Removes all Form
XObjects from the page by embedding them into the content.
Most Form XObjects can be embedded in the page with no
difference in page appearance. However Form XObjects such as
transparency groups contain structures which cannot be represented
any other way. These structures are uncommon in most documents but
they do occur.
In this situation you need to decide whether a change in page
appearance is acceptable and that the objects should be forcibly
embedded. The alternative is to skip these objects and embed only
those that will not affect the page appearance.
The levels parameter allows you to determine the level of
nesting which should be removed. The number refers to the maximum
number of iterations that should be performed. At each iteration
the Form XObjects referenced by the page are flattened into the
page. However if those Form XObjects themselves reference other
Form XObjects then those will then become page level Form XObjects.
Hence there can be a number of rounds of flattening. By default the
sequence is repeated until there are no Form XObjects left. However
sometimes it can be useful to be more selective and this can be
controlled using this parameter.