DISPLAYEDGE dot command allows user to store information about visible area of their display in global configuration file /sys/env.cfg
To launch the tool enter .displayedge in command-line, there are no command line arguments (yet).
SPACE : select active corner of display (top left vs bottom right) arrows : edit visible position of the active corner ("cursor joystick") (also Kempston/MD controller can be used, fire then selects corner) Q : exit back to NextZXOS R : reload the cfg file currently stored on disk (discards any changes) S : save the currently modified values to cfg file F : change between 50Hz/60Hz mode (also regular "F3" key works) T : in VGA modes you can switch between different video-mode timings (Q/R/S/F/T usually requires confirmation by pressing "Y" after)
Some other SW may then read the global configuration file and adjust the playfield area of the SW to avoid displaying important information in invisible (on your display) areas.
The configuration file can be also edited in any text editor, keywords (variables) used by displayedge:
edge_hdmi_50, edge_zx48_50, edge_zx128_50, edge_zx128p3_50, edge_hdmi_60, edge_zx48_60, edge_zx128_60, edge_zx128p3_60, edge_pentagon
For particular mode the line should be keyword=0,1,2,3 where the numbers are amount of invisible pixels on particular edge in order: left, right, top, bottom (valid values are 0 to 31).
If you are creating your own SW and you want to read the configuration, you can use the provided "runtime" part of the code: displayedge_rt.i.asm (check also the project README and source comments for more detailed info about usage).
The DISPLAYEDGE dot command and source code is (c) 2020 of Peter Helcmanovsky, published under MIT license, for latest version of sources or to report issue use the github repository of the project: https://github.com/ped7g/ZXSpectrumNextMisc (latest version is v2.2 from 2021-01-23)