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1 @c -*-texinfo-*-
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2 @c This is part of the XEmacs Lisp Reference Manual.
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3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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4 @c See the file lispref.texi for copying conditions.
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5 @setfilename ../../info/windows.info
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6 @node Windows, Frames, Buffers, Top
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7 @chapter Windows
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8
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9 This chapter describes most of the functions and variables related to
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10 Emacs windows. See @ref{Display}, for information on how text is
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11 displayed in windows.
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12
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13 @menu
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14 * Basic Windows:: Basic information on using windows.
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15 * Splitting Windows:: Splitting one window into two windows.
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16 * Deleting Windows:: Deleting a window gives its space to other windows.
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17 * Selecting Windows:: The selected window is the one that you edit in.
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18 * Cyclic Window Ordering:: Moving around the existing windows.
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19 * Buffers and Windows:: Each window displays the contents of a buffer.
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20 * Displaying Buffers:: Higher-lever functions for displaying a buffer
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21 and choosing a window for it.
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22 * Choosing Window:: How to choose a window for displaying a buffer.
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23 * Window Point:: Each window has its own location of point.
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24 * Window Start:: The display-start position controls which text
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25 is on-screen in the window.
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26 * Vertical Scrolling:: Moving text up and down in the window.
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27 * Horizontal Scrolling:: Moving text sideways on the window.
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28 * Size of Window:: Accessing the size of a window.
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29 * Position of Window:: Accessing the position of a window.
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30 * Resizing Windows:: Changing the size of a window.
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31 * Window Configurations:: Saving and restoring the state of the screen.
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32 @end menu
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33
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34 @node Basic Windows
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35 @section Basic Concepts of Emacs Windows
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36 @cindex window
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37 @cindex selected window
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38
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39 A @dfn{window} in XEmacs is the physical area of the screen in which a
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40 buffer is displayed. The term is also used to refer to a Lisp object that
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41 represents that screen area in XEmacs Lisp. It should be
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42 clear from the context which is meant.
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43
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44 XEmacs groups windows into frames. A frame represents an area of
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45 screen available for XEmacs to use. Each frame always contains at least
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46 one window, but you can subdivide it vertically or horizontally into
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47 multiple nonoverlapping Emacs windows.
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48
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49 In each frame, at any time, one and only one window is designated as
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50 @dfn{selected within the frame}. The frame's cursor appears in that
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51 window. At ant time, one frame is the selected frame; and the window
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52 selected within that frame is @dfn{the selected window}. The selected
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53 window's buffer is usually the current buffer (except when
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54 @code{set-buffer} has been used). @xref{Current Buffer}.
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55
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56 For practical purposes, a window exists only while it is displayed in
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57 a frame. Once removed from the frame, the window is effectively deleted
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58 and should not be used, @emph{even though there may still be references
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59 to it} from other Lisp objects. Restoring a saved window configuration
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60 is the only way for a window no longer on the screen to come back to
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61 life. (@xref{Deleting Windows}.)
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62
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63 Each window has the following attributes:
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64
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65 @itemize @bullet
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66 @item
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67 containing frame
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68
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69 @item
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70 window height
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71
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72 @item
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73 window width
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74
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75 @item
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76 window edges with respect to the frame or screen
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77
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78 @item
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79 the buffer it displays
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80
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81 @item
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82 position within the buffer at the upper left of the window
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83
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84 @item
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85 amount of horizontal scrolling, in columns
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86
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87 @item
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88 point
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89
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90 @item
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91 the mark
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92
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93 @item
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94 how recently the window was selected
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95 @end itemize
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96
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97 @cindex multiple windows
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98 Users create multiple windows so they can look at several buffers at
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99 once. Lisp libraries use multiple windows for a variety of reasons, but
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100 most often to display related information. In Rmail, for example, you
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101 can move through a summary buffer in one window while the other window
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102 shows messages one at a time as they are reached.
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103
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104 The meaning of ``window'' in XEmacs is similar to what it means in the
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105 context of general-purpose window systems such as X, but not identical.
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106 The X Window System places X windows on the screen; XEmacs uses one or
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107 more X windows as frames, and subdivides them into
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108 Emacs windows. When you use XEmacs on a character-only terminal, XEmacs
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109 treats the whole terminal screen as one frame.
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110
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111 @cindex terminal frame
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112 @cindex frame of terminal
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113 @cindex tiled windows
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114 Most window systems support arbitrarily located overlapping windows.
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115 In contrast, Emacs windows are @dfn{tiled}; they never overlap, and
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116 together they fill the whole screen or frame. Because of the way
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117 in which XEmacs creates new windows and resizes them, you can't create
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118 every conceivable tiling of windows on an Emacs frame. @xref{Splitting
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119 Windows}, and @ref{Size of Window}.
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120
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121 @xref{Display}, for information on how the contents of the
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122 window's buffer are displayed in the window.
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123
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124 @defun windowp object
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125 This function returns @code{t} if @var{object} is a window.
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126 @end defun
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127
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128 @node Splitting Windows
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129 @section Splitting Windows
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130 @cindex splitting windows
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131 @cindex window splitting
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132
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133 The functions described here are the primitives used to split a window
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134 into two windows. Two higher level functions sometimes split a window,
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135 but not always: @code{pop-to-buffer} and @code{display-buffer}
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136 (@pxref{Displaying Buffers}).
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137
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138 The functions described here do not accept a buffer as an argument.
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139 The two ``halves'' of the split window initially display the same buffer
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140 previously visible in the window that was split.
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141
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142 @defun one-window-p &optional no-mini all-frames
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143 This function returns non-@code{nil} if there is only one window. The
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144 argument @var{no-mini}, if non-@code{nil}, means don't count the
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145 minibuffer even if it is active; otherwise, the minibuffer window is
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146 included, if active, in the total number of windows which is compared
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147 against one.
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148
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149 The argument @var{all-frame} controls which set of windows are
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150 counted.
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151 @itemize @bullet
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152 @item
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153 If it is @code{nil} or omitted, then count only the selected frame, plus
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154 the minibuffer it uses (which may be on another frame).
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155 @item
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156 If it is @code{t}, then windows on all frames that currently exist
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157 (including invisible and iconified frames) are counted.
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158 @item
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159 If it is the symbol @code{visible}, then windows on all visible frames
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160 are counted.
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161 @item
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162 If it is the number 0, then windows on all visible and iconified frames
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163 are counted.
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164 @item
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165 If it is any other value, then precisely the windows in @var{window}'s
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166 frame are counted, excluding the minibuffer in use if it lies in
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167 some other frame.
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168 @end itemize
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169 @end defun
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170
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171 @deffn Command split-window &optional window size horizontal
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172 This function splits @var{window} into two windows. The original
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173 window @var{window} remains the selected window, but occupies only
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174 part of its former screen area. The rest is occupied by a newly created
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175 window which is returned as the value of this function.
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176
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177 If @var{horizontal} is non-@code{nil}, then @var{window} splits into
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178 two side by side windows. The original window @var{window} keeps the
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179 leftmost @var{size} columns, and gives the rest of the columns to the
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180 new window. Otherwise, it splits into windows one above the other, and
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181 @var{window} keeps the upper @var{size} lines and gives the rest of the
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182 lines to the new window. The original window is therefore the
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183 left-hand or upper of the two, and the new window is the right-hand or
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184 lower.
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185
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186 If @var{window} is omitted or @code{nil}, then the selected window is
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187 split. If @var{size} is omitted or @code{nil}, then @var{window} is
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188 divided evenly into two parts. (If there is an odd line, it is
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189 allocated to the new window.) When @code{split-window} is called
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190 interactively, all its arguments are @code{nil}.
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191
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192 The following example starts with one window on a frame that is 50
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193 lines high by 80 columns wide; then the window is split.
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194
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195 @smallexample
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196 @group
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197 (setq w (selected-window))
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198 @result{} #<window 8 on windows.texi>
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199 (window-edges) ; @r{Edges in order:}
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200 @result{} (0 0 80 50) ; @r{left--top--right--bottom}
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201 @end group
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202
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203 @group
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204 ;; @r{Returns window created}
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205 (setq w2 (split-window w 15))
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206 @result{} #<window 28 on windows.texi>
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207 @end group
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208 @group
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209 (window-edges w2)
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210 @result{} (0 15 80 50) ; @r{Bottom window;}
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211 ; @r{top is line 15}
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212 @end group
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213 @group
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214 (window-edges w)
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215 @result{} (0 0 80 15) ; @r{Top window}
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216 @end group
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217 @end smallexample
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218
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219 The frame looks like this:
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220
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221 @smallexample
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222 @group
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223 __________
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224 | | line 0
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225 | w |
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226 |__________|
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227 | | line 15
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228 | w2 |
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229 |__________|
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230 line 50
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231 column 0 column 80
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232 @end group
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233 @end smallexample
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234
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235 Next, the top window is split horizontally:
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236
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237 @smallexample
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238 @group
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239 (setq w3 (split-window w 35 t))
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240 @result{} #<window 32 on windows.texi>
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241 @end group
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242 @group
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243 (window-edges w3)
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244 @result{} (35 0 80 15) ; @r{Left edge at column 35}
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245 @end group
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246 @group
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247 (window-edges w)
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248 @result{} (0 0 35 15) ; @r{Right edge at column 35}
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249 @end group
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250 @group
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251 (window-edges w2)
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252 @result{} (0 15 80 50) ; @r{Bottom window unchanged}
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253 @end group
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254 @end smallexample
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255
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256 @need 3000
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257 Now, the screen looks like this:
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258
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259 @smallexample
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260 @group
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261 column 35
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262 __________
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263 | | | line 0
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264 | w | w3 |
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265 |___|______|
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266 | | line 15
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267 | w2 |
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268 |__________|
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269 line 50
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270 column 0 column 80
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271 @end group
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272 @end smallexample
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273
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274 Normally, Emacs indicates the border between two side-by-side windows
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275 with a scroll bar (@pxref{X Frame Properties,Scroll Bars}) or @samp{|}
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276 characters. The display table can specify alternative border
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277 characters; see @ref{Display Tables}.
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278 @end deffn
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279
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280 @deffn Command split-window-vertically &optional size
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281 This function splits the selected window into two windows, one above
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282 the other, leaving the selected window with @var{size} lines.
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283
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284 This function is simply an interface to @code{split-windows}.
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285 Here is the complete function definition for it:
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286
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287 @smallexample
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288 @group
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289 (defun split-window-vertically (&optional arg)
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290 "Split current window into two windows, one above the other."
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291 (interactive "P")
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292 (split-window nil (and arg (prefix-numeric-value arg))))
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293 @end group
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294 @end smallexample
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295 @end deffn
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296
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297 @deffn Command split-window-horizontally &optional size
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298 This function splits the selected window into two windows
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299 side-by-side, leaving the selected window with @var{size} columns.
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300
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301 This function is simply an interface to @code{split-windows}. Here is
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302 the complete definition for @code{split-window-horizontally} (except for
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303 part of the documentation string):
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304
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305 @smallexample
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306 @group
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307 (defun split-window-horizontally (&optional arg)
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308 "Split selected window into two windows, side by side..."
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309 (interactive "P")
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310 (split-window nil (and arg (prefix-numeric-value arg)) t))
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311 @end group
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312 @end smallexample
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313 @end deffn
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314
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315 @defun one-window-p &optional no-mini all-frames
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316 This function returns non-@code{nil} if there is only one window. The
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317 argument @var{no-mini}, if non-@code{nil}, means don't count the
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318 minibuffer even if it is active; otherwise, the minibuffer window is
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319 included, if active, in the total number of windows, which is compared
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320 against one.
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321
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322 The argument @var{all-frames} specifies which frames to consider. Here
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323 are the possible values and their meanings:
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324
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325 @table @asis
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326 @item @code{nil}
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327 Count the windows in the selected frame, plus the minibuffer used
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328 by that frame even if it lies in some other frame.
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329
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330 @item @code{t}
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331 Count all windows in all existing frames.
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332
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333 @item @code{visible}
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334 Count all windows in all visible frames.
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335
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336 @item 0
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337 Count all windows in all visible or iconified frames.
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338
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339 @item anything else
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340 Count precisely the windows in the selected frame, and no others.
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341 @end table
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342 @end defun
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343
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344 @node Deleting Windows
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345 @section Deleting Windows
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346 @cindex deleting windows
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347
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348 A window remains visible on its frame unless you @dfn{delete} it by
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349 calling certain functions that delete windows. A deleted window cannot
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350 appear on the screen, but continues to exist as a Lisp object until
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351 there are no references to it. There is no way to cancel the deletion
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352 of a window aside from restoring a saved window configuration
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353 (@pxref{Window Configurations}). Restoring a window configuration also
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354 deletes any windows that aren't part of that configuration.
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355
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356 When you delete a window, the space it took up is given to one
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357 adjacent sibling. (In Emacs version 18, the space was divided evenly
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358 among all the siblings.)
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359
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360 @c Emacs 19 feature
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361 @defun window-live-p window
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362 This function returns @code{nil} if @var{window} is deleted, and
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363 @code{t} otherwise.
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364
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365 @strong{Warning:} Erroneous information or fatal errors may result from
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366 using a deleted window as if it were live.
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367 @end defun
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368
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369 @deffn Command delete-window &optional window
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370 This function removes @var{window} from the display. If @var{window}
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371 is omitted, then the selected window is deleted. An error is signaled
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372 if there is only one window when @code{delete-window} is called.
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373
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374 This function returns @code{nil}.
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375
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376 When @code{delete-window} is called interactively, @var{window}
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377 defaults to the selected window.
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378 @end deffn
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379
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380 @deffn Command delete-other-windows &optional window
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381 This function makes @var{window} the only window on its frame, by
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382 deleting the other windows in that frame. If @var{window} is omitted or
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383 @code{nil}, then the selected window is used by default.
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384
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385 The result is @code{nil}.
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386 @end deffn
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387
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388 @deffn Command delete-windows-on buffer &optional frame
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389 This function deletes all windows showing @var{buffer}. If there are
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390 no windows showing @var{buffer}, it does nothing.
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391
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392 @code{delete-windows-on} operates frame by frame. If a frame has
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393 several windows showing different buffers, then those showing
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394 @var{buffer} are removed, and the others expand to fill the space. If
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395 all windows in some frame are showing @var{buffer} (including the case
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396 where there is only one window), then the frame reverts to having a
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397 single window showing another buffer chosen with @code{other-buffer}.
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398 @xref{The Buffer List}.
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399
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400 The argument @var{frame} controls which frames to operate on:
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401
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402 @itemize @bullet
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403 @item
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404 If it is @code{nil}, operate on the selected frame.
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405 @item
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406 If it is @code{t}, operate on all frames.
|
|
|
407 @item
|
|
|
408 If it is @code{visible}, operate on all visible frames.
|
|
|
409 @item 0
|
|
|
410 If it is 0, operate on all visible or iconified frames.
|
|
|
411 @item
|
|
|
412 If it is a frame, operate on that frame.
|
|
|
413 @end itemize
|
|
|
414
|
|
|
415 This function always returns @code{nil}.
|
|
|
416 @end deffn
|
|
|
417
|
|
|
418 @node Selecting Windows
|
|
|
419 @section Selecting Windows
|
|
|
420 @cindex selecting windows
|
|
|
421
|
|
|
422 When a window is selected, the buffer in the window becomes the current
|
|
|
423 buffer, and the cursor will appear in it.
|
|
|
424
|
|
|
425 @defun selected-window &optional device
|
|
|
426 This function returns the selected window. This is the window in
|
|
|
427 which the cursor appears and to which many commands apply. Each
|
|
|
428 separate device can have its own selected window, which is remembered
|
|
|
429 as focus changes from device to device. Optional argument @var{device}
|
|
|
430 specifies which device to return the selected window for, and defaults
|
|
|
431 to the selected device.
|
|
|
432 @end defun
|
|
|
433
|
|
|
434 @defun select-window window
|
|
|
435 This function makes @var{window} the selected window. The cursor then
|
|
|
436 appears in @var{window} (on redisplay). The buffer being displayed in
|
|
|
437 @var{window} is immediately designated the current buffer.
|
|
|
438
|
|
|
439 The return value is @var{window}.
|
|
|
440
|
|
|
441 @example
|
|
|
442 @group
|
|
|
443 (setq w (next-window))
|
|
|
444 (select-window w)
|
|
|
445 @result{} #<window 65 on windows.texi>
|
|
|
446 @end group
|
|
|
447 @end example
|
|
|
448 @end defun
|
|
|
449
|
|
|
450 @defmac save-selected-window forms@dots{}
|
|
|
451 This macro records the selected window, executes @var{forms}
|
|
|
452 in sequence, then restores the earlier selected window.
|
|
|
453 It does not save or restore anything about the sizes, arrangement
|
|
|
454 or contents of windows; therefore, if the @var{forms} change them,
|
|
|
455 the changes are permanent.
|
|
|
456 @end defmac
|
|
|
457
|
|
|
458 @cindex finding windows
|
|
|
459 The following functions choose one of the windows on the screen,
|
|
|
460 offering various criteria for the choice.
|
|
|
461
|
|
|
462 @defun get-lru-window &optional frame
|
|
|
463 This function returns the window least recently ``used'' (that is,
|
|
|
464 selected). The selected window is always the most recently used window.
|
|
|
465
|
|
|
466 The selected window can be the least recently used window if it is the
|
|
|
467 only window. A newly created window becomes the least recently used
|
|
|
468 window until it is selected. A minibuffer window is never a candidate.
|
|
|
469
|
|
|
470 The argument @var{frame} controls which windows are considered.
|
|
|
471
|
|
|
472 @itemize @bullet
|
|
|
473 @item
|
|
|
474 If it is @code{nil}, consider windows on the selected frame.
|
|
|
475 @item
|
|
|
476 If it is @code{t}, consider windows on all frames.
|
|
|
477 @item
|
|
|
478 If it is @code{visible}, consider windows on all visible frames.
|
|
|
479 @item
|
|
|
480 If it is 0, consider windows on all visible or iconified frames.
|
|
|
481 @item
|
|
|
482 If it is a frame, consider windows on that frame.
|
|
|
483 @end itemize
|
|
|
484 @end defun
|
|
|
485
|
|
|
486 @defun get-largest-window &optional frame
|
|
|
487 This function returns the window with the largest area (height times
|
|
|
488 width). If there are no side-by-side windows, then this is the window
|
|
|
489 with the most lines. A minibuffer window is never a candidate.
|
|
|
490
|
|
|
491 If there are two windows of the same size, then the function returns
|
|
|
492 the window that is first in the cyclic ordering of windows (see
|
|
|
493 following section), starting from the selected window.
|
|
|
494
|
|
|
495 The argument @var{frame} controls which set of windows are
|
|
|
496 considered. See @code{get-lru-window}, above.
|
|
|
497 @end defun
|
|
|
498
|
|
|
499 @node Cyclic Window Ordering
|
|
|
500 @section Cyclic Ordering of Windows
|
|
|
501 @cindex cyclic ordering of windows
|
|
|
502 @cindex ordering of windows, cyclic
|
|
|
503 @cindex window ordering, cyclic
|
|
|
504
|
|
|
505 When you use the command @kbd{C-x o} (@code{other-window}) to select
|
|
|
506 the next window, it moves through all the windows on the screen in a
|
|
|
507 specific cyclic order. For any given configuration of windows, this
|
|
|
508 order never varies. It is called the @dfn{cyclic ordering of windows}.
|
|
|
509
|
|
|
510 This ordering generally goes from top to bottom, and from left to
|
|
|
511 right. But it may go down first or go right first, depending on the
|
|
|
512 order in which the windows were split.
|
|
|
513
|
|
|
514 If the first split was vertical (into windows one above each other),
|
|
|
515 and then the subwindows were split horizontally, then the ordering is
|
|
|
516 left to right in the top of the frame, and then left to right in the
|
|
|
517 next lower part of the frame, and so on. If the first split was
|
|
|
518 horizontal, the ordering is top to bottom in the left part, and so on.
|
|
|
519 In general, within each set of siblings at any level in the window tree,
|
|
|
520 the order is left to right, or top to bottom.
|
|
|
521
|
|
|
522 @defun next-window &optional window minibuf all-frames
|
|
|
523 @cindex minibuffer window
|
|
|
524 This function returns the window following @var{window} in the cyclic
|
|
|
525 ordering of windows. This is the window that @kbd{C-x o} would select
|
|
|
526 if typed when @var{window} is selected. If @var{window} is the only
|
|
|
527 window visible, then this function returns @var{window}. If omitted,
|
|
|
528 @var{window} defaults to the selected window.
|
|
|
529
|
|
|
530 The value of the argument @var{minibuf} determines whether the
|
|
|
531 minibuffer is included in the window order. Normally, when
|
|
|
532 @var{minibuf} is @code{nil}, the minibuffer is included if it is
|
|
|
533 currently active; this is the behavior of @kbd{C-x o}. (The minibuffer
|
|
|
534 window is active while the minibuffer is in use. @xref{Minibuffers}.)
|
|
|
535
|
|
|
536 If @var{minibuf} is @code{t}, then the cyclic ordering includes the
|
|
|
537 minibuffer window even if it is not active.
|
|
|
538
|
|
|
539 If @var{minibuf} is neither @code{t} nor @code{nil}, then the minibuffer
|
|
|
540 window is not included even if it is active.
|
|
|
541
|
|
|
542 The argument @var{all-frames} specifies which frames to consider. Here
|
|
|
543 are the possible values and their meanings:
|
|
|
544
|
|
|
545 @table @asis
|
|
|
546 @item @code{nil}
|
|
|
547 Consider all the windows in @var{window}'s frame, plus the minibuffer
|
|
|
548 used by that frame even if it lies in some other frame.
|
|
|
549
|
|
|
550 @item @code{t}
|
|
|
551 Consider all windows in all existing frames.
|
|
|
552
|
|
|
553 @item @code{visible}
|
|
|
554 Consider all windows in all visible frames. (To get useful results, you
|
|
|
555 must ensure @var{window} is in a visible frame.)
|
|
|
556
|
|
|
557 @item 0
|
|
|
558 Consider all windows in all visible or iconified frames.
|
|
|
559
|
|
|
560 @item anything else
|
|
|
561 Consider precisely the windows in @var{window}'s frame, and no others.
|
|
|
562 @end table
|
|
|
563
|
|
|
564 This example assumes there are two windows, both displaying the
|
|
|
565 buffer @samp{windows.texi}:
|
|
|
566
|
|
|
567 @example
|
|
|
568 @group
|
|
|
569 (selected-window)
|
|
|
570 @result{} #<window 56 on windows.texi>
|
|
|
571 @end group
|
|
|
572 @group
|
|
|
573 (next-window (selected-window))
|
|
|
574 @result{} #<window 52 on windows.texi>
|
|
|
575 @end group
|
|
|
576 @group
|
|
|
577 (next-window (next-window (selected-window)))
|
|
|
578 @result{} #<window 56 on windows.texi>
|
|
|
579 @end group
|
|
|
580 @end example
|
|
|
581 @end defun
|
|
|
582
|
|
|
583 @defun previous-window &optional window minibuf all-frames
|
|
|
584 This function returns the window preceding @var{window} in the cyclic
|
|
|
585 ordering of windows. The other arguments specify which windows to
|
|
|
586 include in the cycle, as in @code{next-window}.
|
|
|
587 @end defun
|
|
|
588
|
|
|
589 @deffn Command other-window count &optional frame
|
|
|
590 This function selects the @var{count}th following window in the cyclic
|
|
|
591 order. If count is negative, then it selects the @minus{}@var{count}th
|
|
|
592 preceding window. It returns @code{nil}.
|
|
|
593
|
|
|
594 In an interactive call, @var{count} is the numeric prefix argument.
|
|
|
595
|
|
|
596 The argument @var{frame} controls which set of windows are considered.
|
|
|
597 @itemize @bullet
|
|
|
598 @item
|
|
|
599 If it is @code{nil} or omitted, then windows on the selected frame are
|
|
|
600 considered.
|
|
|
601 @item
|
|
|
602 If it is a frame, then windows on that frame are considered.
|
|
|
603 @item
|
|
|
604 If it is @code{t}, then windows on all frames that currently exist
|
|
|
605 (including invisible and iconified frames) are considered.
|
|
|
606 @item
|
|
|
607 If it is the symbol @code{visible}, then windows on all visible frames
|
|
|
608 are considered.
|
|
|
609 @item
|
|
|
610 If it is the number 0, then windows on all visible and iconified frames
|
|
|
611 are considered.
|
|
|
612 @item
|
|
|
613 If it is any other value, then the behavior is undefined.
|
|
|
614 @end itemize
|
|
|
615 @end deffn
|
|
|
616
|
|
|
617 @c Emacs 19 feature
|
|
|
618 @defun walk-windows proc &optional minibuf all-frames
|
|
|
619 This function cycles through all windows, calling @code{proc}
|
|
|
620 once for each window with the window as its sole argument.
|
|
|
621
|
|
|
622 The optional arguments @var{minibuf} and @var{all-frames} specify the
|
|
|
623 set of windows to include in the scan. See @code{next-window}, above,
|
|
|
624 for details.
|
|
|
625 @end defun
|
|
|
626
|
|
|
627 @node Buffers and Windows
|
|
|
628 @section Buffers and Windows
|
|
|
629 @cindex examining windows
|
|
|
630 @cindex windows, controlling precisely
|
|
|
631 @cindex buffers, controlled in windows
|
|
|
632
|
|
|
633 This section describes low-level functions to examine windows or to
|
|
|
634 display buffers in windows in a precisely controlled fashion.
|
|
|
635 @iftex
|
|
|
636 See the following section for
|
|
|
637 @end iftex
|
|
|
638 @ifinfo
|
|
|
639 @xref{Displaying Buffers}, for
|
|
|
640 @end ifinfo
|
|
|
641 related functions that find a window to use and specify a buffer for it.
|
|
|
642 The functions described there are easier to use than these, but they
|
|
|
643 employ heuristics in choosing or creating a window; use these functions
|
|
|
644 when you need complete control.
|
|
|
645
|
|
|
646 @defun set-window-buffer window buffer-or-name
|
|
|
647 This function makes @var{window} display @var{buffer-or-name} as its
|
|
|
648 contents. It returns @code{nil}.
|
|
|
649
|
|
|
650 @example
|
|
|
651 @group
|
|
|
652 (set-window-buffer (selected-window) "foo")
|
|
|
653 @result{} nil
|
|
|
654 @end group
|
|
|
655 @end example
|
|
|
656 @end defun
|
|
|
657
|
|
|
658 @defun window-buffer &optional window
|
|
|
659 This function returns the buffer that @var{window} is displaying. If
|
|
|
660 @var{window} is omitted, this function returns the buffer for the
|
|
|
661 selected window.
|
|
|
662
|
|
|
663 @example
|
|
|
664 @group
|
|
|
665 (window-buffer)
|
|
|
666 @result{} #<buffer windows.texi>
|
|
|
667 @end group
|
|
|
668 @end example
|
|
|
669 @end defun
|
|
|
670
|
|
|
671 @defun get-buffer-window buffer-or-name &optional frame
|
|
|
672 This function returns a window currently displaying
|
|
|
673 @var{buffer-or-name}, or @code{nil} if there is none. If there are
|
|
|
674 several such windows, then the function returns the first one in the
|
|
|
675 cyclic ordering of windows, starting from the selected window.
|
|
|
676 @xref{Cyclic Window Ordering}.
|
|
|
677
|
|
|
678 The argument @var{all-frames} controls which windows to consider.
|
|
|
679
|
|
|
680 @itemize @bullet
|
|
|
681 @item
|
|
|
682 If it is @code{nil}, consider windows on the selected frame.
|
|
|
683 @item
|
|
|
684 If it is @code{t}, consider windows on all frames.
|
|
|
685 @item
|
|
|
686 If it is @code{visible}, consider windows on all visible frames.
|
|
|
687 @item
|
|
|
688 If it is 0, consider windows on all visible or iconified frames.
|
|
|
689 @item
|
|
|
690 If it is a frame, consider windows on that frame.
|
|
|
691 @end itemize
|
|
|
692 @end defun
|
|
|
693
|
|
|
694 @node Displaying Buffers
|
|
|
695 @section Displaying Buffers in Windows
|
|
|
696 @cindex switching to a buffer
|
|
|
697 @cindex displaying a buffer
|
|
|
698
|
|
|
699 In this section we describe convenient functions that choose a window
|
|
|
700 automatically and use it to display a specified buffer. These functions
|
|
|
701 can also split an existing window in certain circumstances. We also
|
|
|
702 describe variables that parameterize the heuristics used for choosing a
|
|
|
703 window.
|
|
|
704 @iftex
|
|
|
705 See the preceding section for
|
|
|
706 @end iftex
|
|
|
707 @ifinfo
|
|
|
708 @xref{Buffers and Windows}, for
|
|
|
709 @end ifinfo
|
|
|
710 low-level functions that give you more precise control.
|
|
|
711
|
|
|
712 Do not use the functions in this section in order to make a buffer
|
|
|
713 current so that a Lisp program can access or modify it; they are too
|
|
|
714 drastic for that purpose, since they change the display of buffers in
|
|
|
715 windows, which is gratuitous and will surprise the user. Instead, use
|
|
|
716 @code{set-buffer} (@pxref{Current Buffer}) and @code{save-excursion}
|
|
|
717 (@pxref{Excursions}), which designate buffers as current for programmed
|
|
|
718 access without affecting the display of buffers in windows.
|
|
|
719
|
|
|
720 @deffn Command switch-to-buffer buffer-or-name &optional norecord
|
|
|
721 This function makes @var{buffer-or-name} the current buffer, and also
|
|
|
722 displays the buffer in the selected window. This means that a human can
|
|
|
723 see the buffer and subsequent keyboard commands will apply to it.
|
|
|
724 Contrast this with @code{set-buffer}, which makes @var{buffer-or-name}
|
|
|
725 the current buffer but does not display it in the selected window.
|
|
|
726 @xref{Current Buffer}.
|
|
|
727
|
|
|
728 If @var{buffer-or-name} does not identify an existing buffer, then a new
|
|
|
729 buffer by that name is created. The major mode for the new buffer is
|
|
|
730 set according to the variable @code{default-major-mode}. @xref{Auto
|
|
|
731 Major Mode}.
|
|
|
732
|
|
|
733 Normally the specified buffer is put at the front of the buffer list.
|
|
|
734 This affects the operation of @code{other-buffer}. However, if
|
|
|
735 @var{norecord} is non-@code{nil}, this is not done. @xref{The Buffer
|
|
|
736 List}.
|
|
|
737
|
|
|
738 The @code{switch-to-buffer} function is often used interactively, as
|
|
|
739 the binding of @kbd{C-x b}. It is also used frequently in programs. It
|
|
|
740 always returns @code{nil}.
|
|
|
741 @end deffn
|
|
|
742
|
|
|
743 @deffn Command switch-to-buffer-other-window buffer-or-name
|
|
|
744 This function makes @var{buffer-or-name} the current buffer and
|
|
|
745 displays it in a window not currently selected. It then selects that
|
|
|
746 window. The handling of the buffer is the same as in
|
|
|
747 @code{switch-to-buffer}.
|
|
|
748
|
|
|
749 The currently selected window is absolutely never used to do the job.
|
|
|
750 If it is the only window, then it is split to make a distinct window for
|
|
|
751 this purpose. If the selected window is already displaying the buffer,
|
|
|
752 then it continues to do so, but another window is nonetheless found to
|
|
|
753 display it in as well.
|
|
|
754 @end deffn
|
|
|
755
|
|
|
756 @defun pop-to-buffer buffer-or-name &optional other-window on-frame
|
|
|
757 This function makes @var{buffer-or-name} the current buffer and
|
|
|
758 switches to it in some window, preferably not the window previously
|
|
|
759 selected. The ``popped-to'' window becomes the selected window within
|
|
|
760 its frame.
|
|
|
761
|
|
|
762 If the variable @code{pop-up-frames} is non-@code{nil},
|
|
|
763 @code{pop-to-buffer} looks for a window in any visible frame already
|
|
|
764 displaying the buffer; if there is one, it returns that window and makes
|
|
|
765 it be selected within its frame. If there is none, it creates a new
|
|
|
766 frame and displays the buffer in it.
|
|
|
767
|
|
|
768 If @code{pop-up-frames} is @code{nil}, then @code{pop-to-buffer}
|
|
|
769 operates entirely within the selected frame. (If the selected frame has
|
|
|
770 just a minibuffer, @code{pop-to-buffer} operates within the most
|
|
|
771 recently selected frame that was not just a minibuffer.)
|
|
|
772
|
|
|
773 If the variable @code{pop-up-windows} is non-@code{nil}, windows may
|
|
|
774 be split to create a new window that is different from the original
|
|
|
775 window. For details, see @ref{Choosing Window}.
|
|
|
776
|
|
|
777 If @var{other-window} is non-@code{nil}, @code{pop-to-buffer} finds or
|
|
|
778 creates another window even if @var{buffer-or-name} is already visible
|
|
|
779 in the selected window. Thus @var{buffer-or-name} could end up
|
|
|
780 displayed in two windows. On the other hand, if @var{buffer-or-name} is
|
|
|
781 already displayed in the selected window and @var{other-window} is
|
|
|
782 @code{nil}, then the selected window is considered sufficient display
|
|
|
783 for @var{buffer-or-name}, so that nothing needs to be done.
|
|
|
784
|
|
|
785 All the variables that affect @code{display-buffer} affect
|
|
|
786 @code{pop-to-buffer} as well. @xref{Choosing Window}.
|
|
|
787
|
|
|
788 If @var{buffer-or-name} is a string that does not name an existing
|
|
|
789 buffer, a buffer by that name is created. The major mode for the new
|
|
|
790 buffer is set according to the variable @code{default-major-mode}.
|
|
|
791 @xref{Auto Major Mode}.
|
|
|
792
|
|
|
793 If @var{on-frame} is non-@code{nil}, it is the frame to pop to this
|
|
|
794 buffer on.
|
|
|
795
|
|
|
796 An example use of this function is found at the end of @ref{Filter
|
|
|
797 Functions}.
|
|
|
798 @end defun
|
|
|
799
|
|
|
800 @deffn Command replace-buffer-in-windows buffer
|
|
|
801 This function replaces @var{buffer} with some other buffer in all
|
|
|
802 windows displaying it. The other buffer used is chosen with
|
|
|
803 @code{other-buffer}. In the usual applications of this function, you
|
|
|
804 don't care which other buffer is used; you just want to make sure that
|
|
|
805 @var{buffer} is no longer displayed.
|
|
|
806
|
|
|
807 This function returns @code{nil}.
|
|
|
808 @end deffn
|
|
|
809
|
|
|
810 @node Choosing Window
|
|
|
811 @section Choosing a Window for Display
|
|
|
812
|
|
|
813 This section describes the basic facility that chooses a window to
|
|
|
814 display a buffer in---@code{display-buffer}. All the higher-level
|
|
|
815 functions and commands use this subroutine. Here we describe how to use
|
|
|
816 @code{display-buffer} and how to customize it.
|
|
|
817
|
|
|
818 @deffn Command display-buffer buffer-or-name &optional not-this-window
|
|
|
819 This command makes @var{buffer-or-name} appear in some window, like
|
|
|
820 @code{pop-to-buffer}, but it does not select that window and does not
|
|
|
821 make the buffer current. The identity of the selected window is
|
|
|
822 unaltered by this function.
|
|
|
823
|
|
|
824 If @var{not-this-window} is non-@code{nil}, it means to display the
|
|
|
825 specified buffer in a window other than the selected one, even if it is
|
|
|
826 already on display in the selected window. This can cause the buffer to
|
|
|
827 appear in two windows at once. Otherwise, if @var{buffer-or-name} is
|
|
|
828 already being displayed in any window, that is good enough, so this
|
|
|
829 function does nothing.
|
|
|
830
|
|
|
831 @code{display-buffer} returns the window chosen to display
|
|
|
832 @var{buffer-or-name}.
|
|
|
833
|
|
|
834 Precisely how @code{display-buffer} finds or creates a window depends on
|
|
|
835 the variables described below.
|
|
|
836 @end deffn
|
|
|
837
|
|
|
838 @c Emacs 19 feature
|
|
|
839 @cindex dedicated window
|
|
|
840 A window can be marked as ``dedicated'' to a particular buffer.
|
|
|
841 Then XEmacs will not automatically change which buffer appears in the
|
|
|
842 window, such as @code{display-buffer} might normally do.
|
|
|
843
|
|
|
844 @defun window-dedicated-p window
|
|
|
845 This function returns @var{window}'s dedicated object, usually @code{t}
|
|
|
846 or @code{nil}.
|
|
|
847 @end defun
|
|
|
848
|
|
|
849 @defun set-window-buffer-dedicated window buffer
|
|
|
850 This function makes @var{window} display @var{buffer} and be dedicated
|
|
|
851 to that buffer. Then XEmacs will not automatically change which buffer
|
|
|
852 appears in @var{window}. If @var{buffer} is @code{nil}, this function makes
|
|
|
853 @var{window} not be dedicated (but doesn't change which buffer appears
|
|
|
854 in it currently).
|
|
|
855 @end defun
|
|
|
856
|
|
|
857 @defopt pop-up-windows
|
|
|
858 This variable controls whether @code{display-buffer} makes new windows.
|
|
|
859 If it is non-@code{nil} and there is only one window, then that window
|
|
|
860 is split. If it is @code{nil}, then @code{display-buffer} does not
|
|
|
861 split the single window, but uses it whole.
|
|
|
862 @end defopt
|
|
|
863
|
|
|
864 @defopt split-height-threshold
|
|
|
865 This variable determines when @code{display-buffer} may split a window,
|
|
|
866 if there are multiple windows. @code{display-buffer} always splits the
|
|
|
867 largest window if it has at least this many lines. If the largest
|
|
|
868 window is not this tall, it is split only if it is the sole window and
|
|
|
869 @code{pop-up-windows} is non-@code{nil}.
|
|
|
870 @end defopt
|
|
|
871
|
|
|
872 @c Emacs 19 feature
|
|
|
873 @defopt pop-up-frames
|
|
|
874 This variable controls whether @code{display-buffer} makes new frames.
|
|
|
875 If it is non-@code{nil}, @code{display-buffer} looks for an existing
|
|
|
876 window already displaying the desired buffer, on any visible frame. If
|
|
|
877 it finds one, it returns that window. Otherwise it makes a new frame.
|
|
|
878 The variables @code{pop-up-windows} and @code{split-height-threshold} do
|
|
|
879 not matter if @code{pop-up-frames} is non-@code{nil}.
|
|
|
880
|
|
|
881 If @code{pop-up-frames} is @code{nil}, then @code{display-buffer} either
|
|
|
882 splits a window or reuses one.
|
|
|
883
|
|
|
884 @xref{Frames}, for more information.
|
|
|
885 @end defopt
|
|
|
886
|
|
|
887 @c Emacs 19 feature
|
|
|
888 @defvar pop-up-frame-function
|
|
|
889 This variable specifies how to make a new frame if @code{pop-up-frames}
|
|
|
890 is non-@code{nil}.
|
|
|
891
|
|
|
892 Its value should be a function of no arguments. When
|
|
|
893 @code{display-buffer} makes a new frame, it does so by calling that
|
|
|
894 function, which should return a frame. The default value of the
|
|
54
|
895 variable is a function that creates a frame using properties from
|
|
|
896 @code{pop-up-frame-plist}.
|
|
0
|
897 @end defvar
|
|
|
898
|
|
54
|
899 @defvar pop-up-frame-plist
|
|
|
900 This variable holds a plist specifying frame properties used when
|
|
|
901 @code{display-buffer} makes a new frame. @xref{Frame Properties}, for
|
|
|
902 more information about frame properties.
|
|
0
|
903 @end defvar
|
|
|
904
|
|
|
905 @defvar special-display-buffer-names
|
|
|
906 A list of buffer names for buffers that should be displayed specially.
|
|
|
907 If the buffer's name is in this list, @code{display-buffer} handles the
|
|
|
908 buffer specially.
|
|
|
909
|
|
|
910 By default, special display means to give the buffer a dedicated frame.
|
|
|
911
|
|
|
912 If an element is a list, instead of a string, then the @sc{car} of the
|
|
|
913 list is the buffer name, and the rest of the list says how to create the
|
|
|
914 frame. There are two possibilities for the rest of the list. It can be
|
|
54
|
915 a plist, specifying frame properties, or it can contain a function and
|
|
0
|
916 arguments to give to it. (The function's first argument is always the
|
|
|
917 buffer to be displayed; the arguments from the list come after that.)
|
|
|
918 @end defvar
|
|
|
919
|
|
|
920 @defvar special-display-regexps
|
|
|
921 A list of regular expressions that specify buffers that should be
|
|
|
922 displayed specially. If the buffer's name matches any of the regular
|
|
|
923 expressions in this list, @code{display-buffer} handles the buffer
|
|
|
924 specially.
|
|
|
925
|
|
|
926 By default, special display means to give the buffer a dedicated frame.
|
|
|
927
|
|
|
928 If an element is a list, instead of a string, then the @sc{car} of the
|
|
|
929 list is the regular expression, and the rest of the list says how to
|
|
|
930 create the frame. See above, under @code{special-display-buffer-names}.
|
|
|
931 @end defvar
|
|
|
932
|
|
|
933 @defvar special-display-function
|
|
|
934 This variable holds the function to call to display a buffer specially.
|
|
|
935 It receives the buffer as an argument, and should return the window in
|
|
|
936 which it is displayed.
|
|
|
937
|
|
|
938 The default value of this variable is
|
|
|
939 @code{special-display-popup-frame}.
|
|
|
940 @end defvar
|
|
|
941
|
|
|
942 @defun special-display-popup-frame buffer
|
|
|
943 This function makes @var{buffer} visible in a frame of its own. If
|
|
|
944 @var{buffer} is already displayed in a window in some frame, it makes
|
|
|
945 the frame visible and raises it, to use that window. Otherwise, it
|
|
|
946 creates a frame that will be dedicated to @var{buffer}.
|
|
|
947
|
|
|
948 This function uses an existing window displaying @var{buffer} whether or
|
|
|
949 not it is in a frame of its own; but if you set up the above variables
|
|
|
950 in your init file, before @var{buffer} was created, then presumably the
|
|
|
951 window was previously made by this function.
|
|
|
952 @end defun
|
|
|
953
|
|
54
|
954 @defopt special-display-frame-plist
|
|
|
955 This variable holds frame properties for
|
|
0
|
956 @code{special-display-popup-frame} to use when it creates a frame.
|
|
|
957 @end defopt
|
|
|
958
|
|
|
959 @defvar same-window-buffer-names
|
|
|
960 A list of buffer names for buffers that should be displayed in the
|
|
|
961 selected window. If the buffer's name is in this list,
|
|
|
962 @code{display-buffer} handles the buffer by switching to it in the
|
|
|
963 selected window.
|
|
|
964 @end defvar
|
|
|
965
|
|
|
966 @defvar same-window-regexps
|
|
|
967 A list of regular expressions that specify buffers that should be
|
|
|
968 displayed in the selected window. If the buffer's name matches any of
|
|
|
969 the regular expressions in this list, @code{display-buffer} handles the
|
|
|
970 buffer by switching to it in the selected window.
|
|
|
971 @end defvar
|
|
|
972
|
|
|
973 @c Emacs 19 feature
|
|
|
974 @defvar display-buffer-function
|
|
|
975 This variable is the most flexible way to customize the behavior of
|
|
|
976 @code{display-buffer}. If it is non-@code{nil}, it should be a function
|
|
|
977 that @code{display-buffer} calls to do the work. The function should
|
|
|
978 accept two arguments, the same two arguments that @code{display-buffer}
|
|
|
979 received. It should choose or create a window, display the specified
|
|
|
980 buffer, and then return the window.
|
|
|
981
|
|
|
982 This hook takes precedence over all the other options and hooks
|
|
|
983 described above.
|
|
|
984 @end defvar
|
|
|
985
|
|
|
986 @c Emacs 19 feature
|
|
|
987 @cindex dedicated window
|
|
|
988 A window can be marked as ``dedicated'' to its buffer. Then
|
|
|
989 @code{display-buffer} does not try to use that window.
|
|
|
990
|
|
|
991 @defun window-dedicated-p window
|
|
|
992 This function returns @code{t} if @var{window} is marked as dedicated;
|
|
|
993 otherwise @code{nil}.
|
|
|
994 @end defun
|
|
|
995
|
|
|
996 @defun set-window-dedicated-p window flag
|
|
|
997 This function marks @var{window} as dedicated if @var{flag} is
|
|
|
998 non-@code{nil}, and nondedicated otherwise.
|
|
|
999 @end defun
|
|
|
1000
|
|
|
1001 @node Window Point
|
|
|
1002 @section Windows and Point
|
|
|
1003 @cindex window position
|
|
|
1004 @cindex window point
|
|
|
1005 @cindex position in window
|
|
|
1006 @cindex point in window
|
|
|
1007
|
|
|
1008 Each window has its own value of point, independent of the value of
|
|
|
1009 point in other windows displaying the same buffer. This makes it useful
|
|
|
1010 to have multiple windows showing one buffer.
|
|
|
1011
|
|
|
1012 @itemize @bullet
|
|
|
1013 @item
|
|
|
1014 The window point is established when a window is first created; it is
|
|
|
1015 initialized from the buffer's point, or from the window point of another
|
|
|
1016 window opened on the buffer if such a window exists.
|
|
|
1017
|
|
|
1018 @item
|
|
|
1019 Selecting a window sets the value of point in its buffer to the window's
|
|
|
1020 value of point. Conversely, deselecting a window sets the window's
|
|
|
1021 value of point from that of the buffer. Thus, when you switch between
|
|
|
1022 windows that display a given buffer, the point value for the selected
|
|
|
1023 window is in effect in the buffer, while the point values for the other
|
|
|
1024 windows are stored in those windows.
|
|
|
1025
|
|
|
1026 @item
|
|
|
1027 As long as the selected window displays the current buffer, the window's
|
|
|
1028 point and the buffer's point always move together; they remain equal.
|
|
|
1029
|
|
|
1030 @item
|
|
|
1031 @xref{Positions}, for more details on buffer positions.
|
|
|
1032 @end itemize
|
|
|
1033
|
|
|
1034 As far as the user is concerned, point is where the cursor is, and
|
|
|
1035 when the user switches to another buffer, the cursor jumps to the
|
|
|
1036 position of point in that buffer.
|
|
|
1037
|
|
|
1038 @defun window-point window
|
|
|
1039 This function returns the current position of point in @var{window}.
|
|
|
1040 For a nonselected window, this is the value point would have (in that
|
|
|
1041 window's buffer) if that window were selected.
|
|
|
1042
|
|
|
1043 When @var{window} is the selected window and its buffer is also the
|
|
|
1044 current buffer, the value returned is the same as point in that buffer.
|
|
|
1045
|
|
|
1046 Strictly speaking, it would be more correct to return the
|
|
|
1047 ``top-level'' value of point, outside of any @code{save-excursion}
|
|
|
1048 forms. But that value is hard to find.
|
|
|
1049 @end defun
|
|
|
1050
|
|
|
1051 @defun set-window-point window position
|
|
|
1052 This function positions point in @var{window} at position
|
|
|
1053 @var{position} in @var{window}'s buffer.
|
|
|
1054 @end defun
|
|
|
1055
|
|
|
1056 @node Window Start
|
|
|
1057 @section The Window Start Position
|
|
|
1058
|
|
|
1059 Each window contains a marker used to keep track of a buffer position
|
|
|
1060 that specifies where in the buffer display should start. This position
|
|
|
1061 is called the @dfn{display-start} position of the window (or just the
|
|
|
1062 @dfn{start}). The character after this position is the one that appears
|
|
|
1063 at the upper left corner of the window. It is usually, but not
|
|
|
1064 inevitably, at the beginning of a text line.
|
|
|
1065
|
|
|
1066 @defun window-start &optional window
|
|
|
1067 @cindex window top line
|
|
|
1068 This function returns the display-start position of window
|
|
|
1069 @var{window}. If @var{window} is @code{nil}, the selected window is
|
|
|
1070 used. For example,
|
|
|
1071
|
|
|
1072 @example
|
|
|
1073 @group
|
|
|
1074 (window-start)
|
|
|
1075 @result{} 7058
|
|
|
1076 @end group
|
|
|
1077 @end example
|
|
|
1078
|
|
|
1079 When you create a window, or display a different buffer in it, the
|
|
|
1080 display-start position is set to a display-start position recently used
|
|
|
1081 for the same buffer, or 1 if the buffer doesn't have any.
|
|
|
1082
|
|
|
1083 For a realistic example, see the description of @code{count-lines} in
|
|
|
1084 @ref{Text Lines}.
|
|
|
1085 @end defun
|
|
|
1086
|
|
|
1087 @defun window-end &optional window
|
|
|
1088 This function returns the position of the end of the display in window
|
|
|
1089 @var{window}. If @var{window} is @code{nil}, the selected window is
|
|
|
1090 used.
|
|
|
1091
|
|
|
1092 Simply changing the buffer text or moving point does not update the
|
|
|
1093 value that @code{window-end} returns. The value is updated only when
|
|
|
1094 Emacs redisplays and redisplay actually finishes.
|
|
|
1095
|
|
|
1096 If the last redisplay of @var{window} was preempted, and did not finish,
|
|
|
1097 Emacs does not know the position of the end of display in that window.
|
|
|
1098 In that case, this function returns a value that is not correct. In a
|
|
|
1099 future version, @code{window-end} will return @code{nil} in that case.
|
|
|
1100 @ignore
|
|
|
1101 in that case, this function returns @code{nil}. You can compute where
|
|
|
1102 the end of the window @emph{would} have been, if redisplay had finished,
|
|
|
1103 like this:
|
|
|
1104
|
|
|
1105 @example
|
|
|
1106 (save-excursion
|
|
|
1107 (goto-char (window-start window))
|
|
|
1108 (vertical-motion (1- (window-height window))
|
|
|
1109 window)
|
|
|
1110 (point))
|
|
|
1111 @end example
|
|
|
1112 @end ignore
|
|
|
1113 @end defun
|
|
|
1114
|
|
|
1115 @defun set-window-start window position &optional noforce
|
|
|
1116 This function sets the display-start position of @var{window} to
|
|
|
1117 @var{position} in @var{window}'s buffer. It returns @var{position}.
|
|
|
1118
|
|
|
1119 The display routines insist that the position of point be visible when a
|
|
|
1120 buffer is displayed. Normally, they change the display-start position
|
|
|
1121 (that is, scroll the window) whenever necessary to make point visible.
|
|
|
1122 However, if you specify the start position with this function using
|
|
|
1123 @code{nil} for @var{noforce}, it means you want display to start at
|
|
|
1124 @var{position} even if that would put the location of point off the
|
|
|
1125 screen. If this does place point off screen, the display routines move
|
|
|
1126 point to the left margin on the middle line in the window.
|
|
|
1127
|
|
|
1128 For example, if point @w{is 1} and you set the start of the window @w{to
|
|
|
1129 2}, then point would be ``above'' the top of the window. The display
|
|
|
1130 routines will automatically move point if it is still 1 when redisplay
|
|
|
1131 occurs. Here is an example:
|
|
|
1132
|
|
|
1133 @example
|
|
|
1134 @group
|
|
|
1135 ;; @r{Here is what @samp{foo} looks like before executing}
|
|
|
1136 ;; @r{the @code{set-window-start} expression.}
|
|
|
1137 @end group
|
|
|
1138
|
|
|
1139 @group
|
|
|
1140 ---------- Buffer: foo ----------
|
|
|
1141 @point{}This is the contents of buffer foo.
|
|
|
1142 2
|
|
|
1143 3
|
|
|
1144 4
|
|
|
1145 5
|
|
|
1146 6
|
|
|
1147 ---------- Buffer: foo ----------
|
|
|
1148 @end group
|
|
|
1149
|
|
|
1150 @group
|
|
|
1151 (set-window-start
|
|
|
1152 (selected-window)
|
|
|
1153 (1+ (window-start)))
|
|
|
1154 @result{} 2
|
|
|
1155 @end group
|
|
|
1156
|
|
|
1157 @group
|
|
|
1158 ;; @r{Here is what @samp{foo} looks like after executing}
|
|
|
1159 ;; @r{the @code{set-window-start} expression.}
|
|
|
1160 ---------- Buffer: foo ----------
|
|
|
1161 his is the contents of buffer foo.
|
|
|
1162 2
|
|
|
1163 3
|
|
|
1164 @point{}4
|
|
|
1165 5
|
|
|
1166 6
|
|
|
1167 ---------- Buffer: foo ----------
|
|
|
1168 @end group
|
|
|
1169 @end example
|
|
|
1170
|
|
|
1171 If @var{noforce} is non-@code{nil}, and @var{position} would place point
|
|
|
1172 off screen at the next redisplay, then redisplay computes a new window-start
|
|
|
1173 position that works well with point, and thus @var{position} is not used.
|
|
|
1174 @end defun
|
|
|
1175
|
|
|
1176 @defun pos-visible-in-window-p &optional position window
|
|
|
1177 This function returns @code{t} if @var{position} is within the range
|
|
|
1178 of text currently visible on the screen in @var{window}. It returns
|
|
|
1179 @code{nil} if @var{position} is scrolled vertically out of view. The
|
|
|
1180 argument @var{position} defaults to the current position of point;
|
|
|
1181 @var{window}, to the selected window. Here is an example:
|
|
|
1182
|
|
|
1183 @example
|
|
|
1184 @group
|
|
|
1185 (or (pos-visible-in-window-p
|
|
|
1186 (point) (selected-window))
|
|
|
1187 (recenter 0))
|
|
|
1188 @end group
|
|
|
1189 @end example
|
|
|
1190
|
|
|
1191 The @code{pos-visible-in-window-p} function considers only vertical
|
|
|
1192 scrolling. If @var{position} is out of view only because @var{window}
|
|
|
1193 has been scrolled horizontally, @code{pos-visible-in-window-p} returns
|
|
|
1194 @code{t}. @xref{Horizontal Scrolling}.
|
|
|
1195 @end defun
|
|
|
1196
|
|
|
1197 @node Vertical Scrolling
|
|
|
1198 @section Vertical Scrolling
|
|
|
1199 @cindex vertical scrolling
|
|
|
1200 @cindex scrolling vertically
|
|
|
1201
|
|
|
1202 Vertical scrolling means moving the text up or down in a window. It
|
|
|
1203 works by changing the value of the window's display-start location. It
|
|
|
1204 may also change the value of @code{window-point} to keep it on the
|
|
|
1205 screen.
|
|
|
1206
|
|
|
1207 In the commands @code{scroll-up} and @code{scroll-down}, the directions
|
|
|
1208 ``up'' and ``down'' refer to the motion of the text in the buffer at which
|
|
|
1209 you are looking through the window. Imagine that the text is
|
|
|
1210 written on a long roll of paper and that the scrolling commands move the
|
|
|
1211 paper up and down. Thus, if you are looking at text in the middle of a
|
|
|
1212 buffer and repeatedly call @code{scroll-down}, you will eventually see
|
|
|
1213 the beginning of the buffer.
|
|
|
1214
|
|
|
1215 Some people have urged that the opposite convention be used: they
|
|
|
1216 imagine that the window moves over text that remains in place. Then
|
|
|
1217 ``down'' commands would take you to the end of the buffer. This view is
|
|
|
1218 more consistent with the actual relationship between windows and the
|
|
|
1219 text in the buffer, but it is less like what the user sees. The
|
|
|
1220 position of a window on the terminal does not move, and short scrolling
|
|
|
1221 commands clearly move the text up or down on the screen. We have chosen
|
|
|
1222 names that fit the user's point of view.
|
|
|
1223
|
|
|
1224 The scrolling functions (aside from @code{scroll-other-window}) have
|
|
|
1225 unpredictable results if the current buffer is different from the buffer
|
|
|
1226 that is displayed in the selected window. @xref{Current Buffer}.
|
|
|
1227
|
|
|
1228 @deffn Command scroll-up &optional count
|
|
|
1229 This function scrolls the text in the selected window upward
|
|
|
1230 @var{count} lines. If @var{count} is negative, scrolling is actually
|
|
|
1231 downward.
|
|
|
1232
|
|
|
1233 If @var{count} is @code{nil} (or omitted), then the length of scroll
|
|
|
1234 is @code{next-screen-context-lines} lines less than the usable height of
|
|
|
1235 the window (not counting its modeline).
|
|
|
1236
|
|
|
1237 @code{scroll-up} returns @code{nil}.
|
|
|
1238 @end deffn
|
|
|
1239
|
|
|
1240 @deffn Command scroll-down &optional count
|
|
|
1241 This function scrolls the text in the selected window downward
|
|
|
1242 @var{count} lines. If @var{count} is negative, scrolling is actually
|
|
|
1243 upward.
|
|
|
1244
|
|
|
1245 If @var{count} is omitted or @code{nil}, then the length of the scroll
|
|
|
1246 is @code{next-screen-context-lines} lines less than the usable height of
|
|
|
1247 the window (not counting its mode line).
|
|
|
1248
|
|
|
1249 @code{scroll-down} returns @code{nil}.
|
|
|
1250 @end deffn
|
|
|
1251
|
|
|
1252 @deffn Command scroll-other-window &optional count
|
|
|
1253 This function scrolls the text in another window upward @var{count}
|
|
|
1254 lines. Negative values of @var{count}, or @code{nil}, are handled
|
|
|
1255 as in @code{scroll-up}.
|
|
|
1256
|
|
|
1257 You can specify a buffer to scroll with the variable
|
|
|
1258 @code{other-window-scroll-buffer}. When the selected window is the
|
|
|
1259 minibuffer, the next window is normally the one at the top left corner.
|
|
|
1260 You can specify a different window to scroll with the variable
|
|
|
1261 @code{minibuffer-scroll-window}. This variable has no effect when any
|
|
|
1262 other window is selected. @xref{Minibuffer Misc}.
|
|
|
1263
|
|
|
1264 When the minibuffer is active, it is the next window if the selected
|
|
|
1265 window is the one at the bottom right corner. In this case,
|
|
|
1266 @code{scroll-other-window} attempts to scroll the minibuffer. If the
|
|
|
1267 minibuffer contains just one line, it has nowhere to scroll to, so the
|
|
|
1268 line reappears after the echo area momentarily displays the message
|
|
|
1269 ``Beginning of buffer''.
|
|
|
1270 @end deffn
|
|
|
1271
|
|
|
1272 @c Emacs 19 feature
|
|
|
1273 @defvar other-window-scroll-buffer
|
|
|
1274 If this variable is non-@code{nil}, it tells @code{scroll-other-window}
|
|
|
1275 which buffer to scroll.
|
|
|
1276 @end defvar
|
|
|
1277
|
|
|
1278 @defopt scroll-step
|
|
|
1279 This variable controls how scrolling is done automatically when point
|
|
|
1280 moves off the screen. If the value is zero, then redisplay scrolls the
|
|
|
1281 text to center point vertically in the window. If the value is a
|
|
|
1282 positive integer @var{n}, then redisplay brings point back on screen by
|
|
|
1283 scrolling @var{n} lines in either direction, if possible; otherwise, it
|
|
|
1284 centers point. The default value is zero.
|
|
|
1285 @end defopt
|
|
|
1286
|
|
213
|
1287 @defopt scroll-conservatively
|
|
|
1288 This variable controls how many lines Emacs tries to scroll before
|
|
|
1289 recentering. If you set it to a small number, then when you move point
|
|
|
1290 a short distance off the screen, XEmacs will scroll the screen just far
|
|
|
1291 enough to bring point back on screen, provided that does not exceed
|
|
280
|
1292 @code{scroll-conservatively} lines. This variable overrides the
|
|
|
1293 redisplay preemption.
|
|
213
|
1294 @end defopt
|
|
|
1295
|
|
0
|
1296 @defopt next-screen-context-lines
|
|
|
1297 The value of this variable is the number of lines of continuity to
|
|
|
1298 retain when scrolling by full screens. For example, @code{scroll-up}
|
|
|
1299 with an argument of @code{nil} scrolls so that this many lines at the
|
|
|
1300 bottom of the window appear instead at the top. The default value is
|
|
|
1301 @code{2}.
|
|
|
1302 @end defopt
|
|
|
1303
|
|
|
1304 @deffn Command recenter &optional count
|
|
|
1305 @cindex centering point
|
|
|
1306 This function scrolls the selected window to put the text where point
|
|
|
1307 is located at a specified vertical position within the window.
|
|
|
1308
|
|
|
1309 If @var{count} is a nonnegative number, it puts the line containing
|
|
|
1310 point @var{count} lines down from the top of the window. If @var{count}
|
|
|
1311 is a negative number, then it counts upward from the bottom of the
|
|
|
1312 window, so that @minus{}1 stands for the last usable line in the window.
|
|
|
1313 If @var{count} is a non-@code{nil} list, then it stands for the line in
|
|
|
1314 the middle of the window.
|
|
|
1315
|
|
|
1316 If @var{count} is @code{nil}, @code{recenter} puts the line containing
|
|
|
1317 point in the middle of the window, then clears and redisplays the entire
|
|
|
1318 selected frame.
|
|
|
1319
|
|
|
1320 When @code{recenter} is called interactively, @var{count} is the raw
|
|
|
1321 prefix argument. Thus, typing @kbd{C-u} as the prefix sets the
|
|
|
1322 @var{count} to a non-@code{nil} list, while typing @kbd{C-u 4} sets
|
|
|
1323 @var{count} to 4, which positions the current line four lines from the
|
|
|
1324 top.
|
|
|
1325
|
|
|
1326 With an argument of zero, @code{recenter} positions the current line at
|
|
|
1327 the top of the window. This action is so handy that some people make a
|
|
|
1328 separate key binding to do this. For example,
|
|
|
1329
|
|
|
1330 @example
|
|
|
1331 @group
|
|
|
1332 (defun line-to-top-of-window ()
|
|
|
1333 "Scroll current line to top of window.
|
|
|
1334 Replaces three keystroke sequence C-u 0 C-l."
|
|
|
1335 (interactive)
|
|
|
1336 (recenter 0))
|
|
|
1337
|
|
|
1338 (global-set-key [kp-multiply] 'line-to-top-of-window)
|
|
|
1339 @end group
|
|
|
1340 @end example
|
|
|
1341 @end deffn
|
|
|
1342
|
|
|
1343 @node Horizontal Scrolling
|
|
|
1344 @section Horizontal Scrolling
|
|
|
1345 @cindex horizontal scrolling
|
|
|
1346
|
|
|
1347 Because we read English first from top to bottom and second from left
|
|
|
1348 to right, horizontal scrolling is not like vertical scrolling. Vertical
|
|
|
1349 scrolling involves selection of a contiguous portion of text to display.
|
|
|
1350 Horizontal scrolling causes part of each line to go off screen. The
|
|
|
1351 amount of horizontal scrolling is therefore specified as a number of
|
|
|
1352 columns rather than as a position in the buffer. It has nothing to do
|
|
|
1353 with the display-start position returned by @code{window-start}.
|
|
|
1354
|
|
|
1355 Usually, no horizontal scrolling is in effect; then the leftmost
|
|
|
1356 column is at the left edge of the window. In this state, scrolling to
|
|
|
1357 the right is meaningless, since there is no data to the left of the
|
|
|
1358 screen to be revealed by it; so this is not allowed. Scrolling to the
|
|
|
1359 left is allowed; it scrolls the first columns of text off the edge of
|
|
|
1360 the window and can reveal additional columns on the right that were
|
|
|
1361 truncated before. Once a window has a nonzero amount of leftward
|
|
|
1362 horizontal scrolling, you can scroll it back to the right, but only so
|
|
|
1363 far as to reduce the net horizontal scroll to zero. There is no limit
|
|
|
1364 to how far left you can scroll, but eventually all the text will
|
|
|
1365 disappear off the left edge.
|
|
|
1366
|
|
|
1367 @deffn Command scroll-left count
|
|
|
1368 This function scrolls the selected window @var{count} columns to the
|
|
|
1369 left (or to the right if @var{count} is negative). The return value is
|
|
|
1370 the total amount of leftward horizontal scrolling in effect after the
|
|
|
1371 change---just like the value returned by @code{window-hscroll} (below).
|
|
|
1372 @end deffn
|
|
|
1373
|
|
|
1374 @deffn Command scroll-right count
|
|
|
1375 This function scrolls the selected window @var{count} columns to the
|
|
|
1376 right (or to the left if @var{count} is negative). The return value is
|
|
|
1377 the total amount of leftward horizontal scrolling in effect after the
|
|
|
1378 change---just like the value returned by @code{window-hscroll} (below).
|
|
|
1379
|
|
|
1380 Once you scroll a window as far right as it can go, back to its normal
|
|
|
1381 position where the total leftward scrolling is zero, attempts to scroll
|
|
|
1382 any farther right have no effect.
|
|
|
1383 @end deffn
|
|
|
1384
|
|
|
1385 @defun window-hscroll &optional window
|
|
|
1386 This function returns the total leftward horizontal scrolling of
|
|
|
1387 @var{window}---the number of columns by which the text in @var{window}
|
|
|
1388 is scrolled left past the left margin.
|
|
|
1389
|
|
|
1390 The value is never negative. It is zero when no horizontal scrolling
|
|
|
1391 has been done in @var{window} (which is usually the case).
|
|
|
1392
|
|
|
1393 If @var{window} is @code{nil}, the selected window is used.
|
|
|
1394
|
|
|
1395 @example
|
|
|
1396 @group
|
|
|
1397 (window-hscroll)
|
|
|
1398 @result{} 0
|
|
|
1399 @end group
|
|
|
1400 @group
|
|
|
1401 (scroll-left 5)
|
|
|
1402 @result{} 5
|
|
|
1403 @end group
|
|
|
1404 @group
|
|
|
1405 (window-hscroll)
|
|
|
1406 @result{} 5
|
|
|
1407 @end group
|
|
|
1408 @end example
|
|
|
1409 @end defun
|
|
|
1410
|
|
|
1411 @defun set-window-hscroll window columns
|
|
|
1412 This function sets the number of columns from the left margin that
|
|
|
1413 @var{window} is scrolled to the value of @var{columns}. The argument
|
|
|
1414 @var{columns} should be zero or positive; if not, it is taken as zero.
|
|
|
1415
|
|
|
1416 The value returned is @var{columns}.
|
|
|
1417
|
|
|
1418 @example
|
|
|
1419 @group
|
|
|
1420 (set-window-hscroll (selected-window) 10)
|
|
|
1421 @result{} 10
|
|
|
1422 @end group
|
|
|
1423 @end example
|
|
|
1424 @end defun
|
|
|
1425
|
|
|
1426 Here is how you can determine whether a given position @var{position}
|
|
|
1427 is off the screen due to horizontal scrolling:
|
|
|
1428
|
|
|
1429 @example
|
|
|
1430 @group
|
|
|
1431 (defun hscroll-on-screen (window position)
|
|
|
1432 (save-excursion
|
|
|
1433 (goto-char position)
|
|
|
1434 (and
|
|
|
1435 (>= (- (current-column) (window-hscroll window)) 0)
|
|
|
1436 (< (- (current-column) (window-hscroll window))
|
|
|
1437 (window-width window)))))
|
|
|
1438 @end group
|
|
|
1439 @end example
|
|
|
1440 @node Size of Window
|
|
|
1441 @section The Size of a Window
|
|
|
1442 @cindex window size
|
|
|
1443 @cindex size of window
|
|
|
1444
|
|
|
1445 An Emacs window is rectangular, and its size information consists of
|
|
|
1446 the height (in lines or pixels) and the width (in character positions
|
|
|
1447 or pixels). The modeline is included in the height. The pixel
|
|
|
1448 width and height values include scrollbars and margins, while the
|
|
|
1449 line/character-position values do not.
|
|
|
1450
|
|
|
1451 Note that the height in lines, and the width in characters, are
|
|
|
1452 determined by dividing the corresponding pixel value by the height or
|
|
|
1453 width of the default font in that window (if this is a variable-width
|
|
|
1454 font, the average width is used). The resulting values may or may not
|
|
|
1455 represent the actual number of lines in the window, or the actual number
|
|
|
1456 of character positions in any particular line, esp. if there are pixmaps
|
|
|
1457 or various different fonts in the window.
|
|
|
1458
|
|
|
1459 The following functions return size information about a window:
|
|
|
1460
|
|
|
1461 @defun window-height &optional window
|
|
|
1462 This function returns the number of lines in @var{window}, including
|
|
|
1463 its modeline but not including the horizontal scrollbar, if any (this
|
|
|
1464 is different from @code{window-pixel-height}). If @var{window} is
|
|
|
1465 @code{nil}, the function uses the selected window.
|
|
|
1466
|
|
|
1467 @example
|
|
|
1468 @group
|
|
|
1469 (window-height)
|
|
|
1470 @result{} 40
|
|
|
1471 @end group
|
|
|
1472 @group
|
|
|
1473 (split-window-vertically)
|
|
|
1474 @result{} #<window on "windows.texi" 0x679b>
|
|
|
1475 @end group
|
|
|
1476 @group
|
|
|
1477 (window-height)
|
|
|
1478 @result{} 20
|
|
|
1479 @end group
|
|
|
1480 @end example
|
|
|
1481 @end defun
|
|
|
1482
|
|
|
1483 @defun window-width &optional window
|
|
|
1484 This function returns the number of columns in @var{window}, not
|
|
|
1485 including any left margin, right margin, or vertical scrollbar (this is
|
|
|
1486 different from @code{window-pixel-width}). If @var{window} is
|
|
|
1487 @code{nil}, the function uses the selected window.
|
|
|
1488
|
|
|
1489 @example
|
|
|
1490 @group
|
|
|
1491 (window-width)
|
|
|
1492 @result{} 80
|
|
|
1493 @end group
|
|
|
1494 @group
|
|
|
1495 (window-height)
|
|
|
1496 @result{} 40
|
|
|
1497 @end group
|
|
|
1498 @group
|
|
|
1499 (split-window-horizontally)
|
|
|
1500 @result{} #<window on "windows.texi" 0x7538>
|
|
|
1501 @end group
|
|
|
1502 @group
|
|
|
1503 (window-width)
|
|
|
1504 @result{} 39
|
|
|
1505 @end group
|
|
|
1506 @end example
|
|
|
1507 @end defun
|
|
|
1508
|
|
|
1509 Note that after splitting the window into two side-by-side windows,
|
|
|
1510 the width of each window is less the half the width of the original
|
|
|
1511 window because a vertical scrollbar appeared between the windows,
|
|
|
1512 occupying two columns worth of space. Also, the height shrunk by
|
|
|
1513 one because horizontal scrollbars appeared that weren't there
|
|
|
1514 before. (Horizontal scrollbars appear only when lines are
|
|
|
1515 truncated, not when they wrap. This is usually the case for
|
|
|
1516 horizontally split windows but not for full-frame windows. You
|
|
|
1517 can change this using the variables @code{truncate-lines} and
|
|
|
1518 @code{truncate-partial-width-windows}.)
|
|
|
1519
|
|
|
1520 @defun window-pixel-height &optional window
|
|
|
1521 This function returns the height of @var{window} in pixels, including
|
|
|
1522 its modeline and horizontal scrollbar, if any. If @var{window} is
|
|
|
1523 @code{nil}, the function uses the selected window.
|
|
|
1524
|
|
|
1525 @example
|
|
|
1526 @group
|
|
|
1527 (window-pixel-height)
|
|
|
1528 @result{} 600
|
|
|
1529 @end group
|
|
|
1530 @group
|
|
|
1531 (split-window-vertically)
|
|
|
1532 @result{} #<window on "windows.texi" 0x68a6>
|
|
|
1533 @end group
|
|
|
1534 @group
|
|
|
1535 (window-pixel-height)
|
|
|
1536 @result{} 300
|
|
|
1537 @end group
|
|
|
1538 @end example
|
|
|
1539 @end defun
|
|
|
1540
|
|
|
1541 @defun window-pixel-width &optional window
|
|
|
1542 This function returns the width of @var{window} in pixels, including
|
|
|
1543 any left margin, right margin, or vertical scrollbar that may be
|
|
|
1544 displayed alongside it. If @var{window} is @code{nil}, the function
|
|
|
1545 uses the selected window.
|
|
|
1546
|
|
|
1547 @example
|
|
|
1548 @group
|
|
|
1549 (window-pixel-width)
|
|
|
1550 @result{} 735
|
|
|
1551 @end group
|
|
|
1552 @group
|
|
|
1553 (window-pixel-height)
|
|
|
1554 @result{} 600
|
|
|
1555 @end group
|
|
|
1556 @group
|
|
|
1557 (split-window-horizontally)
|
|
|
1558 @result{} #<window on "windows.texi" 0x7538>
|
|
|
1559 @end group
|
|
|
1560 @group
|
|
|
1561 (window-pixel-width)
|
|
|
1562 @result{} 367
|
|
|
1563 @end group
|
|
|
1564 @group
|
|
|
1565 (window-pixel-height)
|
|
|
1566 @result{} 600
|
|
|
1567 @end group
|
|
|
1568 @end example
|
|
|
1569 @end defun
|
|
|
1570
|
|
|
1571 @node Position of Window
|
|
|
1572 @section The Position of a Window
|
|
|
1573 @cindex window position
|
|
|
1574 @cindex position of window
|
|
|
1575
|
|
|
1576 XEmacs provides functions to determine the absolute location of windows
|
|
|
1577 within a frame, and the relative location of a window in comparison to
|
|
|
1578 other windows in the same frame.
|
|
|
1579
|
|
|
1580 @defun window-pixel-edges &optional window
|
|
|
1581 This function returns a list of the pixel edge coordinates of
|
|
|
1582 @var{window}. If @var{window} is @code{nil}, the selected window is
|
|
|
1583 used.
|
|
|
1584
|
|
|
1585 The order of the list is @code{(@var{left} @var{top} @var{right}
|
|
|
1586 @var{bottom})}, all elements relative to 0, 0 at the top left corner of
|
|
|
1587 the frame. The element @var{right} of the value is one more than the
|
|
|
1588 rightmost pixel used by @var{window} (including any left margin, right
|
|
|
1589 margin, or vertical scrollbar displayed alongside it), and
|
|
|
1590 @var{bottom} is one more than the bottommost pixel used by @var{window}
|
|
|
1591 (including any modeline or horizontal scrollbar displayed above
|
|
|
1592 or below it). The frame area does not include any frame menubars or
|
|
|
1593 toolbars that may be displayed; thus, for example, if there is only
|
|
|
1594 one window on the frame, the values for @var{left} and @var{top} will
|
|
|
1595 always be 0.
|
|
|
1596
|
|
|
1597 If @var{window} is at the upper left corner of its frame, @var{right}
|
|
|
1598 and @var{bottom} are the same as the values returned by
|
|
|
1599 @code{(window-pixel-width)} and @code{(window-pixel-height)}
|
|
|
1600 respectively, and @var{top} and @var{bottom} are zero.
|
|
|
1601 @end defun
|
|
|
1602
|
|
|
1603 There is no longer a function @code{window-edges} because it does not
|
|
|
1604 make sense in a world with variable-width and variable-height lines,
|
|
|
1605 as are allowed in XEmacs.
|
|
|
1606
|
|
|
1607 @defun window-highest-p window
|
|
|
1608 This function returns non-@code{nil} if @var{window} is along the
|
|
|
1609 top of its frame.
|
|
|
1610 @end defun
|
|
|
1611
|
|
|
1612 @defun window-lowest-p window
|
|
|
1613 This function returns non-@code{nil} if @var{window} is along the
|
|
|
1614 bottom of its frame.
|
|
|
1615 @end defun
|
|
|
1616
|
|
|
1617 @node Resizing Windows
|
|
|
1618 @section Changing the Size of a Window
|
|
|
1619 @cindex window resizing
|
|
|
1620 @cindex changing window size
|
|
|
1621 @cindex window size, changing
|
|
|
1622
|
|
|
1623 The window size functions fall into two classes: high-level commands
|
|
|
1624 that change the size of windows and low-level functions that access
|
|
|
1625 window size. XEmacs does not permit overlapping windows or gaps between
|
|
|
1626 windows, so resizing one window affects other windows.
|
|
|
1627
|
|
|
1628 @deffn Command enlarge-window size &optional horizontal
|
|
|
1629 This function makes the selected window @var{size} lines taller,
|
|
|
1630 stealing lines from neighboring windows. It takes the lines from one
|
|
|
1631 window at a time until that window is used up, then takes from another.
|
|
|
1632 If a window from which lines are stolen shrinks below
|
|
|
1633 @code{window-min-height} lines, that window disappears.
|
|
|
1634
|
|
|
1635 If @var{horizontal} is non-@code{nil}, this function makes
|
|
|
1636 @var{window} wider by @var{size} columns, stealing columns instead of
|
|
|
1637 lines. If a window from which columns are stolen shrinks below
|
|
|
1638 @code{window-min-width} columns, that window disappears.
|
|
|
1639
|
|
|
1640 If the requested size would exceed that of the window's frame, then the
|
|
|
1641 function makes the window occupy the entire height (or width) of the
|
|
|
1642 frame.
|
|
|
1643
|
|
|
1644 If @var{size} is negative, this function shrinks the window by
|
|
|
1645 @minus{}@var{size} lines or columns. If that makes the window smaller
|
|
|
1646 than the minimum size (@code{window-min-height} and
|
|
|
1647 @code{window-min-width}), @code{enlarge-window} deletes the window.
|
|
|
1648
|
|
|
1649 @code{enlarge-window} returns @code{nil}.
|
|
|
1650 @end deffn
|
|
|
1651
|
|
|
1652 @deffn Command enlarge-window-horizontally columns
|
|
|
1653 This function makes the selected window @var{columns} wider.
|
|
|
1654 It could be defined as follows:
|
|
|
1655
|
|
|
1656 @example
|
|
|
1657 @group
|
|
|
1658 (defun enlarge-window-horizontally (columns)
|
|
|
1659 (enlarge-window columns t))
|
|
|
1660 @end group
|
|
|
1661 @end example
|
|
|
1662 @end deffn
|
|
|
1663
|
|
|
1664 @deffn Command shrink-window size &optional horizontal
|
|
|
1665 This function is like @code{enlarge-window} but negates the argument
|
|
|
1666 @var{size}, making the selected window smaller by giving lines (or
|
|
|
1667 columns) to the other windows. If the window shrinks below
|
|
|
1668 @code{window-min-height} or @code{window-min-width}, then it disappears.
|
|
|
1669
|
|
|
1670 If @var{size} is negative, the window is enlarged by @minus{}@var{size}
|
|
|
1671 lines or columns.
|
|
|
1672 @end deffn
|
|
|
1673
|
|
|
1674 @deffn Command shrink-window-horizontally columns
|
|
|
1675 This function makes the selected window @var{columns} narrower.
|
|
|
1676 It could be defined as follows:
|
|
|
1677
|
|
|
1678 @example
|
|
|
1679 @group
|
|
|
1680 (defun shrink-window-horizontally (columns)
|
|
|
1681 (shrink-window columns t))
|
|
|
1682 @end group
|
|
|
1683 @end example
|
|
|
1684 @end deffn
|
|
|
1685
|
|
|
1686 @cindex minimum window size
|
|
|
1687 The following two variables constrain the window-size-changing
|
|
|
1688 functions to a minimum height and width.
|
|
|
1689
|
|
|
1690 @defopt window-min-height
|
|
|
1691 The value of this variable determines how short a window may become
|
|
|
1692 before it is automatically deleted. Making a window smaller than
|
|
|
1693 @code{window-min-height} automatically deletes it, and no window may be
|
|
|
1694 created shorter than this. The absolute minimum height is two (allowing
|
|
|
1695 one line for the mode line, and one line for the buffer display).
|
|
|
1696 Actions that change window sizes reset this variable to two if it is
|
|
|
1697 less than two. The default value is 4.
|
|
|
1698 @end defopt
|
|
|
1699
|
|
|
1700 @defopt window-min-width
|
|
|
1701 The value of this variable determines how narrow a window may become
|
|
|
1702 before it automatically deleted. Making a window smaller than
|
|
|
1703 @code{window-min-width} automatically deletes it, and no window may be
|
|
|
1704 created narrower than this. The absolute minimum width is one; any
|
|
|
1705 value below that is ignored. The default value is 10.
|
|
|
1706 @end defopt
|
|
|
1707
|
|
|
1708 @defvar window-size-change-functions
|
|
|
1709 This variable holds a list of functions to be called if the size of any
|
|
|
1710 window changes for any reason. The functions are called just once per
|
|
|
1711 redisplay, and just once for each frame on which size changes have
|
|
|
1712 occurred.
|
|
|
1713
|
|
|
1714 Each function receives the frame as its sole argument. There is no
|
|
|
1715 direct way to find out which windows changed size, or precisely how;
|
|
|
1716 however, if your size-change function keeps track, after each change, of
|
|
|
1717 the windows that interest you, you can figure out what has changed by
|
|
|
1718 comparing the old size data with the new.
|
|
|
1719
|
|
|
1720 Creating or deleting windows counts as a size change, and therefore
|
|
|
1721 causes these functions to be called. Changing the frame size also
|
|
|
1722 counts, because it changes the sizes of the existing windows.
|
|
|
1723
|
|
|
1724 It is not a good idea to use @code{save-window-excursion} in these
|
|
|
1725 functions, because that always counts as a size change, and it would
|
|
|
1726 cause these functions to be called over and over. In most cases,
|
|
|
1727 @code{save-selected-window} is what you need here.
|
|
|
1728 @end defvar
|
|
|
1729
|
|
|
1730 @node Window Configurations
|
|
|
1731 @section Window Configurations
|
|
|
1732 @cindex window configurations
|
|
|
1733 @cindex saving window information
|
|
|
1734
|
|
|
1735 A @dfn{window configuration} records the entire layout of a
|
|
|
1736 frame---all windows, their sizes, which buffers they contain, what part
|
|
|
1737 of each buffer is displayed, and the values of point and the mark. You
|
|
|
1738 can bring back an entire previous layout by restoring a window
|
|
|
1739 configuration previously saved.
|
|
|
1740
|
|
|
1741 If you want to record all frames instead of just one, use a frame
|
|
|
1742 configuration instead of a window configuration. @xref{Frame
|
|
|
1743 Configurations}.
|
|
|
1744
|
|
|
1745 @defun current-window-configuration
|
|
|
1746 This function returns a new object representing XEmacs's current window
|
|
|
1747 configuration, namely the number of windows, their sizes and current
|
|
|
1748 buffers, which window is the selected window, and for each window the
|
|
|
1749 displayed buffer, the display-start position, and the positions of point
|
|
|
1750 and the mark. An exception is made for point in the current buffer,
|
|
|
1751 whose value is not saved.
|
|
|
1752 @end defun
|
|
|
1753
|
|
|
1754 @defun set-window-configuration configuration
|
|
|
1755 This function restores the configuration of XEmacs's windows and
|
|
|
1756 buffers to the state specified by @var{configuration}. The argument
|
|
|
1757 @var{configuration} must be a value that was previously returned by
|
|
|
1758 @code{current-window-configuration}.
|
|
|
1759
|
|
|
1760 This function always counts as a window size change and triggers
|
|
|
1761 execution of the @code{window-size-change-functions}. (It doesn't know
|
|
|
1762 how to tell whether the new configuration actually differs from the old
|
|
|
1763 one.)
|
|
|
1764
|
|
|
1765 Here is a way of using this function to get the same effect
|
|
|
1766 as @code{save-window-excursion}:
|
|
|
1767
|
|
|
1768 @example
|
|
|
1769 @group
|
|
|
1770 (let ((config (current-window-configuration)))
|
|
|
1771 (unwind-protect
|
|
|
1772 (progn (split-window-vertically nil)
|
|
|
1773 @dots{})
|
|
|
1774 (set-window-configuration config)))
|
|
|
1775 @end group
|
|
|
1776 @end example
|
|
|
1777 @end defun
|
|
|
1778
|
|
|
1779 @defspec save-window-excursion forms@dots{}
|
|
|
1780 This special form records the window configuration, executes @var{forms}
|
|
|
1781 in sequence, then restores the earlier window configuration. The window
|
|
|
1782 configuration includes the value of point and the portion of the buffer
|
|
|
1783 that is visible. It also includes the choice of selected window.
|
|
|
1784 However, it does not include the value of point in the current buffer;
|
|
|
1785 use @code{save-excursion} if you wish to preserve that.
|
|
|
1786
|
|
|
1787 Don't use this construct when @code{save-selected-window} is all you need.
|
|
|
1788
|
|
|
1789 Exit from @code{save-window-excursion} always triggers execution of the
|
|
|
1790 @code{window-size-change-functions}. (It doesn't know how to tell
|
|
|
1791 whether the restored configuration actually differs from the one in
|
|
|
1792 effect at the end of the @var{forms}.)
|
|
|
1793
|
|
|
1794 The return value is the value of the final form in @var{forms}.
|
|
|
1795 For example:
|
|
|
1796
|
|
|
1797 @example
|
|
|
1798 @group
|
|
|
1799 (split-window)
|
|
|
1800 @result{} #<window 25 on control.texi>
|
|
|
1801 @end group
|
|
|
1802 @group
|
|
|
1803 (setq w (selected-window))
|
|
|
1804 @result{} #<window 19 on control.texi>
|
|
|
1805 @end group
|
|
|
1806 @group
|
|
|
1807 (save-window-excursion
|
|
|
1808 (delete-other-windows w)
|
|
|
1809 (switch-to-buffer "foo")
|
|
|
1810 'do-something)
|
|
|
1811 @result{} do-something
|
|
|
1812 ;; @r{The frame is now split again.}
|
|
|
1813 @end group
|
|
|
1814 @end example
|
|
|
1815 @end defspec
|
|
|
1816
|
|
|
1817 @defun window-configuration-p object
|
|
|
1818 This function returns @code{t} if @var{object} is a window configuration.
|
|
|
1819 @end defun
|
|
|
1820
|
|
|
1821 Primitives to look inside of window configurations would make sense,
|
|
|
1822 but none are implemented. It is not clear they are useful enough to be
|
|
|
1823 worth implementing.
|
