Hello,
how are the internal variables GPVAL_TERM_* defined, i.e. how are they calculated and what do their values mean exactly? (and which unit do they have?)
I have an idea for a possible answer for my own question on stackoverflow, but for that I'd need a better understanding about these variables. Unfortunately the doc doesn't tell much about them.
If the definition of these variables depends on the terminal, then I specifically ask about cairolatex
only.
I put an answer to your original question on stackoverflow.
The GPVAL_TERM_* variables provide a user-visible view of various internal state variables but they will not help you for this purpose. Gnuplot has no way of knowing where TeX will place the generated text, so it has no relevant internal state to export.