}
}
QPDFWriter w(inpdf, outfile);
w.setStaticID(true); // for testing only
w.write();
}
int main(int argc, char* argv[])
{
whoami = QUtil::getWhoami(argv[0]);
// For libtool's sake....
if (strncmp(whoami, "lt-", 3) == 0)
{
whoami += 3;
}
if (argc != 4)
{
usage();
}
char const* infile = argv[1];
char const* stampfile = argv[2];
char const* outfile = argv[3];
try
{
stamp_page(infile, stampfile, outfile);
}
catch (std::exception &e)
{
std::cerr << whoami << ": " << e.what() << std::endl;
exit(2);
}
return 0;
}