I can not help thinking of this bed leveling scenario.
Why not use the relevant x/y coordinates of the object to be printed to set boundaries for the probing area.
To me that would give tighter/better measurements for small objects and faster probing ?
I see no need to cover the whole bed when doing small objects ?
If the slicer provided information on the horizontal size of the print at the start of the file, it would be easy. But slicers don't do that. So the firmware would have to scan the whole of the GCode for the first layer to determine the size. Where the print includes a skirt and it is labeled as such by the slicer, scanning just the GCodes for the skirt would do.
I think it's rare for users to run mesh bed probing before every print. More usually, the height map is saved to SD card or EEPROM so that it can be recalled without probing again.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
