Changelog:
8.1.0: June 23, 2018
Usability Improvements
When splitting files, qpdf detects fonts and images that the document metadata claims are referenced from a page but are not actually referenced and omits them from the output file. This change can cause a significant reduction in the size of split PDF files for files created by some software packages. Prior versions of qpdf would believe the document metadata and sometimes include all the images from all the other pages even though the pages were no longer present. In the unlikely event that the old behavior should be desired, it can be enabled by specifying --preserve-unreferenced-resources. For additional details, please see Section 3.6, “Advanced Transformation Options”.
When merging multiple PDF files, qpdf no longer leaves all the files open. This makes it possible to merge numbers of files that may exceed the operating system's limit for the maximum number of open files.
The --rotate option's syntax has been extended to make the page range optional. If you specify --rotate=angle without specifying a page range, the rotation will be applied to all pages. This can be especially useful for adjusting a PDF created from a multi-page document that was scanned upside down.
When merging multiple files, the --verbose option now prints information about each file as it operates on that file.
When the --progress option is specified, qpdf will print a running indicator of its best guess at how far through the writing process it is. Note that, as with all progress meters, it's an approximation. This option is implemented in a way that makes it useful for software that uses the qpdf library; see API Enhancements below.
Bug Fixes
Properly decrypt files that use revision 3 of the standard security handler but use 40 bit keys (even though revision 3 supports 128-bit keys).
Limit depth of nested data structures to prevent crashes from certain types of malformed (malicious) PDFs.
In “newline before endstream” mode, insert the required extra newline before the endstream at the end of object streams. This one case was previously omitted.
API Enhancements
The first round of higher level “helper” interfaces has been introduced. These are designed to provide a more convenient way of interacting with certain document features than using QPDFObjectHandle directly. For details on helpers, see Section 6.3, “Helper Classes”. Specific additional interfaces are described below.
Add two new document helper classes: QPDFPageDocumentHelper for working with pages, and QPDFAcroFormDocumentHelper for working with interactive forms. No old methods have been removed, but QPDFPageDocumentHelper is now the preferred way to perform operations on pages rather than calling the old methods in QPDFObjectHandle and QPDF directly. Comments in the header files direct you to the new interfaces. Please see the header files and ChangeLog for additional details.
Add three new object helper class: QPDFPageObjectHelper for pages, QPDFFormFieldObjectHelper for interactive form fields, and QPDFAnnotationObjectHelper for annotations. All three classes are fairly sparse at the moment, but they have some useful, basic functionality.
A new example program examples/pdf-set-form-values.cc has been added that illustrates use of the new document and object helpers.
The method QPDFWriter::registerProgressReporter has been added. This method allows you to register a function that is called by QPDFWriter to update your idea of the percentage it thinks it is through writing its output. Client programs can use this to implement reasonably accurate progress meters. The qpdf command line tool uses this to implement its --progress option.
New methods QPDFObjectHandle::newUnicodeString and QPDFObject::unparseBinary have been added to allow for more convenient creation of strings that are explicitly encoded using big-endian UTF-16. This is useful for creating strings that appear outside of content streams, such as labels, form fields, outlines, document metadata, etc.
A new class QPDFObjectHandle::Rectangle has been added to ease working with PDF rectangles, which are just arrays of four numeric values.
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