doc/emacs/picture-xtra.texi

1 @c This is part of the Emacs manual.
6 @c printed version) or in the main Emacs manual (for the on-line version).
10 @cindex making pictures out of text characters
13   To edit a picture made out of text characters (for example, a picture
14 of the division of a register into fields, as a comment in a program),
17   In Picture mode, editing is based on the @dfn{quarter-plane} model of
19 stretches infinitely far to the right and downward.  The concept of the end
20 of a line does not exist in this model; the most you can say is where the
21 last nonblank character on the line is found.
23   Of course, Emacs really always considers text as a sequence of
26 quarter-plane model of text.  They do this by inserting spaces or by
29   Most of the basic editing commands of Emacs are redefined by Picture mode
34   One of these keys, @kbd{C-c C-c}, is particularly important.  Often
35 a picture is part of a larger file that is usually edited in some
36 other major mode.  Picture mode records the name of the previous major
39 C-c} also deletes spaces from the ends of lines, unless given a
42   The special commands of Picture mode all work in other modes (provided
44 in Picture mode.  The descriptions below talk of moving ``one column''
54 * Basic Picture::         Basic concepts and simple commands of Picture Mode.
55 * Insert in Picture::     Controlling direction of cursor motion
66 @findex picture-move-down
67 @findex picture-move-up
74 end of the line makes no difference.  @kbd{C-b} is rebound to run
77 @kbd{C-p} are rebound to run @code{picture-move-down} and
78 @code{picture-move-up}, which can either insert spaces or convert tabs
80 @kbd{C-e} runs @code{picture-end-of-line}, which moves to after the last
81 nonblank character on the line.  @kbd{C-a} runs
82 @code{picture-beginning-of-line}.  (The choice of screen model does not
83 affect beginnings of lines; the only extra thing this command does is
87   Insertion of text is adapted to the quarter-plane screen model
88 through the use of Overwrite mode
97 @code{picture-newline}, which just moves to the beginning of the
98 following line so that new text will replace that line.
102 @findex picture-clear-line
108 character or characters with spaces, but does not move point.  (If you
109 want to clear characters to spaces and move forward over them, use
110 @key{SPC}.)  @kbd{C-k} (@code{picture-clear-line}) really kills the
111 contents of lines, but does not delete the newlines from the buffer.
113 @findex picture-open-line
115 (@code{picture-open-line}) creates a blank line after the current
116 line; it never splits a line.  @kbd{C-M-o} (@code{split-line}) makes
118 (@code{picture-duplicate-line}) inserts another line with the same
119 contents below the current line.
124 modes), or one of the picture rectangle commands (@pxref{Rectangles in
156   Since self-inserting characters in Picture mode overwrite and move
158 Normally point moves right, but you can specify any of the eight
198   Two motion commands move based on the current Picture insertion
209   Two kinds of tab-like action are provided in Picture mode.  Use
213 nonblank line.  ``Next'' here means ``appearing at a horizontal position
216 character in the current line.  @kbd{M-@key{TAB}} does not change the
218 the variable @code{picture-tab-chars}, which should define a set of
220 of @samp{[@dots{}]} in a regular expression---but without the @samp{[}
225 current tab stop settings; it is the Picture mode equivalent of
231   The context-based and tab-stop-based forms of tabbing are brought
234 would consider significant in the current line.  The use of this command,
235 together with @key{TAB}, can get the effect of context-based tabbing.  But
238   It may be convenient to prevent use of actual tab characters in
248   Picture mode defines commands for working on rectangular pieces of
289 rectangle commands in that they normally clear the rectangle instead of
293   However, deletion of rectangles can be useful in Picture mode, so
303 standard ones in that they overwrite instead of inserting.  This is
304 the same way that Picture mode insertion of other text differs from