externalize only some pictures

The global externalization setting can be temporary disabled/enabled (until the end of the TeX group) using \tikzexternaldisable and \tikzexternalenable. Another option is to set the /tikz/external/export={true/false} key; the variant /tikz/external/export next={true/false} applies only for a single picture.

All these are described in the chapter "Externalization Library" of the TikZ userguide.

1. put this at the begin of your preamble

   \usepackage{etoolbox}
   \providetoggle{externalize}
   \settoggle{externalize}{true}
   

2. put this at the end of your preamble, and most important, after \makeindex

   \newcommand{\notexternal}{%
     \iftoggle{externalize}{\tikzset{external/export next=false}}{}
   }
   
   \iftoggle{externalize}{\tikzexternalize[prefix=figures-compiled/]}{}
   

3. put \notexternal before tikz environment/command you don't want to be externalized

In this way:

• you have a short command to disable externalization for a single picture
• you can disable externalization for the whole document by changing \settoggle{externalize}{true} to \settoggle{externalize}{true}, without having to change anything else

EDIT: Alternative version

Externalized pictures are named incrementally, and if you add/remove/swap pictures in your document you have to recompile them all, unless you specify the name for each picture, which can be done with this code:

1. unchanged

2. new code:

   \newcommand{\externalize}[1][]{%
     \iftoggle{externalize}{%
       \ifstrequal{#1}{false}{%
         \tikzset{external/export next=false}%
       }{%
         \ifstrempty{#1}{%
           \ifcurrfiledir{./figures/}{%
             \tikzsetnextfilename{\currfilebase}
           }{}
         }{%
           \tikzsetnextfilename{#1}
         }
       }
     }{}
   }
   
   \iftoggle{externalize}{\tikzexternalize[prefix=figures-compiled/]}{}
   

3. three alternatives:

   • put \externalize[false] before tikz environment/command you don't want to be externalized
   • put \externalize[figure_a] if you want the external picture to be named figure_a.pdf
   • if the picture is included in your document with \include{./figures/figure_1.tex}, you can put \externalize with no argument if you want the external picture to be named figure_1.pdf (if the file is not in the figures folder, it will be named incrementally)
   • don't put anything if you want the figure to be externalized and named incrementally