| 1 | /* Window definitions for GNU Emacs. |
| 2 | Copyright (C) 1985, 1986, 1993, 1995 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GNU Emacs. |
| 5 | |
| 6 | GNU Emacs is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2, or (at your option) |
| 9 | any later version. |
| 10 | |
| 11 | GNU Emacs is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GNU Emacs; see the file COPYING. If not, write to |
| 18 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 19 | Boston, MA 02111-1307, USA. */ |
| 20 | |
| 21 | |
| 22 | /* Windows are allocated as if they were vectors, but then the |
| 23 | Lisp data type is changed to Lisp_Window. They are garbage |
| 24 | collected along with the vectors. |
| 25 | |
| 26 | All windows in use are arranged into a tree, with pointers up and down. |
| 27 | |
| 28 | Windows that are leaves of the tree are actually displayed |
| 29 | and show the contents of buffers. Windows that are not leaves |
| 30 | are used for representing the way groups of leaf windows are |
| 31 | arranged on the frame. Leaf windows never become non-leaves. |
| 32 | They are deleted only by calling delete-window on them (but |
| 33 | this can be done implicitly). Combination windows can be created |
| 34 | and deleted at any time. |
| 35 | |
| 36 | A leaf window has a non-nil buffer field, and also |
| 37 | has markers in its start and pointm fields. Non-leaf windows |
| 38 | have nil in these fields. |
| 39 | |
| 40 | Non-leaf windows are either vertical or horizontal combinations. |
| 41 | |
| 42 | A vertical combination window has children that are arranged on the frame |
| 43 | one above the next. Its vchild field points to the uppermost child. |
| 44 | The parent field of each of the children points to the vertical |
| 45 | combination window. The next field of each child points to the |
| 46 | child below it, or is nil for the lowest child. The prev field |
| 47 | of each child points to the child above it, or is nil for the |
| 48 | highest child. |
| 49 | |
| 50 | A horizontal combination window has children that are side by side. |
| 51 | Its hchild field points to the leftmost child. In each child |
| 52 | the next field points to the child to the right and the prev field |
| 53 | points to the child to the left. |
| 54 | |
| 55 | The children of a vertical combination window may be leaf windows |
| 56 | or horizontal combination windows. The children of a horizontal |
| 57 | combination window may be leaf windows or vertical combination windows. |
| 58 | |
| 59 | At the top of the tree are two windows which have nil as parent. |
| 60 | The second of these is minibuf_window. The first one manages all |
| 61 | the frame area that is not minibuffer, and is called the root window. |
| 62 | Different windows can be the root at different times; |
| 63 | initially the root window is a leaf window, but if more windows |
| 64 | are created then that leaf window ceases to be root and a newly |
| 65 | made combination window becomes root instead. |
| 66 | |
| 67 | In any case, on screens which have an ordinary window and a |
| 68 | minibuffer, prev of the minibuf window is the root window and next of |
| 69 | the root window is the minibuf window. On minibufferless screens or |
| 70 | minibuffer-only screens, the root window and the minibuffer window are |
| 71 | one and the same, so its prev and next members are nil. |
| 72 | |
| 73 | A dead window has its buffer, hchild, and vchild windows all nil. */ |
| 74 | |
| 75 | struct window |
| 76 | { |
| 77 | /* The first two fields are really the header of a vector */ |
| 78 | /* The window code does not refer to them. */ |
| 79 | EMACS_INT size; |
| 80 | struct Lisp_Vector *vec_next; |
| 81 | /* The frame this window is on. */ |
| 82 | Lisp_Object frame; |
| 83 | /* t if this window is a minibuffer window. */ |
| 84 | Lisp_Object mini_p; |
| 85 | /* Following child (to right or down) at same level of tree */ |
| 86 | Lisp_Object next; |
| 87 | /* Preceding child (to left or up) at same level of tree */ |
| 88 | Lisp_Object prev; |
| 89 | /* First child of this window. */ |
| 90 | /* vchild is used if this is a vertical combination, |
| 91 | hchild if this is a horizontal combination. */ |
| 92 | Lisp_Object hchild, vchild; |
| 93 | /* The window this one is a child of. */ |
| 94 | Lisp_Object parent; |
| 95 | /* The upper left corner coordinates of this window, |
| 96 | as integers relative to upper left corner of frame = 0, 0 */ |
| 97 | Lisp_Object left; |
| 98 | Lisp_Object top; |
| 99 | /* The size of the window */ |
| 100 | Lisp_Object height; |
| 101 | Lisp_Object width; |
| 102 | /* The buffer displayed in this window */ |
| 103 | /* Of the fields vchild, hchild and buffer, only one is non-nil. */ |
| 104 | Lisp_Object buffer; |
| 105 | /* A marker pointing to where in the text to start displaying */ |
| 106 | Lisp_Object start; |
| 107 | /* A marker pointing to where in the text point is in this window, |
| 108 | used only when the window is not selected. |
| 109 | This exists so that when multiple windows show one buffer |
| 110 | each one can have its own value of point. */ |
| 111 | Lisp_Object pointm; |
| 112 | /* Non-nil means next redisplay must use the value of start |
| 113 | set up for it in advance. Set by scrolling commands. */ |
| 114 | Lisp_Object force_start; |
| 115 | /* Non-nil means we have explicitly changed the value of start, |
| 116 | but that the next redisplay is not obliged to use the new value. */ |
| 117 | Lisp_Object optional_new_start; |
| 118 | /* Number of columns display within the window is scrolled to the left. */ |
| 119 | Lisp_Object hscroll; |
| 120 | /* Number saying how recently window was selected */ |
| 121 | Lisp_Object use_time; |
| 122 | /* Unique number of window assigned when it was created */ |
| 123 | Lisp_Object sequence_number; |
| 124 | /* No permanent meaning; used by save-window-excursion's bookkeeping */ |
| 125 | Lisp_Object temslot; |
| 126 | /* text.modified of displayed buffer as of last time display completed */ |
| 127 | Lisp_Object last_modified; |
| 128 | /* BUF_OVERLAY_MODIFIED of displayed buffer as of last complete update. */ |
| 129 | Lisp_Object last_overlay_modified; |
| 130 | /* Value of point at that time */ |
| 131 | Lisp_Object last_point; |
| 132 | /* Non-nil if the buffer was "modified" when the window |
| 133 | was last updated. */ |
| 134 | Lisp_Object last_had_star; |
| 135 | /* This window's vertical scroll bar. This field is only for use |
| 136 | by the window-system-dependent code which implements the |
| 137 | scroll bars; it can store anything it likes here. If this |
| 138 | window is newly created and we haven't displayed a scroll bar in |
| 139 | it yet, or if the frame doesn't have any scroll bars, this is nil. */ |
| 140 | Lisp_Object vertical_scroll_bar; |
| 141 | |
| 142 | /* The rest are currently not used or only half used */ |
| 143 | /* Frame coords of point at that time */ |
| 144 | Lisp_Object last_point_x; |
| 145 | Lisp_Object last_point_y; |
| 146 | /* Frame coords of mark as of last time display completed */ |
| 147 | /* May be nil if mark does not exist or was not on frame */ |
| 148 | Lisp_Object last_mark_x; |
| 149 | Lisp_Object last_mark_y; |
| 150 | /* Number of characters in buffer past bottom of window, |
| 151 | as of last redisplay that finished. */ |
| 152 | Lisp_Object window_end_pos; |
| 153 | /* t if window_end_pos is truly valid. |
| 154 | This is nil if nontrivial redisplay is preempted |
| 155 | since in that case the frame image that window_end_pos |
| 156 | did not get onto the frame. */ |
| 157 | Lisp_Object window_end_valid; |
| 158 | /* Vertical position (relative to window top) of that buffer position |
| 159 | of the first of those characters */ |
| 160 | Lisp_Object window_end_vpos; |
| 161 | /* Non-nil means must regenerate mode line of this window */ |
| 162 | Lisp_Object update_mode_line; |
| 163 | /* Non-nil means current value of `start' |
| 164 | was the beginning of a line when it was chosen. */ |
| 165 | Lisp_Object start_at_line_beg; |
| 166 | /* Display-table to use for displaying chars in this window. |
| 167 | Nil means use the buffer's own display-table. */ |
| 168 | Lisp_Object display_table; |
| 169 | /* Non-nil means window is marked as dedicated. */ |
| 170 | Lisp_Object dedicated; |
| 171 | /* Line number and position of a line somewhere above the |
| 172 | top of the screen. */ |
| 173 | /* If this field is nil, it means we don't have a base line. */ |
| 174 | Lisp_Object base_line_number; |
| 175 | /* If this field is nil, it means we don't have a base line. |
| 176 | If it is a buffer, it means don't display the line number |
| 177 | as long as the window shows that buffer. */ |
| 178 | Lisp_Object base_line_pos; |
| 179 | /* If we have highlighted the region (or any part of it), |
| 180 | this is the mark position that we used, as an integer. */ |
| 181 | Lisp_Object region_showing; |
| 182 | /* The column number currently displayed in this window's mode line, |
| 183 | or nil if column numbers are not being displayed. */ |
| 184 | Lisp_Object column_number_displayed; |
| 185 | /* If redisplay in this window goes beyond this buffer position, |
| 186 | must run the redisplay-end-trigger-hook. */ |
| 187 | Lisp_Object redisplay_end_trigger; |
| 188 | }; |
| 189 | |
| 190 | /* 1 if W is a minibuffer window. */ |
| 191 | |
| 192 | #define MINI_WINDOW_P(W) (!EQ ((W)->mini_p, Qnil)) |
| 193 | |
| 194 | /* Return the frame column at which the text in window W starts. |
| 195 | This is different from the `left' field because it does not include |
| 196 | a left-hand scroll bar if any. */ |
| 197 | |
| 198 | #define WINDOW_LEFT_MARGIN(W) \ |
| 199 | (XFASTINT ((W)->left) \ |
| 200 | + FRAME_LEFT_SCROLL_BAR_WIDTH (XFRAME (WINDOW_FRAME (W)))) |
| 201 | |
| 202 | /* Return the frame column before window W ends. |
| 203 | This includes a right-hand scroll bar, if any. */ |
| 204 | |
| 205 | #define WINDOW_RIGHT_EDGE(W) \ |
| 206 | (XFASTINT ((W)->left) + XFASTINT ((W)->width)) |
| 207 | |
| 208 | /* Return the frame column before which the text in window W ends. |
| 209 | This is different from WINDOW_RIGHT_EDGE because it does not include |
| 210 | a scroll bar or window-separating line on the right edge. */ |
| 211 | |
| 212 | #define WINDOW_RIGHT_MARGIN(W) \ |
| 213 | (WINDOW_RIGHT_EDGE (W) \ |
| 214 | - (! FRAME_HAS_VERTICAL_SCROLL_BARS (XFRAME (WINDOW_FRAME (W))) \ |
| 215 | ? 1 \ |
| 216 | : FRAME_HAS_VERTICAL_SCROLL_BARS_ON_RIGHT (XFRAME (WINDOW_FRAME (W))) \ |
| 217 | ? FRAME_SCROLL_BAR_COLS (XFRAME (WINDOW_FRAME (W))) \ |
| 218 | : 0)) |
| 219 | |
| 220 | /* 1 if window W takes up the full width of its frame. */ |
| 221 | |
| 222 | #define WINDOW_FULL_WIDTH_P(W) \ |
| 223 | (XFASTINT ((W)->width) == FRAME_WINDOW_WIDTH (XFRAME (WINDOW_FRAME (W)))) |
| 224 | |
| 225 | /* 1 if window W's has no other windows to its right in its frame. */ |
| 226 | |
| 227 | #define WINDOW_RIGHTMOST_P(W) \ |
| 228 | (WINDOW_RIGHT_EDGE (W) == FRAME_WINDOW_WIDTH (XFRAME (WINDOW_FRAME (W)))) |
| 229 | |
| 230 | /* This is the window in which the terminal's cursor should |
| 231 | be left when nothing is being done with it. This must |
| 232 | always be a leaf window, and its buffer is selected by |
| 233 | the top level editing loop at the end of each command. |
| 234 | |
| 235 | This value is always the same as |
| 236 | FRAME_SELECTED_WINDOW (selected_frame). */ |
| 237 | |
| 238 | extern Lisp_Object selected_window; |
| 239 | |
| 240 | /* This is a time stamp for window selection, so we can find the least |
| 241 | recently used window. Its only users are Fselect_window, |
| 242 | init_window_once, and make_frame. */ |
| 243 | |
| 244 | extern int window_select_count; |
| 245 | |
| 246 | /* The minibuffer window of the selected frame. |
| 247 | Note that you cannot test for minibufferness of an arbitrary window |
| 248 | by comparing against this; use the MINI_WINDOW_P macro instead. */ |
| 249 | |
| 250 | extern Lisp_Object minibuf_window; |
| 251 | |
| 252 | /* Non-nil => window to for C-M-v to scroll |
| 253 | when the minibuffer is selected. */ |
| 254 | extern Lisp_Object Vminibuf_scroll_window; |
| 255 | |
| 256 | /* nil or a symbol naming the window system |
| 257 | under which emacs is running |
| 258 | ('x is the only current possibility) */ |
| 259 | extern Lisp_Object Vwindow_system; |
| 260 | |
| 261 | /* Version number of X windows: 10, 11 or nil. */ |
| 262 | extern Lisp_Object Vwindow_system_version; |
| 263 | |
| 264 | /* Window that the mouse is over (nil if no mouse support). */ |
| 265 | extern Lisp_Object Vmouse_window; |
| 266 | |
| 267 | /* Last mouse-click event (nil if no mouse support). */ |
| 268 | extern Lisp_Object Vmouse_event; |
| 269 | |
| 270 | EXFUN (Fnext_window, 3); |
| 271 | EXFUN (Fselect_window, 1); |
| 272 | EXFUN (Fdisplay_buffer, 3); |
| 273 | EXFUN (Fset_window_buffer, 2); |
| 274 | extern Lisp_Object make_window P_ ((void)); |
| 275 | extern void delete_window P_ ((Lisp_Object)); |
| 276 | extern Lisp_Object window_from_coordinates P_ ((struct frame *, int, int, int *)); |
| 277 | EXFUN (Fwindow_dedicated_p, 1); |
| 278 | extern int window_height P_ ((Lisp_Object)); |
| 279 | extern int window_width P_ ((Lisp_Object)); |
| 280 | extern void set_window_height P_ ((Lisp_Object, int, int)); |
| 281 | extern void set_window_width P_ ((Lisp_Object, int, int)); |
| 282 | extern void change_window_height P_ ((int, int)); |
| 283 | extern void delete_all_subwindows P_ ((struct window *)); |
| 284 | |
| 285 | /* Prompt to display in front of the minibuffer contents. */ |
| 286 | extern Lisp_Object minibuf_prompt; |
| 287 | |
| 288 | /* The visual width of the above. */ |
| 289 | extern int minibuf_prompt_width; |
| 290 | |
| 291 | /* Message to display instead of minibuffer contents. |
| 292 | This is what the functions error and message make, |
| 293 | and command echoing uses it as well. It overrides the |
| 294 | minibuf_prompt as well as the buffer. */ |
| 295 | extern char *echo_area_glyphs; |
| 296 | |
| 297 | /* This is the length of the message in echo_area_glyphs. */ |
| 298 | extern int echo_area_glyphs_length; |
| 299 | |
| 300 | /* Value of echo_area_glyphs when it was last acted on. |
| 301 | If this is nonzero, there is a message on the frame |
| 302 | in the minibuffer and it should be erased as soon |
| 303 | as it is no longer requested to appear. */ |
| 304 | extern char *previous_echo_glyphs; |
| 305 | |
| 306 | /* This is the window where the echo area message was displayed. |
| 307 | It is always a minibuffer window, but it may not be the |
| 308 | same window currently active as a minibuffer. */ |
| 309 | extern Lisp_Object echo_area_window; |
| 310 | |
| 311 | /* Depth in recursive edits. */ |
| 312 | extern int command_loop_level; |
| 313 | |
| 314 | /* Depth in minibuffer invocations. */ |
| 315 | extern int minibuf_level; |
| 316 | |
| 317 | /* true iff we should redraw the mode lines on the next redisplay. */ |
| 318 | extern int update_mode_lines; |
| 319 | |
| 320 | /* Minimum value of GPT - BEG since last redisplay that finished. */ |
| 321 | |
| 322 | extern int beg_unchanged; |
| 323 | |
| 324 | /* Minimum value of Z - GPT since last redisplay that finished. */ |
| 325 | |
| 326 | extern int end_unchanged; |
| 327 | |
| 328 | /* MODIFF as of last redisplay that finished; |
| 329 | if it matches MODIFF, beg_unchanged and end_unchanged |
| 330 | contain no useful information. */ |
| 331 | extern int unchanged_modified; |
| 332 | |
| 333 | /* BUF_OVERLAY_MODIFF of current buffer, as of last redisplay that finished; |
| 334 | if it matches BUF_OVERLAY_MODIFF, beg_unchanged and end_unchanged |
| 335 | contain no useful information. */ |
| 336 | extern int overlay_unchanged_modified; |
| 337 | |
| 338 | /* Nonzero if BEGV - BEG or Z - ZV of current buffer has changed |
| 339 | since last redisplay that finished. */ |
| 340 | extern int clip_changed; |
| 341 | |
| 342 | /* Nonzero if window sizes or contents have changed |
| 343 | since last redisplay that finished */ |
| 344 | extern int windows_or_buffers_changed; |
| 345 | |
| 346 | /* Number of windows displaying the selected buffer. |
| 347 | Normally this is 1, but it can be more. */ |
| 348 | extern int buffer_shared; |
| 349 | |
| 350 | /* If *ROWS or *COLS are too small a size for FRAME, set them to the |
| 351 | minimum allowable size. */ |
| 352 | extern void check_frame_size P_ ((struct frame *frame, int *rows, int *cols)); |