[latex3-commits] [git/LaTeX3-latex3-pdfresources] testA4: some docu about mediabox (e5cab07)

[Ulrike Fischer]

Repository : https://github.com/latex3/pdfresources
On branch  : testA4
Link       : https://github.com/latex3/pdfresources/commit/e5cab07bc1df2bb4cef1be42b02a34c7abe6db96

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commit e5cab07bc1df2bb4cef1be42b02a34c7abe6db96
Author: Ulrike Fischer <fischer at troubleshooting-tex.de>
Date:   Sun May 8 23:46:54 2022 +0200

    some docu about mediabox


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e5cab07bc1df2bb4cef1be42b02a34c7abe6db96
 l3pdfmanagement.dtx | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/l3pdfmanagement.dtx b/l3pdfmanagement.dtx
index fb8ca85..de32b35 100644
--- a/l3pdfmanagement.dtx
+++ b/l3pdfmanagement.dtx
@@ -360,6 +360,20 @@
 %   Values added to \texttt{ThisPage} can not be removed. It is not possible to
 %   show the content of this dictionary with \cs{pdfmanagement_show:n}.
 % \end{function}
+%
+% \paragraph{Changing the \texttt{/MediaBox}}: It is possible to change
+% the \texttt{/MediaBox} of one or more pages by setting it for the \texttt{Page}
+% or \texttt{ThisPage} path (using \texttt{Pages} doesn't work, the engines
+% overwrite this)---this works even with dvips and allows to create
+% pages of different sizes. But you must be careful with the values.
+% If you set e.g. with pdflatex \cs{pdfpageheight} to 300bp you get a mediabox of
+% |0 0 595 300|, but pdflatex measure from the top and will also move
+% the reference point up, so effectivly
+% you get the \emph{upper} third of the page. If you set the \texttt{/MediaBox}
+% to |0 0 595 300| with \cs{pdfmanagement_add:nnn} you get the \emph{lower} third.
+% In general it is better to use only the primitive commands to avoid confusing
+% results.
+%
 % \subsubsection{\enquote{Page/Resources}: ExtGState, ColorSpace, Shading, Pattern}
 % \begin{NOTE}{UF}
 % Only for pdf/luatex and xdvipdfmx backend- and pdf-code is needed to add values