On Sat, Jun 22, 2019 at 2:04 PM Sławomir Osipiuk via Unicode < [email protected]> wrote:
> I see there is no such character, which I pretty much expected after > Google didn’t help. > > > > The original problem I had was solved long ago but the recent article > about watermarking reminded me of it, and my question was mostly out of > curiosity. The task wasn’t, strictly speaking, about “padding”, but about > marking – injecting “flag” characters at arbitrary points in a string > without affecting the resulting visible text. I think we ended up using > ESC, which is a dumb choice in retrospect, though the whole approach was a > bit of a hack anyway and the process it was for isn’t being used anymore. > The spec would suggest that there are escape codes like that, which can be used. APC, <Application Program Command> U+009F ST, String Terminator, U+009C which is supposed to be a sequence of characters that should not be displayed, but may be used to control the application displaying them. (assuming they understand them) https://www.aivosto.com/articles/control-characters.html 156$9CSTString Terminator 234 9/12 ST ESC \ Closes a string opened by APC, DCS, OSC, PM or SOS. 159$9FAPCApplication Program Command 237 9/15 AC ESC _ Starts an application program command string. ST will end the command. The interpretation of the command is subject to the program in question. But it doesn't appear anything actually 'supports' that.

