ofToString() does not report all digits of precision

[kylemcdonald]

ofToString() should always return as many digits of precision as are available from the floating point value. it looks like right now, at least 2 or 3 digits of precision are being ignored. this was not a problem with sprintf(), but is a problem with stringstream. this problem first became clear with issue #1516 and a temporary fix was made to ofxXmlSettings, but a deeper fix to ofToString() still needs to be made.

[bilderbuchi]

We can probably use the two SO questions I linked to in #1516 to code a mechanism which automatically determines the needed precision from the templated argument of ofToString(const T & value)?

http://stackoverflow.com/questions/2330850/correct-way-to-set-maximum-double-precision-for-ostringstream
http://stackoverflow.com/questions/554063/how-do-i-print-a-double-value-with-full-precision-using-cout

[artificiel]

perhaps time to move to fmtlib (std::format in C++20) and solve this correctly? beyond the flexibility of the formatting system (covering most if not all ofToString stuff, and providing of course much more), it handles round-trip guarantees for floating point values.

I've been using it for a while and it's only a matter of including the header.

[dimitre]

+1 for fmtlib added to apothecary, so we can fix other format warnings on the core.