When generating appearance streams for variable text annotations,
properly handle the cases of there being no appearance dictionary, no
appearance stream, or an appearance stream with no BMC..EMC marker.
With the exception of form field annotations when /NeedAppearances is
true, remove annotations that don't have appearance streams when
flattening. There is no reason to keep these when flattening since
they are invisible. This may include unchecked checkboxes, unshown
popup windows, etc.
Allow fine control over how passwords are encoded for writing, and
allow password for reading to be given as a hexademical encoded
string. Allow suppression of password recovery as a means to ensure
that the password you specify is actually the right one.
Setting encryption permissions for R >= 3 set permission bits in
groups corresponding to menu options in Acrobat 5. The new API allows
the bits to be set individually.
Explicitly abandon removal of unreferenced resources if there are any
lexical errors in the page's contents. This case always generated a
warning, but it now also prevents removal of unreferenced resources,
this strongly decreasing the likelihood of data loss.
The original QPDF is only required now when the source
QPDFObjectHandle is a stream that gets its stream data from a
QPDFObjectHandle::StreamDataProvider.
Some of the images were supposed to have no filter, but somewhere
along the line, they ended up with /FlateDecode, most likely because
qpdf rewrote the file without having --compress-streams=n specified.
If this error is repeated, it will cause a test failure.
On certain operations, such as iterating through all objects and
adding new indirect objects, walk through the entire object structure
and explicitly resolve any indirect references to non-existent
objects. That prevents new objects from springing into existence and
causing the previously dangling references to point to them.
Instead of directly putting the contents of the annotation appearance
streams into the page's content stream, add commands to render the
form xobjects directly. This is a more robust way to do it than the
original solution as it works properly with patterns and avoids
problems with resource name clashes between the pages and the form
xobjects.
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.
Unparse is admittedly strange, but I'd rather be strange and
consistent, and everything else in the qpdf library uses unparse to
serialize. (If you're reading this, the convention of using "unparse"
comes from the "clu" programming language.)
