PDFlib 8 Windows COM/.NET Tutorial

egin_pattern( ), shading_pattern( ), shading( ): patterns and shadings must be defined
outside the template, but can be used within the template.
> begin_item( ) and tag option of various functions: structure elements cannot be created
within a template.
> All interactive functions, since these must always be defined on the page where they
should appear in the document, and cannot be generated as part of a template.
Cookbook A full code sample can be found in the Cookbook topic general/repeated_contents.
3.2.5 Referenced Pages from an external PDF Document
Cookbook A full code sample can be found in the Cookbook topic pdfx/starter_pdfx5g.
PDF documents can contain references to pages in external documents: the (scaled or
rotated) reference page is not part of the document, it will be displayed and printed just
like other page content. This can be used to reference re-used graphical contents (e.g.
logos or cover pages) without including the corresponding PDF data. PDFlib supports
strong references, i.e. references where the referenced page is identified via internal
metadata. If the referenced page is not available or does not match the expected metadata,
a proxy image will be displayed instead of the referenced page.
Using referenced pages in Acrobat. Although referenced pages (the technical term is
Reference XObjects) have already been specified in PDF 1.4 (i.e. the file format of
Acrobat 5), they require Acrobat 9 or above for proper display and printing. Referenced
pages are a crucial component of PDF/X-5g and PDF/X-5pg. The generated (new) document
is called the container document; the external PDF document with the referenced
page is called the target file.
In order to use referenced pages with Acrobat 9 or X it is important to properly configure
Acrobat as follows:
> Edit, Preferences, General..., Page Display, Show reference XObject targets: set to Always
(the setting Only PDF-X/5 compliant ones doesn’t work due to a bug in Acrobat).
> Edit, Preferences, General..., Page Display, Location of referenced files: enter the name of
the directory where the target files live.
> Edit, Preferences, General..., Security (Enhanced), Privileged Locations, Add Folder Path: add
the name of the directory where the container documents live. This must be done regardless
of the Enable Enhanced Security setting.
The target page, whose file name and page number are specified inside the container
PDF, will be displayed instead of the proxy if all of the following conditions are true:
> The container document is trusted according to Acrobat’s configuration;
> The target file can be found in the specified directory;
> The target file does not require any password and can be opened without errors.
> The page number of the referenced page specified in the container document exists
in the target file.
> PDF/X-5 only: the ID and certain XMP metadata entries in the target must match the
corresponding entries in the container document.
If one or more of these conditions are violated, the proxy will silently be displayed instead
of the target page. Acrobat will not issue any error message.
74 Chapter 3: Creating PDF Documents (Edition for COM, .NET, and REALbasic)