PDF Boxes

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Revision as of 08:37, 24 August 2015 by Hraban (talk | contribs) (Update about ArtBox)
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< PDF/X | PDF/A >

Basics

While PostScript (and EPS, that is) knows only one kind of page size, defined by the BoundingBox (or HiResBoundingBox), the size of PDF pages can have different meanings – e.g. the visible page, the printed page, the cropped printed page. Therefore the PDF standard defines a set of "boxes":

Name Meaning
CropBox Page size that is visible in a viewer (fallback for the other boxes, minimally required)
BleedBox Page size plus bleed (cut space)
TrimBox Size of trimmed (cut) page, "final" page size
MediaBox Size of the physical medium (print sheet)
ArtBox Size of the page content (artwork); might be used for imposition purposes

In PDF/X, if ArtBox is defined at all, it must not differ from TrimBox.

In ConTeXt

End of August 2015 ConTeXt got the necessary setup keys to define these boxes (minimal example by Hans):

\showframe

\setuplayout
 [location=middle,
  width=middle,
  height=middle,
  cropoffset=auto,
  trimoffset=1bp,
  bleedoffset=2bp
]

\starttext

\definepapersize[TestA][width=100bp,height=200bp]
\definepapersize[TestB][width=150bp,height=250bp]

\setuppapersize[TestA][TestB]

test

\stoptext

The auto option only works with layout=middle (message otherwise). The offset are accumulative (so crop < trim < bleed).

The default CropBox and TrimBox handling is unchanged, so one really needs to set this when it's needed. The already present interactionscreen cropping is unchanged.

ConTeXt doesn’t set ArtBox at the moment, since nobody seems to need it.