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6f585e44 | 1 | @c This is part of the Emacs manual. |
114f9c96 | 2 | @c Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. |
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3 | @c See file emacs.texi for copying conditions. |
4 | @c | |
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5 | @c This file is included either in emacs-xtra.texi (when producing the |
6 | @c printed version) or in the main Emacs manual (for the on-line version). | |
7 | @node Picture Mode | |
8 | @chapter Editing Pictures | |
9 | @cindex pictures | |
10 | @cindex making pictures out of text characters | |
a2baab5c | 11 | @findex picture-mode |
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12 | |
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), | |
a2baab5c | 15 | use the command @kbd{M-x picture-mode} to enter Picture mode. |
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16 | |
17 | In Picture mode, editing is based on the @dfn{quarter-plane} model of | |
18 | text, according to which the text characters lie studded on an area that | |
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. | |
22 | ||
23 | Of course, Emacs really always considers text as a sequence of | |
24 | characters, and lines really do have ends. But Picture mode replaces | |
25 | the most frequently-used commands with variants that simulate the | |
26 | quarter-plane model of text. They do this by inserting spaces or by | |
27 | converting tabs to spaces. | |
28 | ||
29 | Most of the basic editing commands of Emacs are redefined by Picture mode | |
30 | to do essentially the same thing but in a quarter-plane way. In addition, | |
31 | Picture mode defines various keys starting with the @kbd{C-c} prefix to | |
32 | run special picture editing commands. | |
33 | ||
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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 | |
37 | mode so you can use the @kbd{C-c C-c} command | |
38 | (@code{picture-mode-exit}) later to go back to that mode. @kbd{C-c | |
39 | C-c} also deletes spaces from the ends of lines, unless given a | |
40 | numeric argument. | |
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41 | |
42 | The special commands of Picture mode all work in other modes (provided | |
43 | the @file{picture} library is loaded), but are not bound to keys except | |
44 | in Picture mode. The descriptions below talk of moving ``one column'' | |
45 | and so on, but all the picture mode commands handle numeric arguments as | |
46 | their normal equivalents do. | |
47 | ||
48 | @vindex picture-mode-hook | |
49 | Turning on Picture mode runs the hook @code{picture-mode-hook}. | |
50 | Additional extensions to Picture mode can be found in | |
51 | @file{artist.el}. | |
52 | ||
53 | @menu | |
54 | * Basic Picture:: Basic concepts and simple commands of Picture Mode. | |
55 | * Insert in Picture:: Controlling direction of cursor motion | |
56 | after "self-inserting" characters. | |
57 | * Tabs in Picture:: Various features for tab stops and indentation. | |
58 | * Rectangles in Picture:: Clearing and superimposing rectangles. | |
59 | @end menu | |
60 | ||
61 | @node Basic Picture | |
62 | @section Basic Editing in Picture Mode | |
63 | ||
64 | @findex picture-forward-column | |
65 | @findex picture-backward-column | |
66 | @findex picture-move-down | |
67 | @findex picture-move-up | |
68 | @cindex editing in Picture mode | |
69 | ||
70 | Most keys do the same thing in Picture mode that they usually do, but | |
71 | do it in a quarter-plane style. For example, @kbd{C-f} is rebound to | |
72 | run @code{picture-forward-column}, a command which moves point one | |
73 | column to the right, inserting a space if necessary so that the actual | |
74 | end of the line makes no difference. @kbd{C-b} is rebound to run | |
75 | @code{picture-backward-column}, which always moves point left one | |
76 | column, converting a tab to multiple spaces if necessary. @kbd{C-n} and | |
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 | |
79 | as necessary to make sure that point stays in exactly the same column. | |
80 | @kbd{C-e} runs @code{picture-end-of-line}, which moves to after the last | |
81 | nonblank character on the line. There is no need to change @kbd{C-a}, | |
82 | as the choice of screen model does not affect beginnings of | |
83 | lines. | |
84 | ||
85 | @findex picture-newline | |
86 | Insertion of text is adapted to the quarter-plane screen model | |
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87 | through the use of Overwrite mode |
88 | @iftex | |
89 | (@pxref{Minor Modes,,, emacs, the Emacs Manual}.) | |
90 | @end iftex | |
91 | @ifnottex | |
92 | (@pxref{Minor Modes}.) | |
93 | @end ifnottex | |
94 | Self-inserting characters replace existing text, column by column, | |
95 | rather than pushing existing text to the right. @key{RET} runs | |
96 | @code{picture-newline}, which just moves to the beginning of the | |
97 | following line so that new text will replace that line. | |
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98 | |
99 | @findex picture-backward-clear-column | |
100 | @findex picture-clear-column | |
101 | @findex picture-clear-line | |
102 | In Picture mode, the commands that normally delete or kill text, | |
103 | instead erase text (replacing it with spaces). @key{DEL} | |
104 | (@code{picture-backward-clear-column}) replaces the preceding | |
105 | character with a space rather than removing it; this moves point | |
106 | backwards. @kbd{C-d} (@code{picture-clear-column}) replaces the next | |
107 | character or characters with spaces, but does not move point. (If you | |
108 | want to clear characters to spaces and move forward over them, use | |
109 | @key{SPC}.) @kbd{C-k} (@code{picture-clear-line}) really kills the | |
110 | contents of lines, but does not delete the newlines from the buffer. | |
111 | ||
112 | @findex picture-open-line | |
113 | To do actual insertion, you must use special commands. @kbd{C-o} | |
114 | (@code{picture-open-line}) creates a blank line after the current | |
115 | line; it never splits a line. @kbd{C-M-o} (@code{split-line}) makes | |
116 | sense in Picture mode, so it is not changed. @kbd{C-j} | |
117 | (@code{picture-duplicate-line}) inserts another line with the same | |
118 | contents below the current line. | |
119 | ||
120 | @kindex C-c C-d @r{(Picture mode)} | |
121 | To do actual deletion in Picture mode, use @kbd{C-w}, @kbd{C-c C-d} | |
122 | (which is defined as @code{delete-char}, as @kbd{C-d} is in other | |
123 | modes), or one of the picture rectangle commands (@pxref{Rectangles in | |
124 | Picture}). | |
125 | ||
126 | @node Insert in Picture | |
127 | @section Controlling Motion after Insert | |
128 | ||
129 | @findex picture-movement-up | |
130 | @findex picture-movement-down | |
131 | @findex picture-movement-left | |
132 | @findex picture-movement-right | |
133 | @findex picture-movement-nw | |
134 | @findex picture-movement-ne | |
135 | @findex picture-movement-sw | |
136 | @findex picture-movement-se | |
137 | @kindex C-c < @r{(Picture mode)} | |
138 | @kindex C-c > @r{(Picture mode)} | |
139 | @kindex C-c ^ @r{(Picture mode)} | |
140 | @kindex C-c . @r{(Picture mode)} | |
141 | @kindex C-c ` @r{(Picture mode)} | |
142 | @kindex C-c ' @r{(Picture mode)} | |
143 | @kindex C-c / @r{(Picture mode)} | |
144 | @kindex C-c \ @r{(Picture mode)} | |
145 | Since ``self-inserting'' characters in Picture mode overwrite and move | |
146 | point, there is no essential restriction on how point should be moved. | |
147 | Normally point moves right, but you can specify any of the eight | |
148 | orthogonal or diagonal directions for motion after a ``self-inserting'' | |
149 | character. This is useful for drawing lines in the buffer. | |
150 | ||
151 | @table @kbd | |
152 | @item C-c < | |
153 | @itemx C-c @key{LEFT} | |
154 | Move left after insertion (@code{picture-movement-left}). | |
155 | @item C-c > | |
156 | @itemx C-c @key{RIGHT} | |
157 | Move right after insertion (@code{picture-movement-right}). | |
158 | @item C-c ^ | |
159 | @itemx C-c @key{UP} | |
160 | Move up after insertion (@code{picture-movement-up}). | |
161 | @item C-c . | |
162 | @itemx C-c @key{DOWN} | |
163 | Move down after insertion (@code{picture-movement-down}). | |
164 | @item C-c ` | |
165 | @itemx C-c @key{HOME} | |
166 | Move up and left (``northwest'') after insertion (@code{picture-movement-nw}). | |
167 | @item C-c ' | |
b5700de6 | 168 | @itemx C-c @key{prior} |
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169 | Move up and right (``northeast'') after insertion |
170 | (@code{picture-movement-ne}). | |
171 | @item C-c / | |
172 | @itemx C-c @key{END} | |
173 | Move down and left (``southwest'') after insertion | |
174 | @*(@code{picture-movement-sw}). | |
175 | @item C-c \ | |
b5700de6 | 176 | @itemx C-c @key{next} |
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177 | Move down and right (``southeast'') after insertion |
178 | @*(@code{picture-movement-se}). | |
179 | @end table | |
180 | ||
181 | @kindex C-c C-f @r{(Picture mode)} | |
182 | @kindex C-c C-b @r{(Picture mode)} | |
183 | @findex picture-motion | |
184 | @findex picture-motion-reverse | |
185 | Two motion commands move based on the current Picture insertion | |
186 | direction. The command @kbd{C-c C-f} (@code{picture-motion}) moves in the | |
187 | same direction as motion after ``insertion'' currently does, while @kbd{C-c | |
188 | C-b} (@code{picture-motion-reverse}) moves in the opposite direction. | |
189 | ||
190 | @node Tabs in Picture | |
191 | @section Picture Mode Tabs | |
192 | ||
193 | @kindex M-TAB @r{(Picture mode)} | |
194 | @findex picture-tab-search | |
195 | @vindex picture-tab-chars | |
196 | Two kinds of tab-like action are provided in Picture mode. Use | |
197 | @kbd{M-@key{TAB}} (@code{picture-tab-search}) for context-based tabbing. | |
198 | With no argument, it moves to a point underneath the next | |
199 | ``interesting'' character that follows whitespace in the previous | |
200 | nonblank line. ``Next'' here means ``appearing at a horizontal position | |
201 | greater than the one point starts out at.'' With an argument, as in | |
202 | @kbd{C-u M-@key{TAB}}, this command moves to the next such interesting | |
203 | character in the current line. @kbd{M-@key{TAB}} does not change the | |
204 | text; it only moves point. ``Interesting'' characters are defined by | |
205 | the variable @code{picture-tab-chars}, which should define a set of | |
206 | characters. The syntax for this variable is like the syntax used inside | |
207 | of @samp{[@dots{}]} in a regular expression---but without the @samp{[} | |
208 | and the @samp{]}. Its default value is @code{"!-~"}. | |
209 | ||
210 | @findex picture-tab | |
211 | @key{TAB} itself runs @code{picture-tab}, which operates based on the | |
212 | current tab stop settings; it is the Picture mode equivalent of | |
213 | @code{tab-to-tab-stop}. Normally it just moves point, but with a numeric | |
214 | argument it clears the text that it moves over. | |
215 | ||
216 | @kindex C-c TAB @r{(Picture mode)} | |
217 | @findex picture-set-tab-stops | |
218 | The context-based and tab-stop-based forms of tabbing are brought | |
219 | together by the command @kbd{C-c @key{TAB}} (@code{picture-set-tab-stops}). | |
220 | This command sets the tab stops to the positions which @kbd{M-@key{TAB}} | |
221 | would consider significant in the current line. The use of this command, | |
222 | together with @key{TAB}, can get the effect of context-based tabbing. But | |
223 | @kbd{M-@key{TAB}} is more convenient in the cases where it is sufficient. | |
224 | ||
225 | It may be convenient to prevent use of actual tab characters in | |
226 | pictures. For example, this prevents @kbd{C-x @key{TAB}} from messing | |
227 | up the picture. You can do this by setting the variable | |
228 | @code{indent-tabs-mode} to @code{nil}. | |
229 | ||
230 | @node Rectangles in Picture | |
231 | @section Picture Mode Rectangle Commands | |
232 | @cindex rectangles and Picture mode | |
233 | @cindex Picture mode and rectangles | |
234 | ||
235 | Picture mode defines commands for working on rectangular pieces of | |
236 | the text in ways that fit with the quarter-plane model. The standard | |
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237 | rectangle commands may also be useful. |
238 | @iftex | |
239 | @xref{Rectangles,,, emacs, the Emacs Manual}. | |
240 | @end iftex | |
241 | @ifnottex | |
242 | @xref{Rectangles}. | |
243 | @end ifnottex | |
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244 | |
245 | @table @kbd | |
246 | @item C-c C-k | |
247 | Clear out the region-rectangle with spaces | |
248 | (@code{picture-clear-rectangle}). With argument, delete the text. | |
249 | @item C-c C-w @var{r} | |
250 | Similar, but save rectangle contents in register @var{r} first | |
251 | (@code{picture-clear-rectangle-to-register}). | |
252 | @item C-c C-y | |
253 | Copy last killed rectangle into the buffer by overwriting, with upper | |
254 | left corner at point (@code{picture-yank-rectangle}). With argument, | |
255 | insert instead. | |
256 | @item C-c C-x @var{r} | |
257 | Similar, but use the rectangle in register @var{r} | |
258 | (@code{picture-yank-rectangle-from-register}). | |
259 | @end table | |
260 | ||
261 | @kindex C-c C-k @r{(Picture mode)} | |
262 | @kindex C-c C-w @r{(Picture mode)} | |
263 | @findex picture-clear-rectangle | |
264 | @findex picture-clear-rectangle-to-register | |
265 | The picture rectangle commands @kbd{C-c C-k} | |
266 | (@code{picture-clear-rectangle}) and @kbd{C-c C-w} | |
267 | (@code{picture-clear-rectangle-to-register}) differ from the standard | |
268 | rectangle commands in that they normally clear the rectangle instead of | |
269 | deleting it; this is analogous with the way @kbd{C-d} is changed in Picture | |
270 | mode. | |
271 | ||
272 | However, deletion of rectangles can be useful in Picture mode, so | |
273 | these commands delete the rectangle if given a numeric argument. | |
274 | @kbd{C-c C-k} either with or without a numeric argument saves the | |
275 | rectangle for @kbd{C-c C-y}. | |
276 | ||
277 | @kindex C-c C-y @r{(Picture mode)} | |
278 | @kindex C-c C-x @r{(Picture mode)} | |
279 | @findex picture-yank-rectangle | |
280 | @findex picture-yank-rectangle-from-register | |
281 | The Picture mode commands for yanking rectangles differ from the | |
282 | standard ones in that they overwrite instead of inserting. This is | |
283 | the same way that Picture mode insertion of other text differs from | |
284 | other modes. @kbd{C-c C-y} (@code{picture-yank-rectangle}) inserts | |
285 | (by overwriting) the rectangle that was most recently killed, while | |
286 | @kbd{C-c C-x} (@code{picture-yank-rectangle-from-register}) does | |
287 | likewise for the rectangle found in a specified register. | |
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288 | |
289 | @ignore | |
290 | arch-tag: 10e423ad-d896-42f2-a7e8-7018adeaf8c2 | |
291 | @end ignore |