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qpdf/examples/pdf-double-page-size.cc
2023-06-02 16:00:40 +01:00

98 lines
2.9 KiB
C++

#include <qpdf/Buffer.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/QPDFPageDocumentHelper.hh>
#include <qpdf/QPDFPageObjectHelper.hh>
#include <qpdf/QPDFWriter.hh>
#include <qpdf/QUtil.hh>
#include <cstdlib>
#include <cstring>
#include <iostream>
static char const* whoami = nullptr;
void
usage()
{
std::cerr << "Usage: " << whoami << " infile.pdf outfile.pdf [in-password]" << std::endl
<< "Double size of all pages in infile.pdf; write output to outfile.pdf" << std::endl;
exit(2);
}
// If there is a box of name box_name, replace it with a new box whose elements are double the
// values of the original box.
static void
doubleBoxSize(QPDFPageObjectHelper& page, char const* box_name)
{
// We need to use getAttribute rather than getKey as some boxes could be inherited.
auto box = page.getAttribute(box_name, true);
if (box.isNull()) {
return;
}
if (!box.isRectangle()) {
throw std::runtime_error(
std::string("box ") + box_name + " is not an array of four elements");
}
std::vector<QPDFObjectHandle> doubled;
for (auto& item: box.aitems()) {
doubled.push_back(QPDFObjectHandle::newReal(item.getNumericValue() * 2.0, 2));
}
page.getObjectHandle().replaceKey(box_name, QPDFObjectHandle::newArray(doubled));
}
int
main(int argc, char* argv[])
{
whoami = QUtil::getWhoami(argv[0]);
// For test suite
bool static_id = false;
if ((argc > 1) && (strcmp(argv[1], " --static-id") == 0)) {
static_id = true;
--argc;
++argv;
}
if (!((argc == 3) || (argc == 4))) {
usage();
}
char const* infilename = argv[1];
char const* outfilename = argv[2];
char const* password = (argc == 4) ? argv[3] : "";
// Text to prepend to each page's contents
std::string content = "2 0 0 2 0 0 cm\n";
try {
QPDF qpdf;
qpdf.processFile(infilename, password);
for (auto& page: QPDFPageDocumentHelper(qpdf).getAllPages()) {
// Prepend the buffer to the page's contents
page.addPageContents(qpdf.newStream(content), true);
// Double the size of each of the content boxes
doubleBoxSize(page, "/MediaBox");
doubleBoxSize(page, "/CropBox");
doubleBoxSize(page, "/BleedBox");
doubleBoxSize(page, "/TrimBox");
doubleBoxSize(page, "/ArtBox");
}
// Write out a new file
QPDFWriter w(qpdf, outfilename);
if (static_id) {
// For the test suite, uncompress streams and use static IDs.
w.setStaticID(true); // for testing only
w.setStreamDataMode(qpdf_s_uncompress);
}
w.write();
std::cout << whoami << ": new file written to " << outfilename << std::endl;
} catch (std::exception& e) {
std::cerr << whoami << " processing file " << infilename << ": " << e.what() << std::endl;
exit(2);
}
return 0;
}