wm grid

wm grid window ?baseWidth baseHeight widthInc heightInc?

This Tk command indicates that window is to be managed as a gridded window. It also specifies the relationship between grid units and pixel units. BaseWidth and baseHeight specify the number of grid units corresponding to the pixel dimensions requested internally by window using Tk_GeometryRequest. WidthInc and heightInc specify the number of pixels in each horizontal and vertical grid unit. These four values determine a range of acceptable sizes for window, corresponding to grid-based widths and heights that are non-negative integers. Tk will pass this information to the window manager; during manual resizing, the window manager will restrict the window's size to one of these acceptable sizes.

Furthermore, during manual resizing the window manager will display the window's current size in terms of grid units rather than pixels. If baseWidth etc. are all specified as empty strings, then window will no longer be managed as a gridded window. If baseWidth etc. are specified then the return value is an empty string.

Otherwise the return value is a Tcl list containing four elements corresponding to the current baseWidth, baseHeight, widthInc, and heightInc; if window is not currently gridded, then an empty string is returned.

You probably do not want to use this command; setting the -grid option on a text widget (the primary use of gridded geometry management) is far simpler.