> Am 12.10.2021 um 13:15 schrieb Hans Hagen <j.ha...@xs4all.nl>:
>
> On 10/12/2021 12:36 PM, Henning Hraban Ramm via ntg-context wrote:
>> Comrades!
>> There must have been a time when PDF boxes (i.e. CropBox, TrimBox, BleedBox)
>> worked as they should, but it must have been a short time.
>
> I long ago lost track of what all that means ... decades of pdf ... different
> viewers, different interpretations ... validators complaining about things
> missing ... i guess that bit (like annotations) will always be in flux (also
> because specs came before implementations i guess).
Hm, you implemented these boxes only in 2015, there was not much change in that
regard since then.
>> * BleedBox must be TrimBox plus bleed.
>
> a relative new one, probably also sensitive for interpretation by renderer,
> imo worthless
Not worthless; workflow systems in printshops rely on BleedBox and TrimBox.
It’s not about rendering, but imposition and even postprocessing (cutting etc.).
>> * ArtBox is neglectable for whole layouts (same as TrimBox might make
>> sense), just interesting in \externalfigure.
>
> also worthless
I agree.
>> With
>> \setuppaper[A4][A4,oversized]
>> I’d expect ConTeXt to set...
>> * MediaBox and CropBox to the bigger format
>> * TrimBox to the page format (A4)
>> * BleedBox also to the page format, while no bleed is defined
>
> well, that's an assumption ... who knows what a printer (driver) does ...
Who sends PDF files directly to a printer (driver)? I know it only from
automated, professional workflows.
Usually printer drivers gets fed by PDF viewers, and I know none that even
*can* print something different than CropBox.
>> Beware, \setupbleeding refers only to stretching of images (\externalfigure)!
>
> fwiw, that bleeding options is mostly there to communicate with mp
Good to know. I just browsed the Details manual, didn’t try it yet, since I
scale and move my “bleeding” images differently.
>> * to define trimoffset, I must know the difference between paper size and
>> sheet size ("oversized" adds 15 mm).
>
> oversized is a convenience feature, in prepress one would define a real,
> target size, not rely on a convenience value
But it’s convenient ;) I usually just need a format that is big enough for the
crop marks, and “oversized” does that.
>> % ... and no dependency on interactionscreen!
>
> that's a historic fact ... special pdf features triggered by that command ..
> basically tex only has a page size
Of course, but it doesn’t make sense any more, and defining the boxes wouldn’t
hurt anyone. (I’m quite sure, but let them beat me ;))
>> Yes, that would mean a backward incompatible change. But how many of us rely
>> on the strange current behavior?
>> Please let us fix this!
>
> the problem is as usual documentation and indeed we can have some backward
> compatibility issue here ... i honestly have no clue how viewers and printers
> react (so if something would be added/changed it would be option driven)
I wouldn’t expect printers (office printing devices) to react at all; I hope
that printers (printshop workers) will react positively to correct boxes in our
PDFs ;)
>> In some cases it makes sense to have different values on e.g. inner and
>> outer edges; I feat that would add a plethora of additional parameters
>> (leftbleedoffset, innerbleedoffset...).
>> Maybe give a list like in CSS? bleedoffset={3mm,3mm,3mm,0mm} – top, right,
>> bottom, left order implied; not very “ConTeXt style”.
> probably spreads need some treatment (imposition)
Multiple pages on a sheet are not considered by the PDF specs.
> (i'm pretty sure that changes will themselves introduce new issues)
Probable.
> anyway, we can look at it once we're all on lmtx because i'm not going to
> change mkiv in that aspect
Ok
Hraban
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