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":
|ArtBox||Size of the page content (artwork); might be used for imposition purposes|
|BleedBox||Page size plus bleed (cut space)|
|CropBox||Page size that is visible in a viewer (fallback for the other boxes)|
|TrimBox||Size of trimmed (cut) page, "final" page size|
|MediaBox||Size of the physical medium (print sheet)|
In PDF/X, if ArtBox is defined at all, it must not differ from TrimBox.
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, artoffset=2bp % makes no sense ] \starttext \definepapersize[TestA][width=100bp,height=200bp] \definepapersize[TestB][width=150bp,height=250bp] \setuppapersize[TestA][TestB] test \stoptext
auto option only works with
layout=middle (message otherwise).
The offset are accumulative (so crop < trim < bleed < art).
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.