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1 | @c This is part of the Emacs manual. |
2 | @c Copyright (C) 1985, 86, 87, 93, 94, 95, 1997 Free Software Foundation, Inc. | |
3 | @c See file emacs.texi for copying conditions. | |
4 | @node Picture, Sending Mail, Abbrevs, Top | |
5 | @chapter Editing Pictures | |
6 | @cindex pictures | |
7 | @cindex making pictures out of text characters | |
8 | @findex edit-picture | |
9 | ||
10 | To edit a picture made out of text characters (for example, a picture | |
11 | of the division of a register into fields, as a comment in a program), | |
12 | use the command @kbd{M-x edit-picture} to enter Picture mode. | |
13 | ||
14 | In Picture mode, editing is based on the @dfn{quarter-plane} model of | |
15 | text, according to which the text characters lie studded on an area that | |
16 | stretches infinitely far to the right and downward. The concept of the end | |
17 | of a line does not exist in this model; the most you can say is where the | |
18 | last nonblank character on the line is found. | |
19 | ||
20 | Of course, Emacs really always considers text as a sequence of | |
21 | characters, and lines really do have ends. But Picture mode replaces | |
22 | the most frequently-used commands with variants that simulate the | |
23 | quarter-plane model of text. They do this by inserting spaces or by | |
24 | converting tabs to spaces. | |
25 | ||
26 | Most of the basic editing commands of Emacs are redefined by Picture mode | |
27 | to do essentially the same thing but in a quarter-plane way. In addition, | |
28 | Picture mode defines various keys starting with the @kbd{C-c} prefix to | |
29 | run special picture editing commands. | |
30 | ||
31 | One of these keys, @kbd{C-c C-c}, is pretty important. Often a | |
32 | picture is part of a larger file that is usually edited in some other | |
33 | major mode. @kbd{M-x edit-picture} records the name of the previous | |
34 | major mode so you can use the @kbd{C-c C-c} command | |
35 | (@code{picture-mode-exit}) later to go back to that mode. @kbd{C-c C-c} | |
36 | also deletes spaces from the ends of lines, unless given a numeric | |
37 | argument. | |
38 | ||
39 | The special commands of Picture mode all work in other modes (provided | |
40 | the @file{picture} library is loaded), but are not bound to keys except | |
41 | in Picture mode. The descriptions below talk of moving ``one column'' | |
42 | and so on, but all the picture mode commands handle numeric arguments as | |
43 | their normal equivalents do. | |
44 | ||
45 | @vindex picture-mode-hook | |
46 | Turning on Picture mode runs the hook @code{picture-mode-hook} | |
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47 | (@pxref{Hooks}). Additional extensions to Picture mode can be found |
48 | in @file{artist.el}. | |
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49 | |
50 | @menu | |
51 | * Basic Picture:: Basic concepts and simple commands of Picture Mode. | |
52 | * Insert in Picture:: Controlling direction of cursor motion | |
53 | after "self-inserting" characters. | |
54 | * Tabs in Picture:: Various features for tab stops and indentation. | |
55 | * Rectangles in Picture:: Clearing and superimposing rectangles. | |
56 | @end menu | |
57 | ||
58 | @node Basic Picture, Insert in Picture, Picture, Picture | |
59 | @section Basic Editing in Picture Mode | |
60 | ||
61 | @findex picture-forward-column | |
62 | @findex picture-backward-column | |
63 | @findex picture-move-down | |
64 | @findex picture-move-up | |
65 | @cindex editing in Picture mode | |
66 | ||
67 | Most keys do the same thing in Picture mode that they usually do, but | |
68 | do it in a quarter-plane style. For example, @kbd{C-f} is rebound to | |
69 | run @code{picture-forward-column}, a command which moves point one | |
70 | column to the right, inserting a space if necessary so that the actual | |
71 | end of the line makes no difference. @kbd{C-b} is rebound to run | |
72 | @code{picture-backward-column}, which always moves point left one | |
73 | column, converting a tab to multiple spaces if necessary. @kbd{C-n} and | |
74 | @kbd{C-p} are rebound to run @code{picture-move-down} and | |
75 | @code{picture-move-up}, which can either insert spaces or convert tabs | |
76 | as necessary to make sure that point stays in exactly the same column. | |
77 | @kbd{C-e} runs @code{picture-end-of-line}, which moves to after the last | |
78 | nonblank character on the line. There is no need to change @kbd{C-a}, | |
79 | as the choice of screen model does not affect beginnings of | |
80 | lines. | |
81 | ||
82 | @findex picture-newline | |
83 | Insertion of text is adapted to the quarter-plane screen model through | |
84 | the use of Overwrite mode (@pxref{Minor Modes}). Self-inserting characters | |
85 | replace existing text, column by column, rather than pushing existing text | |
86 | to the right. @key{RET} runs @code{picture-newline}, which just moves to | |
87 | the beginning of the following line so that new text will replace that | |
88 | line. | |
89 | ||
90 | @findex picture-backward-clear-column | |
91 | @findex picture-clear-column | |
92 | @findex picture-clear-line | |
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93 | In Picture mode, the commands that normally delete or kill text, |
94 | instead erase text (replacing it with spaces). @key{DEL} | |
95 | (@code{picture-backward-clear-column}) replaces the preceding | |
96 | character with a space rather than removing it; this moves point | |
97 | backwards. @kbd{C-d} (@code{picture-clear-column}) replaces the next | |
98 | character or characters with spaces, but does not move point. (If you | |
99 | want to clear characters to spaces and move forward over them, use | |
6bf7aab6 | 100 | @key{SPC}.) @kbd{C-k} (@code{picture-clear-line}) really kills the |
61ff7bed | 101 | contents of lines, but does not delete the newlines from the buffer. |
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102 | |
103 | @findex picture-open-line | |
104 | To do actual insertion, you must use special commands. @kbd{C-o} | |
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105 | (@code{picture-open-line}) creates a blank line after the current |
106 | line; it never splits a line. @kbd{C-M-o} (@code{split-line}) makes | |
107 | sense in Picture mode, so it is not changed. @kbd{C-j} | |
108 | (@code{picture-duplicate-line}) inserts another line with the same | |
109 | contents below the current line. | |
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110 | |
111 | @kindex C-c C-d @r{(Picture mode)} | |
112 | To do actual deletion in Picture mode, use @kbd{C-w}, @kbd{C-c C-d} | |
113 | (which is defined as @code{delete-char}, as @kbd{C-d} is in other | |
114 | modes), or one of the picture rectangle commands (@pxref{Rectangles in | |
115 | Picture}). | |
116 | ||
117 | @node Insert in Picture, Tabs in Picture, Basic Picture, Picture | |
118 | @section Controlling Motion after Insert | |
119 | ||
120 | @findex picture-movement-up | |
121 | @findex picture-movement-down | |
122 | @findex picture-movement-left | |
123 | @findex picture-movement-right | |
124 | @findex picture-movement-nw | |
125 | @findex picture-movement-ne | |
126 | @findex picture-movement-sw | |
127 | @findex picture-movement-se | |
128 | @kindex C-c < @r{(Picture mode)} | |
129 | @kindex C-c > @r{(Picture mode)} | |
130 | @kindex C-c ^ @r{(Picture mode)} | |
131 | @kindex C-c . @r{(Picture mode)} | |
132 | @kindex C-c ` @r{(Picture mode)} | |
133 | @kindex C-c ' @r{(Picture mode)} | |
134 | @kindex C-c / @r{(Picture mode)} | |
135 | @kindex C-c \ @r{(Picture mode)} | |
136 | Since ``self-inserting'' characters in Picture mode overwrite and move | |
137 | point, there is no essential restriction on how point should be moved. | |
138 | Normally point moves right, but you can specify any of the eight | |
139 | orthogonal or diagonal directions for motion after a ``self-inserting'' | |
140 | character. This is useful for drawing lines in the buffer. | |
141 | ||
142 | @table @kbd | |
143 | @item C-c < | |
61ff7bed | 144 | @itemx C-c @key{LEFT} |
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145 | Move left after insertion (@code{picture-movement-left}). |
146 | @item C-c > | |
61ff7bed | 147 | @itemx C-c @key{RIGHT} |
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148 | Move right after insertion (@code{picture-movement-right}). |
149 | @item C-c ^ | |
61ff7bed | 150 | @itemx C-c @key{UP} |
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151 | Move up after insertion (@code{picture-movement-up}). |
152 | @item C-c . | |
61ff7bed | 153 | @itemx C-c @key{DOWN} |
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154 | Move down after insertion (@code{picture-movement-down}). |
155 | @item C-c ` | |
61ff7bed | 156 | @itemx C-c @key{HOME} |
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157 | Move up and left (``northwest'') after insertion (@code{picture-movement-nw}). |
158 | @item C-c ' | |
61ff7bed | 159 | @itemx C-c @key{PAGEUP} |
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160 | Move up and right (``northeast'') after insertion |
161 | (@code{picture-movement-ne}). | |
162 | @item C-c / | |
61ff7bed | 163 | @itemx C-c @key{END} |
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164 | Move down and left (``southwest'') after insertion |
165 | @*(@code{picture-movement-sw}). | |
166 | @item C-c \ | |
61ff7bed | 167 | @itemx C-c @key{PAGEDOWN} |
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168 | Move down and right (``southeast'') after insertion |
169 | @*(@code{picture-movement-se}). | |
170 | @end table | |
171 | ||
172 | @kindex C-c C-f @r{(Picture mode)} | |
173 | @kindex C-c C-b @r{(Picture mode)} | |
174 | @findex picture-motion | |
175 | @findex picture-motion-reverse | |
176 | Two motion commands move based on the current Picture insertion | |
177 | direction. The command @kbd{C-c C-f} (@code{picture-motion}) moves in the | |
178 | same direction as motion after ``insertion'' currently does, while @kbd{C-c | |
179 | C-b} (@code{picture-motion-reverse}) moves in the opposite direction. | |
180 | ||
181 | @node Tabs in Picture, Rectangles in Picture, Insert in Picture, Picture | |
182 | @section Picture Mode Tabs | |
183 | ||
184 | @kindex M-TAB @r{(Picture mode)} | |
185 | @findex picture-tab-search | |
186 | @vindex picture-tab-chars | |
187 | Two kinds of tab-like action are provided in Picture mode. Use | |
188 | @kbd{M-@key{TAB}} (@code{picture-tab-search}) for context-based tabbing. | |
189 | With no argument, it moves to a point underneath the next | |
190 | ``interesting'' character that follows whitespace in the previous | |
191 | nonblank line. ``Next'' here means ``appearing at a horizontal position | |
192 | greater than the one point starts out at.'' With an argument, as in | |
193 | @kbd{C-u M-@key{TAB}}, this command moves to the next such interesting | |
194 | character in the current line. @kbd{M-@key{TAB}} does not change the | |
195 | text; it only moves point. ``Interesting'' characters are defined by | |
196 | the variable @code{picture-tab-chars}, which should define a set of | |
197 | characters. The syntax for this variable is like the syntax used inside | |
198 | of @samp{[@dots{}]} in a regular expression---but without the @samp{[} | |
199 | and the @samp{]}. Its default value is @code{"!-~"}. | |
200 | ||
201 | @findex picture-tab | |
202 | @key{TAB} itself runs @code{picture-tab}, which operates based on the | |
203 | current tab stop settings; it is the Picture mode equivalent of | |
204 | @code{tab-to-tab-stop}. Normally it just moves point, but with a numeric | |
205 | argument it clears the text that it moves over. | |
206 | ||
207 | @kindex C-c TAB @r{(Picture mode)} | |
208 | @findex picture-set-tab-stops | |
209 | The context-based and tab-stop-based forms of tabbing are brought | |
210 | together by the command @kbd{C-c @key{TAB}} (@code{picture-set-tab-stops}). | |
211 | This command sets the tab stops to the positions which @kbd{M-@key{TAB}} | |
212 | would consider significant in the current line. The use of this command, | |
213 | together with @key{TAB}, can get the effect of context-based tabbing. But | |
214 | @kbd{M-@key{TAB}} is more convenient in the cases where it is sufficient. | |
215 | ||
216 | It may be convenient to prevent use of actual tab characters in | |
217 | pictures. For example, this prevents @kbd{C-x @key{TAB}} from messing | |
218 | up the picture. You can do this by setting the variable | |
219 | @code{indent-tabs-mode} to @code{nil}. @xref{Just Spaces}. | |
220 | ||
221 | @node Rectangles in Picture,, Tabs in Picture, Picture | |
222 | @section Picture Mode Rectangle Commands | |
223 | @cindex rectangles and Picture mode | |
224 | @cindex Picture mode and rectangles | |
225 | ||
226 | Picture mode defines commands for working on rectangular pieces of the | |
227 | text in ways that fit with the quarter-plane model. The standard rectangle | |
228 | commands may also be useful (@pxref{Rectangles}). | |
229 | ||
230 | @table @kbd | |
231 | @item C-c C-k | |
232 | Clear out the region-rectangle with spaces | |
233 | (@code{picture-clear-rectangle}). With argument, delete the text. | |
234 | @item C-c C-w @var{r} | |
58fa012d | 235 | Similar, but save rectangle contents in register @var{r} first |
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236 | (@code{picture-clear-rectangle-to-register}). |
237 | @item C-c C-y | |
238 | Copy last killed rectangle into the buffer by overwriting, with upper | |
239 | left corner at point (@code{picture-yank-rectangle}). With argument, | |
240 | insert instead. | |
241 | @item C-c C-x @var{r} | |
242 | Similar, but use the rectangle in register @var{r} | |
243 | (@code{picture-yank-rectangle-from-register}). | |
244 | @end table | |
245 | ||
246 | @kindex C-c C-k @r{(Picture mode)} | |
247 | @kindex C-c C-w @r{(Picture mode)} | |
248 | @findex picture-clear-rectangle | |
249 | @findex picture-clear-rectangle-to-register | |
250 | The picture rectangle commands @kbd{C-c C-k} | |
251 | (@code{picture-clear-rectangle}) and @kbd{C-c C-w} | |
252 | (@code{picture-clear-rectangle-to-register}) differ from the standard | |
253 | rectangle commands in that they normally clear the rectangle instead of | |
254 | deleting it; this is analogous with the way @kbd{C-d} is changed in Picture | |
255 | mode. | |
256 | ||
257 | However, deletion of rectangles can be useful in Picture mode, so | |
258 | these commands delete the rectangle if given a numeric argument. | |
259 | @kbd{C-c C-k} either with or without a numeric argument saves the | |
260 | rectangle for @kbd{C-c C-y}. | |
261 | ||
262 | @kindex C-c C-y @r{(Picture mode)} | |
263 | @kindex C-c C-x @r{(Picture mode)} | |
264 | @findex picture-yank-rectangle | |
265 | @findex picture-yank-rectangle-from-register | |
266 | The Picture mode commands for yanking rectangles differ from the | |
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267 | standard ones in that they overwrite instead of inserting. This is |
268 | the same way that Picture mode insertion of other text differs from | |
269 | other modes. @kbd{C-c C-y} (@code{picture-yank-rectangle}) inserts | |
270 | (by overwriting) the rectangle that was most recently killed, while | |
271 | @kbd{C-c C-x} (@code{picture-yank-rectangle-from-register}) does | |
272 | likewise for the rectangle found in a specified register. | |
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273 | |
274 | @ignore | |
275 | arch-tag: b7589747-683c-4f40-aed8-1b10403cb666 | |
276 | @end ignore |