Watermark on a standalone document. - TeX

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Top Answer

user 3.14159

In case this is in any way related to your previous question on frames around `standalalone` documents, and also if it is not, then there is good news: you can enhance the boxes from the previous `tcolorbox` answer to allow for watermarks. Ironically, you really basically need to add the `enhanced` key to get access to these features (and load the `skins` library). In fact, `tcolorbox` comes with an extended support for watermarks, which are described in section 10.3 of manual v4.31. Since there is no mention of a frame, for the time being I switched it off with `colframe=white` (there are other ways, of course). 

```
\documentclass[border=3mm]{standalone}
\usepackage[skins]{tcolorbox}
\newtcolorbox{mybox}[1][]{hbox,colback=white,colframe=white,
watermark color=blue,watermark opacity=0.3,
enhanced,boxsep=3cm,#1}
\standaloneenv{mybox}
\begin{document}
\begin{mybox}[watermark text=pft]
Hello world!
\end{mybox}
\begin{mybox}[watermark text=quack]
Hello ducks!
\end{mybox}
\end{document}
```
![ani.gif](/image?hash=ffc1d8d7172446226ee16f6541823de9271170502753861425bfee41ffb363a3)

You can then create whatever watermark you like. Just to give an (admittedly not overly nice) example, you can typeset the watermark text along a circle.
```
\documentclass[border=3mm]{standalone}
\usepackage[skins]{tcolorbox}
\usepackage{tikz}
\usetikzlibrary{decorations.text}
\newtcolorbox{mybox}[1][]{hbox,colback=white,colframe=white,
watermark color=blue,watermark opacity=0.3,
enhanced,boxsep=3cm,#1}
\tcbset{circular watermark/.style={watermark tikz={%
\pgfmathsetmacro{\myr}{0.2cm+1*width("#1")/2/pi}%
\pgfmathsetmacro{\myR}{\myr+height("#1")-2pt}%
\path[decorate,decoration={text along path,text align={align=center},
raise=-0.15ex,text={|\sffamily|#1}}] 
(0,-\myr pt) arc[start angle=270,end angle=-90,radius=\myr pt];
% necessary to get the bounding box right
\path (0,-\myR pt) arc[start angle=270,end angle=-90,radius=\myR pt];
}}}
\standaloneenv{mybox}
\begin{document}
\begin{mybox}[circular watermark=pft]
Hello world!
\end{mybox}
\begin{mybox}[circular watermark=meow]
Hello cats!
\end{mybox}
\begin{mybox}[circular watermark=quack]
Hello ducks!
\end{mybox}
\end{document} 
```
![ani.gif](/image?hash=0383a0551c14206b582da561e92bf084f6eea39a80912b4e7461957b4e4d82cb)

Answer #2

Skillmon

There are 3 code versions in this answer:

1. using the development version of LaTeX
1. using `eso-pic` instead of the development version of the kernel
1. an example with an auto-scaling watermark

## Development kernel version

The following uses the new hook-mechanism provided in the development version of the LaTeX kernel (so you need to compile this with `pdflatex-dev`, `lualatex-dev` or `xelatev-dev`).

It also requires `xfp` for the placement, both `xcolor` and `graphics` are only needed for the used contents of `\mywatermark`.

```
\documentclass{standalone}

\usepackage{xcolor}
\usepackage{graphics}
\usepackage{xfp}

\newcommand*\mywatermark{\rotatebox{30}{\sffamily\color{gray}\huge watermark}}

\AddToHook{shipout/background}
  {%
    \setlength\unitlength{1pt}%
    \put(\fpeval{1in+0.5*\paperwidth},\fpeval{-1in-0.5*\paperheight})
      {%
        \sbox0{\makebox[0pt][c]{\mywatermark}}%
        \raise.5\dimexpr\dp0-\ht0\relax\box0
      }%
  }


\begin{document}
\parbox[t][5cm]{10cm}{Hello world}
\end{document}
```

![test-1.png](/image?hash=0ee9b3c6cc4e4b42f866f43eb4747f70eb5b97ea51c167384c467090864a57a0)

----

## `eso-pic` version

Without the development versions, you can use `eso-pic` with the option `texcoords` (just so I don't have to change the rest of the code). So the following works in current versions of LaTeX:

```
\documentclass{standalone}

\usepackage{xcolor}
\usepackage{graphics}
\usepackage{xfp}
\usepackage[texcoord]{eso-pic}

\newcommand*\mywatermark{\rotatebox{30}{\sffamily\color{gray}\huge watermark}}

\AddToShipoutPictureBG
  {%
    \setlength\unitlength{1pt}%
    \put(\fpeval{1in+0.5*\paperwidth},\fpeval{-1in-0.5*\paperheight})
      {%
        \sbox0{\makebox[0pt][c]{\mywatermark}}%
        \raise.5\dimexpr\dp0-\ht0\relax\box0
      }%
  }


\begin{document}
\parbox[t][2cm]{5cm}{Hello world}
\end{document}
```

(results are the same as above, so no new picture)


-----------

## Auto-scaling example

Just to show, that auto-scaling is possible, the following uses `adjustbox` and its `max totalsize` key for the that.

```
\documentclass{standalone}

\usepackage{xcolor}
\usepackage{graphics}
\usepackage{xfp}
\usepackage[texcoord]{eso-pic}
\usepackage{adjustbox}

\newcommand*\mywatermark
  {%
    \adjustbox
      {max totalsize={\paperwidth}{\paperheight}}%
      {\rotatebox{30}{\sffamily\color{gray}\huge watermark}}%
  }

\AddToShipoutPictureBG
  {%
    \setlength\unitlength{1pt}%
    \put(\fpeval{1in+0.5*\paperwidth},\fpeval{-1in-0.5*\paperheight})
      {%
        \sbox0{\makebox[0pt][c]{\mywatermark}}%
        \raise.5\dimexpr\dp0-\ht0\relax\box0
      }%
  }

\begin{document}
Hello World!
\end{document}
```

![watermark-1.png](/image?hash=0743b5c7df6decec35a6ed2cd58087805ac84d2ed3ead5c62d28cbb463822d70)

"I still think that having full control over ones watermark ... is an advantage": I agree, which is why I brought up the `tcolorbox` solution, where one has full control "out of the box". Everything is very cleanly controlled by pgf keys, no need to add another package and rewrite everything for every additional feature. All the options have been thoroughly tested, and there is a nicely written manual that allows one to look up things. I stress that this not by any means my achievement, everything is done by `tcolorbox`, a well written and maintained package. If you disagree with that and deem your developer or other solutions superior, this is your choice, and it is not my aim to change your opinion, nor to continue this exchange.

You do realise that there is a big difference between being bad and being disadvantageous? I should've included an "imho", because obviously this is a matter of taste, but I still think that having full control over ones watermark by only changing the definition of a single macro is an advantage (a definition that can indeed contain auto-scaling).

IMHO it does not make much sense to continue this exchange. You posted an answer that suggested that one needs a developer version of LaTeX to solve the problem (which one absolutely does not), and which adds shifts by `1in` without an explanation (maybe the reason is obvious to the general reader, but I doubt it), and which, yes, hardcodes the dimensions of the output, i.e. the size of the result is independent of the contents of the `\parbox`, which IMHO is the opposite of what one typically wants to achieve with a `standalone` document. But sure enough you discard all these points, and state that the autoscaling of the watermark (which of course can be switched off) is bad. Let's just agree to disagree. These are strange times, users who go after others by criticizing the choice of editor used in a perfectly working library and documentation get applauded these days, and I am sure you will also find supporters, but I am not willing to engage in these kind of exchanges.

The fact that one needs to know about the `1in` shifts stems from the point of injection. In `tcolorbox` the watermark is added before `standalone` does its thing, with my code afterwards, that's all there is to it. The biggest difference is that my code doesn't auto-scale the watermark, which is indeed an advantage (if it is wanted) of the `tcolorbox` approach (and I'm sure that `tcolorbox` supports some way of not auto-scaling the watermark).

Yes, sure. I just tried to understand where the need to use a development version of LaTeX and the manual shifts by `1in` came from... but this didn't go well. I actually do not know where the claim "for your code the contents might always be bigger than the watermark," comes from, but luckily everyone can just run my codes to see that this is nonsense.

No. That's absolutely not the case. And as I said I do not hardcode the page dimensions, you do. Since you seem to disagree with this: if you change in your code `Hello world` to `Hello ducks and marmots`, the size won't change because it is fixed by the dimensions of the `\parbox`. On the other hand, with `tcolorbox` everything automatically adjusts to the input, but you have the *flexibility* to have fixed dimensions. IMHO this is the difference between hard coding and not hard coding. Besides, one does not have to know about the `1in` manual shifts.

which is quite a difference, isn't it? For my code the contents just have to be bigger than the watermark and everything will work out, for your code the contents might always be bigger than the watermark, but you'll always have a margin, even if it's not necessary. Hence I don't see the advantage of your code over mine for the sake of this answer, the user has to pay attention and make manual adjustments either way.

Well, `tcolorbox` does have the ability to adjust the size of the watermark to the content. I actually do like this ability, and if one does not like it, one can turn it off. IMHO it does not hurt to have all these options as long as you have some keys that allow you to turn them on and off at will. Why should not having the options be better?

I don't hardcode the page dimensions. I just create content of arbitrary sizes. The code doesn't depend on the sizes at all. It is possible to first typeset the watermark and check whether it'll fit and resize if it doesn't, but that code seems boring to add and not specific to this question.

I personally think it is better not to hardcode the page dimensions. BTW, if you go this way, you can simplify things to ``` \documentclass[border=3cm]{standalone} \usepackage{xcolor} \usepackage{graphics} \usepackage[texcoord]{eso-pic} \newcommand*\mywatermark{\rotatebox{30}{\sffamily\color{gray}\huge watermark}} \AddToShipoutPictureBG {% \AtPageCenter{\put(\LenToUnit{1in},\LenToUnit{-1in}){% $\vcenter{\makebox[0pt][c]{\mywatermark}}$}}% } \begin{document} Hello world \end{document} ```

In this version you do not need to hardcode the dimensions of the page. That is, you can just drop the parbox: ```` \documentclass[border=3cm]{standalone} \usepackage{xcolor} \usepackage{graphics} \usepackage{xfp} \usepackage[texcoord]{eso-pic} \newcommand*\mywatermark{\rotatebox{30}{\sffamily\color{gray}\huge watermark}} \AddToShipoutPictureBG {% \setlength\unitlength{1pt}% \put(\fpeval{1in+0.5*\paperwidth},\fpeval{-1in-0.5*\paperheight}) {$\vcenter{\makebox[0pt][c]{\mywatermark}}$}% } \begin{document} Hello world \end{document} ```

The reasoning was, that either you're using it with Ti*k*Z, in which case you could/should add the watermark using Ti*k*Z, or to create small stuff to embed in your own documents. I never considered creating contents for social media, tbh.

Oops! Why do you think so? I am using standalone class for developing social media images, I need to add watermark on it. So many people like me might want to add a watermark on a standalone document. What made you think that nobody would need this. I am curious.

And yes, I just set the dimensions manually to make sure the automatic placement gives the correct results, so I changed the size of the `\parbox` a few times and `5cm` and `10cm` are just the last two values I tried.

The way I set this up might also work with `eso-pic` (I haven't tested), so you might indeed not need the developer version. I created that also to get some experience with the new hooks myself. The `1in` and `-1in` come from the way `standalone` crops things or rather the page dimensions, if you take a look at how LaTeX sets up the page margins, you'll notice that for both `\hoffset` and `\voffset` an additional inch is used (see for example the [wikibook](https://en.wikibooks.org/wiki/LaTeX/Page_Layout#Page_dimensions)).

@निरंजन, If this is in any way related to the question about the frames around `standalone` documents, I think there would again be a very simple `tcolorbox` solution. Of course, you do not need to draw a frame, but `tcolorbox`es can easily be amended by a watermark.

@Skillmon Naively I would think that, if you set the page dimensions by hand via `\parbox`, you do not need a developer version of LaTeX. Things do indeed get more tricky if you do not set the dimensions by hand. It would also be interesting to understand where the additional manual shifts by `1in` and `-1in` come from.

@निरंजन, re: [your question](#question), Can you give a bit more background information about the actual use case? Will the document contain more than one page? If yes with the same sizes? Will the actual document be by any change a tikzpicture?

2 Answers