These keywords define the grid and edge snapping parameters. These can be reset from within Xic from the Snapping page of the Grid Setup panels associated with the drawing windows. The parameters given in the technology file apply to the main window, which are inherited by sub-windows when created. The parameters can subsequently be changed with the panel on a per-window basis.
For the main drawing window, the Main Window sub-menu of the Attributes Menu provides the Set Grid button, which brings up the Grid Setup panel. Sub-windows have the Grid Setup panel available from the Attributes menu in the sub-window. Pressing Ctrl-g while a drawing window has focus will also bring up the panel.
This can be considered to be the ``pixel'' size of the mask. The SpotSize variable is related, see this topic in E.10 for more information.
The electrical grid is set to spacing value 1.0 with unit snap per grid on program startup, which can't be changed from the technology file. The electrical grid can be changed within Xic from the Grid Parameters pop-up, in the unusual circumstance that non-default values are needed.
If SnapPerGrid is given, then the fine grid lines will be spaced
num*SnapGridSpacing apart. If GridPerSnap is
given, fine grid lines will appear at SnapGridSpacing/num
EdgeSnapping some -off_grid -non_manh +edge_of_wires -path_of_wires
Only the first letter of the keywords is needed, and recognition is case-insensitive.
The first word specifies when edge snapping is enabled:
none not enabled some enabled in some commands (the default) all always enabled
The remaining items are flags that must start with a + or - character. The + turns the option on, the - turns the option off. These have obvious correspondence to the check boxes in the Edge Snapping control group in the Grid Setup panel, and set the initial state of the check boxes for the main window.