GNU Emacs Lisp Reference Manual

35.14.2: Active Display Table

Each window can specify a display table, and so can each buffer. When a buffer b is displayed in window w, display uses the display table for window w if it has one; otherwise, the display table for buffer b if it has one; otherwise, the standard display table if any. The display table chosen is called the active display table.

Function: window-display-table window

This function returns window's display table, or nil if window does not have an assigned display table.

Function: set-window-display-table window table

This function sets the display table of window to table. The argument table should be either a display table or nil.

Variable: buffer-display-table

This variable is automatically local in all buffers; its value in a particular buffer is the display table for that buffer, or nil if the buffer does not have an assigned display table.

Variable: standard-display-table

This variable's value is the default display table, used whenever a window has no display table and neither does the buffer displayed in that window. This variable is nil by default.

If there is no display table to use for a particular window---that is, if the window has none, its buffer has none, and standard-display-table has none---then Emacs uses the usual display conventions for all character codes in that window. See Usual Display.