Margin notes, multicols, tikz overlay

Question

As seen on page 200 of pgf manual is there a way to put notes in the margin but on the same level as the place it is called ?

One can deal with the right-left positionning with the help of this question margin notes multicolumn, but how to deal with up-down level ?

Edit

With your help, here is my try. Still vertical alignement problem.

\documentclass[french]{article}
\usepackage[marginparsep=3pt, top=2cm, bottom=1.5cm, left=1.5cm, right=1.5cm]{geometry}
\setlength{\parindent}{0pt}
\setlength{\headsep}{1em}
\usepackage{tikz,lipsum}
\usepackage{multicol,zref-savepos}

\def\Note#1{%
\zsavepos{#1}%
%%%%%%--------
\ifnum20000000<\number\zposx{#1}%
    \begin{tikzpicture}[remember picture,overlay]
    \coordinate (here) at (0,0);
    \draw (current page.east |- here)
            node[left]{\makebox[1.2cm][l]{#1}};
    \end{tikzpicture}%to prevent adding extra space before text
\else
    \begin{tikzpicture}[remember picture,overlay]
    \coordinate (here) at (0,0);
    \draw (current page.west |- here)
            node[right]{\makebox[1.2cm][r]{#1}};
    \end{tikzpicture}%to prevent adding extra space before text
\fi%
\ignorespaces
}

\begin{document}
\begin{multicols}{2}

\lipsum[1]

Un essai de note dans la colonne de gauche.\hfill\Note{1pt}

\lipsum[2-3]

\Note{1.5pt} Un essai de note dans la colonne de droite.
\lipsum[4-5]
\end{multicols}

\end{document}

Answer 1

I'm surprised this works. The actual location of the origin isn't usually fixed until the picture is completed and the current bounding box is fit into the text area.

\documentclass{article}
\usepackage{tikz}
\usepackage{lipsum}

\begin{document}

\lipsum[1]

\begin{tikzpicture}[remember picture,overlay]
\coordinate (here) at (0,0);
\draw (current page.west |- here) node[right]{Margin note};
\end{tikzpicture}%to prevent adding extra space before text
\lipsum[2-4]

\end{document}

Answer 2

You can also use Tikz to perform the left column/right column test. Also, putting a \strut inside the nodes will give more consistent results wrt vertical centering, and it looks better with the calculated offset: 0.15\baselineskip.

\documentclass[french]{article}
\usepackage[marginparsep=3pt, top=2cm, bottom=1.5cm, left=1.5cm, right=1.5cm]{geometry}
\setlength{\parindent}{0pt}
\setlength{\headsep}{1em}
\usepackage{tikz,lipsum}
\usepackage{multicol}

\newlength{\test}

\def\Note#1{%
\begin{tikzpicture}[remember picture,overlay]
\coordinate (here) at (0,0.15\baselineskip);
%compute horizontal offset from origin to center
\pgfextractx{\test}{\pgfpointdiff{\pgfpointorigin}
  {\pgfpointanchor{current page}{center}}}%
\ifdim\test < 0pt%
  \draw (current page.east |- here)+(-1.5cm,0pt) node[right]{\strut #1};
\else
  \draw (current page.west |- here)+(1.5cm,0pt) node[left]{\strut #1};
\fi%
\end{tikzpicture}%
\ignorespaces%
}%

\begin{document}
\begin{multicols}{2}

\lipsum[1]

Un essai de note dans la colonne de gauche.\hfill\Note{pyg}

\lipsum[2-3]

\Note{CAP} Un essai de note dans la colonne de droite.
\lipsum[4-5]
\end{multicols}

\end{document}

Answer 3

I like John's idea about the columns. I distrust niggly adjustmants (0.15\baselineskip) and would rather have tikz do the work of positioning things correctly. The best thing to do is to use anchor=text in the nodes. Also changed the text alignment depending on whether it is on the left or right side. Fiddle with the dimensions to suit.

\documentclass[french]{article}
\usepackage[top=2cm, bottom=1.5cm, left=1.5cm, right=1.5cm]{geometry}
\setlength{\parindent}{0pt}
\setlength{\headsep}{1em}
\usepackage{tikz,lipsum}
\usepackage{multicol}

\newlength{\test}

\def\Note#1{%
\begin{tikzpicture}[remember picture,overlay]
\coordinate (here) at (0,0);
%compute horizontal offset from origin to center
\pgfextractx{\test}{\pgfpointdiff{\pgfpointorigin}
  {\pgfpointanchor{current page}{center}}}%
\ifdim\test < 0pt%
  \draw (current page.east |- here)+(-0.5in,0pt) node[anchor=text,align=left,text width=0.5in]{\strut #1};
\else
  \draw (current page.west |- here)+(0cm,0pt) node[anchor=text,align=right,text width=0.5in]{\strut #1};
\fi%
\end{tikzpicture}%
\ignorespaces%
}%

\begin{document}
\begin{multicols}{2}

\lipsum[1]

Un essai de note dans la colonne de gauche.\Note{pyg}

\lipsum[2-3]

\Note{CAP}% and more} 
Un essai de note dans la colonne de droite.
\lipsum[4-5]
\end{multicols}

\end{document}