Drawing and inserting mathematical symbols on a Dia generated graph

In Dia, export the figure into "Latex PGF Macro". So the file becomes xxx.tex

Modify the tex file and find something like: if you have latex symbol in the figure "&" such as:

{smooth ensuremath{blackslash}&} change it to
{smooth ensuremath{&}}

In the head of latex document, add

usepackage{tikz}

In the document use :

begin{figure*}
    label{fig-flowchart}
     centerline{
            resizebox{6in}{!}{input{newfig/flowchart.tex}}
    }
           caption{ The general flowchart of similarity learning process for quality assurance. }
end{figure*}

It works for me.

You can also use inkspace's export to pdf_tex, however, you should have tex written in the inkspace A's box, otherwise, there's newline and font problem.

There is a patch to keep TeX formulae unescaped in PGF export. Hopefuly, it will be merged soon.

See https://bugzilla.gnome.org/show_bug.cgi?id=778836 and https://gitlab.gnome.org/GNOME/dia/merge_requests/3

Alternatively you can input the respective Unicode characters:

In a text box in dia press Ctrl+Shift+U, release the U, then type the UTF-32 hex code for the characters you want. For example for alpha this would be 3b1.

If you have the complete drawing in Dia, you can chose to export the picture as LaTeX PGF macros. You'll then have a .tex file, lets say yourDiaDrawing.tex, which you can include in your document by input{pathToFile/yourDiaDrawing.tex}. If you have added your labels in Dia, find the nodes containing your label texts in yourDiaDrawing.tex. When exporting to TikZ, Dia assumes that every special character you have inserted are supposed to be that way, and escapes the characters. So your math dollars will be escaped $, your backslashes will be escaped \ and so on. Remove the backslash, and LaTeX does the rest.

You'll probably find nodes in yourDiaDrawing.tex that'll look something like this

node[anchor=west] at (13.00du,8.00du){$ \alpha $};

Final

documentclass[pstricks,border=12pt,12pt]{standalone}
usepackage{amsmath}
usepackage{pst-plot,pst-node}
psset{algebraic,plotpoints=100,labelsep=3pt}

deff[#1,#2]{2*2^(-2.5*(#1-#2)^2)}

begin{document}
begin{pspicture}[showgrid=false](-3,0)(3.5,3)
    psaxes[axesstyle=frame,tickstyle=bottom,ticks=x,ticksize=0 4pt,xsubticks=5,xsubticksize=.5,labels=none](0,0)(-3,0)(3,3)
    uput[d](-1,0){$omega_{text{nl}}$}
    uput[d](1.5,0){$omega_{text{lin}}$}
    uput[d](0,0){tiny Frequency}
    psline{<-}(0,2)(1,2)
    psset{linecolor=gray}
    psline[linestyle=dashed](0,0)(0,3) 
    psplot[linecolor=red,linestyle=dashed]{-3}{1}{f[x,-1]}
    psplot[linecolor=red]{-.5}{3}{f[x,1.5]}
    pcline{<->}(*-1.5 {f[x,-1]})(*-.5 {f[x,-1]})nbput{$r_{text{nl}}$}
    pcline{<->}(*1 {f[x,1.5]})(*2 {f[x,1.5]})nbput{$r_{text{lin}}$}
end{pspicture}
end{document}