Re: [Groff] PDFPIC macro

[Deri James]

On Sun 08 Oct 2017 20:26:02 Keith Marshall wrote:
> You may recall that I did begin to explore possibilities, at the time, 
> but then life ... explicitly a protracted visit to Australia and New 
> Zealand, followed by too many other priorities on return ... got in the 
> way.  I've now found a bit of time to revisit it, and have posted some 
> prototypical code at https://osdn.net/users/keith/pf/groff-psbb/files

Some pdfs I have tried fail with "syntax error". It seems to occur if MediaBox 
is defined in an ancestor 
object rather than in a "/Page object. There are a number of page attributes 
which are inheritable in this 
way, MediaBox is one of them. The standard says:-

============================================================
==================

Inheritance of Page Attributes

Some of the page attributes shown in Table 3.18 are designated as inheritable. 
If such an attribute is 
omitted from a page object, its value is inherited from an ancestor node in the 
page tree. If the attribute is 
a required one, a value must be supplied in an ancestor node; if it is optional 
and no inherited value is 
specified, the default value is used.

An attribute can thus be defined once for a whole set of pages, by specifying 
it in an intermediate page tree 
node and arranging the pages that share the attribute as descendants of that 
node. For example, a 
document might specify the same media box for all of its pages by including a 
MediaBox entry in the root 
node of the page tree. If necessary, an individual page object could then 
override this inherited value with a 
MediaBox entry of its own.

============================================================
==================

So in case a MediaBox is superseded by an entry further down the tree you still 
have to continue looking till 
you get to the object for page 1, to make sure.