91 lines
3.9 KiB
Groff
91 lines
3.9 KiB
Groff
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.\" $NetBSD: intro.5,v 1.8 2003/11/02 11:16:03 wiz Exp $
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.\"
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.\" Copyright (c) 1980, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)intro.5 8.1 (Berkeley) 6/4/93
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.\"
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.sh 1 "Character Output and Scrolling"
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.pp
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The character output policy deals with the following problems.
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First, where is the location of the cursor after a character is printed, and
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secondly, when does the screen scroll if scrolling is enabled.
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.pp
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In the normal case the characters are output as expected, with the cursor
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occupying the position of the next character to be output.
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However, when the
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cursor is on the last column of the line, the cursor will remain on that
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position after the last character on the line is output and will only assume
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the position on the next line when the next character (the first on the next
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line) is output.
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.pp
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Likewise, if scrolling is enabled, a scroll will be invoked only when the
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first character on he first line past the bottom line of the window is
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output.
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If scrolling is not enabled the chracters will to be output to the
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bottom right corner of the window which is the cursor location.
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.pp
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This policy allows consistent behavior of the cursor at the boundary
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conditions.
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Furthermore, it prevents a scroll from happening before it is
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actually needed (the old package used to scroll when the bottom right position
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was output a character).
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As a precedent, it models the
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.i xterm
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character output conventions.
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.sh 1 "Terminal State Handling"
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.pp
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The variable
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.Vn curses_termios
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contains the terminal state of the terminal.
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Certain historical routines return information:
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.Fn baudrate ,
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.Fn erasechar ,
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.Fn killchar ,
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and
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.Fn ospeed .
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These routines are obsolete and exist only for backward compatibility.
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If you wish to use the information in the
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.Vn curses_termios
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structure, you should use the
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\fItsetattr\fP(3)
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routines.
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.sh 1 "Subwindows"
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.pp
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Subwindows are windows which do not have an independent text structure,
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.i i.e. ,
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they are windows whose text is a subset of the text of a larger window: the
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.i parent
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window.
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One consequence of this is that changes to either the parent or the
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child window are destructive to the other,
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.i i.e. ,
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a change to the subwindow is also a change to the parent window and a change
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to the parent window in the region defined by the subwindow is implicitly a
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change to the subwindow as well.
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Apart from this detail, subwindows function like any other window.
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