[Tex/LaTex] How to prevent small values from being plotted with nodes near coords

pgfmathpgfplotstikz-pgf

I'm trying to finalize my first pgfplots chart. I've managed to get is almost the way I would like it to be with thanks to all examples I found here.
The last thing I can't seem to figure out is how to prevent plotting of value labels below 4% as they don't fit the bar (and small percentages aren't really relevant in this specific case).
I've found an example here on how to suppress the text from showing when the value is 0. I feel that it's just a small step to getting it to work. What I tried was to use \pgfmathfloatifflags and test for negative numbers on \pgfplotspointmeta minus 4. Would this work? I've not gotten it to work. I believe my understanding of the semantics of TeX/PGF is not adequate.

The result so far:
I tried to post an image here but as a new user I'm not allowed. Let me describe the issue: One data point has value 2. The bar segment of this data point is too small for the value to be plotted inside bar segment. It's overlapping now with another value. I would like small values to not be plotted in the chart.

The code I'm currently using is:

\documentclass{article}

\usepackage{tikz}
\usepackage{pgfplots}

\begin{document}

\pgfplotstableread{
y x1 x2 x3 ylabel
1   41  4 55 {Unit A}
2   60 2 38 {Unit B}
3   20 50 30 {Unit C}
4    0 20 80 {Unit D}
}\datatable

\begin{figure}
\caption{How to not show labels $<4\%$}
\centering
\begin{tikzpicture}
\begin{axis}[
    xbar stacked,
    legend style={
        legend columns=3,
        at={(xticklabel cs:0.5)},
        anchor=north,
        draw=none
    },
    ytick=data,
    axis y line*=left,
    axis x line*=bottom,
    tick label style={font=\footnotesize},
    legend style={font=\footnotesize},
    label style={font=\footnotesize},
    xtick={0,20,40,60,80,100},
    width=\textwidth,
    bar width=6mm,
    yticklabel style={text width=3cm, align=right},
    yticklabels from table={\datatable}{ylabel},
    xmin=0,
    xmax=100.1,
    y=8mm,
    enlarge y limits={abs=0.7},
    point meta=explicit,
    every node near coord/.style={
      check for zero/.code={
        \pgfmathfloatifflags{\pgfplotspointmeta}{0}{
           \pgfkeys{/tikz/coordinate}
        }{}
      }, check for zero, xshift=3, font=\scriptsize},
    nodes near coords={\pgfmathprintnumber[fixed zerofill,precision=0]{\pgfplotspointmeta}$\%$},
    nodes near coords align=left
]
\addplot table [x=x1, y=y, meta=x1] \datatable;
\addplot table [x=x2, y=y, meta=x2] \datatable;
\addplot table [x=x3, y=y, meta=x3] \datatable;
\legend{lorem,ipsum, dolor}

\end{axis}
\end{tikzpicture}
\label{fig:test}
\end{figure}
\end{document} 

Best Answer

Almost there! You only need to perform the subtraction in an extra step before doing the comparison, you can't put it right in the \pgfmathfloatifflags command.

Since the value of \pgfplotspointmeta is in floating point notation, you'll first have to switch on the fpu (the floating point unit) library using \pgfkeys{/pgf/fpu=true}, then perform the subtraction using \pgfmathparse{\pgfplotspointmeta-4}, check if the result is negative using \pgfmathfloatifflags{\pgfmathresult}{-}, and finally switch off the fpu library again.

\documentclass{article}

\usepackage{tikz}
\usepackage{pgfplots}

\begin{document}

\pgfplotstableread{
y x1 x2 x3 ylabel
1   41  4 55 {Unit A}
2   60 2 38 {Unit B}
3   20 50 30 {Unit C}
4    0 20 80 {Unit D}
}\datatable

\begin{figure}
\caption{How to not show labels $<4\%$}
\centering
\begin{tikzpicture}
\begin{axis}[
    xbar stacked,
    legend style={
        legend columns=3,
        at={(xticklabel cs:0.5)},
        anchor=north,
        draw=none
    },
    ytick=data,
    axis y line*=left,
    axis x line*=bottom,
    tick label style={font=\footnotesize},
    legend style={font=\footnotesize},
    label style={font=\footnotesize},
    xtick={0,20,40,60,80,100},
    width=\textwidth,
    bar width=6mm,
    yticklabel style={text width=3cm, align=right},
    yticklabels from table={\datatable}{ylabel},
    xmin=0,
    xmax=100.1,
    y=8mm,
    enlarge y limits={abs=0.7},
    point meta=explicit,
    every node near coord/.style={
      check for zero/.code={
        \pgfkeys{/pgf/fpu=true}
        \pgfmathparse{\pgfplotspointmeta-4}
        \pgfmathfloatifflags{\pgfmathresult}{-}{
           \pgfkeys{/tikz/coordinate}
        }{}
        \pgfkeys{/pgf/fpu=false}
      }, check for zero, xshift=3, font=\scriptsize},
    nodes near coords={\pgfmathprintnumber[fixed zerofill,precision=0]{\pgfplotspointmeta}$\%$},
    nodes near coords align=left
]
\addplot table [x=x1, y=y, meta=x1] \datatable;
\addplot table [x=x2, y=y, meta=x2] \datatable;
\addplot table [x=x3, y=y, meta=x3] \datatable;
\legend{lorem,ipsum, dolor}

\end{axis}
\end{tikzpicture}
\label{fig:test}
\end{figure}
\end{document}