Re: Trimbox and crop marks on cover page

I managed to get the desired result by placing the \startMPpage inside a
layer and shifting the layer:

\setlayer[foo][x=-19.5mm,y=-40.5mm]{...}

However, these offsets were found by trial and error.

Setting

\definelayer
  [foo]
  [width=\paperwidth,
   height=\paperheight]

or using the layer as a page background makes no difference.

What is the relation between the origin of a layer and the origin of Page
inside \startMPpage? Is there a documented way to compute these offsets
instead of hard-coding them? This is the MWE to reproduce:

\setupinteractionscreen[width=max,height=max]
\definepapersize[cover][width=330mm,height=240mm]
\definepapersize[book][width=160mm,height=240mm]
\setuppapersize[distance=38mm]
\setuplayout[backspace=18mm, width=129mm, height=223mm, marking=color]
\setuplayout[
   marking=color,
   location=middle,
   cropoffset=0mm,
   trimoffset=-7.5mm,
   bleedoffset=3mm]
\definelayer
  [foo]
  [width=\paperwidth,
  height=\paperheight]

\starttext
\pagebreak
\setuppapersize[cover][oversized]
\setlayer[foo][x=-19.5mm,y=-40.5mm]{
\startMPpage
StartPage;
numeric w, h, m;
w := bbwidth(Page);
h := bbheight(Page);
m := 19mm;
path p;
p := unitsquare xyscaled (w-2m,h-2m) shifted (m,m);
fill Page withcolor \MPcolor{yellow};
draw (.4889w,0) -- (.4889w,1h) withpen pensquare scaled 1pt withcolor
\MPcolor{black}; %testline
draw (.5111w,0) -- (.5111w,1h) withpen pensquare scaled 1pt withcolor
\MPcolor{black}; %testline
\stopMPpage}
\flushlayer[foo]
\pagebreak
\setuppapersize[book][oversized]
\dorecurse{5}{\samplefile{tufte}}
\stoptext

Op do 25 jun 2026 om 10:55 schreef Henning Hraban Ramm <[email protected]>:

> Am 25.06.26 um 10:22 schrieb Jeroen:
> > I want to generate a press-ready PDF book with cover with the following
> > but I dont seem to get the cover correct.
> >
> > - Trim size 320 × 240 mm
> > - MediaBox enlarged using \setuppapersize[cover][oversized]
> > - Crop marks (marking=color)
> > - Artwork extending into the bleed outside the TrimBox
> > - I am using LMTX v. 2026.04.27 on windows 11 Pro, 25H2
> >
> > 1. With the minimal example below, \startMPpage is clipped to Page so
> > the bleed area in the enlarged MediaBox remains white
> > 2. Is this the intended behaviour of \startMPpage? If so, what is
> > recommended to create artwork that extends into the bleed while keeping
> > the TrimBox and crop marks?
> >
> > \definepapersize[cover][width=320mm,height=240mm]
> > \definepapersize[book][width=160mm,height=240mm]
> > \setuppapersize[distance=38mm]
> > \setuplayout[backspace=18mm, width=129mm, height=223mm, marking=color]
> > \setuplayout[location=middle]
>
> You must set the PDF boxes like
>
> \setuplayout[
>    marking=color,
>    location=middle,
>    cropoffset=0mm,
>    trimoffset=-7.5mm,
>    bleedoffset=3mm,
> ]
> \setupinteractionscreen[width=max,height=max] % needed for activation
>
> I didn’t check if \startMPpage then still crops the image, I’d use
> \setlayer for placement.
>
> Hraban
>
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