Picture Mode Tabs
=================
Two kinds of tab-like action are provided in Picture mode. Use
`M-<TAB>' (`picture-tab-search') for context-based tabbing. With no
argument, it moves to a point underneath the next "interesting"
character that follows whitespace in the previous nonblank line.
"Next" here means "appearing at a horizontal position greater than the
one point starts out at." With an argument, as in `C-u M-<TAB>', this
command moves to the next such interesting character in the current
line. `M-<TAB>' does not change the text; it only moves point.
"Interesting" characters are defined by the variable
`picture-tab-chars', which should define a set of characters. The
syntax for this variable is like the syntax used inside of `[...]' in a
regular expression--but without the `[' and the `]'. Its default value
is `"!-~"'.
<TAB> itself runs `picture-tab', which operates based on the current
tab stop settings; it is the Picture mode equivalent of
`tab-to-tab-stop'. Normally it just moves point, but with a numeric
argument it clears the text that it moves over.
The context-based and tab-stop-based forms of tabbing are brought
together by the command `C-c <TAB>' (`picture-set-tab-stops'). This
command sets the tab stops to the positions which `M-<TAB>' would
consider significant in the current line. The use of this command,
together with <TAB>, can get the effect of context-based tabbing. But
`M-<TAB>' is more convenient in the cases where it is sufficient.
It may be convenient to prevent use of actual tab characters in
pictures. For example, this prevents `C-x <TAB>' from messing up the
picture. You can do this by setting the variable `indent-tabs-mode' to
`nil'. Note:Just Spaces.