130 lines
4.7 KiB
C
130 lines
4.7 KiB
C
.\" $NetBSD: appen.C,v 1.5 1999/07/02 16:11:14 simonb Exp $
|
|
.\"
|
|
.\" Copyright (c) 1980, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)appen.C 8.1 (Berkeley) 6/8/93
|
|
.\"
|
|
.ie t .oh '\*(Ln Appendix A''PS1:19-%'
|
|
.eh 'PS1:19-%''\*(Ln Appendix A'
|
|
.el .he ''\fIAppendix A\fR''
|
|
.bp
|
|
.(x
|
|
.ti 0
|
|
.b "Appendix A"
|
|
.)x
|
|
.sh 1 "Examples" 1
|
|
.pp
|
|
Here we present a few examples
|
|
of how to use the package.
|
|
They attempt to be representative,
|
|
though not comprehensive. Further examples can be found in the games section
|
|
of the source tree and in various utilities that use the screen such as
|
|
.i systat(1) .
|
|
.sh 2 "Screen Updating"
|
|
.pp
|
|
The following examples are intended to demonstrate
|
|
the basic structure of a program
|
|
using the screen updating sections of the package.
|
|
Several of the programs require calculational sections
|
|
which are irrelevant of to the example,
|
|
and are therefore usually not included.
|
|
It is hoped that the data structure definitions
|
|
give enough of an idea to allow understanding
|
|
of what the relevant portions do.
|
|
.sh 3 "Simple Character Output"
|
|
.pp
|
|
This program demonstrates how to set up a window and output characters to it.
|
|
Also, it demonstrates how one might control the output to the window. If
|
|
you run this program, you will get a demonstration of the character output
|
|
chracteristics discussed in the above Character Output section.
|
|
.(l I
|
|
.so t2.gr
|
|
.)l
|
|
.sh 3 "A Small Screen Manipulator"
|
|
.pp
|
|
The next example follows the lines of the previous one but extends then to
|
|
demonstrate the various othe uses of the package. Make sure you understand
|
|
how this program works as it encompasses most of anything you will
|
|
need to do with the package.
|
|
.(l I
|
|
.so t3.gr
|
|
.)l
|
|
.sh 3 "Twinkle"
|
|
.pp
|
|
This is a moderately simple program which prints
|
|
patterns on the screen.
|
|
It switches between patterns of asterisks,
|
|
putting them on one by one in random order,
|
|
and then taking them off in the same fashion.
|
|
It is more efficient to write this
|
|
using only the motion optimization,
|
|
as is demonstrated below.
|
|
.(l I
|
|
.so twinkle1.gr
|
|
.)l
|
|
.sh 3 "Life"
|
|
.pp
|
|
This program fragment models the famous computer pattern game of life
|
|
(Scientific American, May, 1974).
|
|
The calculational routines create a linked list of structures
|
|
defining where each piece is.
|
|
Nothing here claims to be optimal,
|
|
merely demonstrative.
|
|
This code, however,
|
|
is a very good place to use the screen updating routines,
|
|
as it allows them to worry about what the last position looked like,
|
|
so you don't have to.
|
|
It also demonstrates some of the input routines.
|
|
.(l I
|
|
.so life.gr
|
|
.)l
|
|
.sh 2 "Motion optimization"
|
|
.pp
|
|
The following example shows how motion optimization
|
|
is written on its own.
|
|
Programs which flit from one place to another without
|
|
regard for what is already there
|
|
usually do not need the overhead of both space and time
|
|
associated with screen updating.
|
|
They should instead use motion optimization.
|
|
.sh 3 "Twinkle"
|
|
.pp
|
|
The
|
|
.b twinkle
|
|
program
|
|
is a good candidate for simple motion optimization.
|
|
Here is how it could be written
|
|
(only the routines that have been changed are shown):
|
|
.(l
|
|
.so twinkle2.gr
|
|
.)l
|