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/*
* @(#)$Id: xy.c,v 1.6 2005/06/28 21:28:39 baccala Exp $
*
* Copyright (C) 1996 - 1999 Tim Witham <twitham@quiknet.com>
*
* (see the files README and COPYING for more details)
*
* xoscope external math filter command example (xy mode) in C.
*
* See operl for an example that can do arbitrary math at run-time.
*
* An external oscope command must continuously read two shorts from
* stdin and write one short to stdout. It must exit when stdin
* closes. The two shorts read in are the current input samples from
* channel 1 & 2. The short written out should be the desired math
* function result.
*
* This example provides an X-Y display window as an external command.
*
* usage: xy [samples]
*
* The command-line argument is the number of samples per screenful.
* You may need to use this if you resize the window. (default = 640)
*
*/
#include <unistd.h>
#include <stdlib.h>
#include "config.h"
#include "display.h"
int mode = 2, h_points = 640;
/* handle single key commands */
void
handle_key(char c)
{
switch (c) {
case '\e': /* Esc */
exit(0);
break;
case '\r': /* Enter */
case '\n':
clear();
break;
case '!':
mode++; /* point, point accumulate, line, line acc. */
if (mode > 3)
mode = 0;
clear();
break;
}
}
/* get and plot one screen full of data */
void
animate(void *data)
{
static short x, y, z = 0, X, Y, buff[sizeof(short)];
static int i, j;
if (!(mode % 2))
clear();
for (j = 0 ; j < h_points ; j++) {
/* Read two shorts from stdin (channel 1 & 2 */
if ((i = read(0, buff, sizeof(short))) != sizeof(short))
exit(i);
x = (short)(*buff); /* get channel 1 sample, increment pointer */
if ((i = read(0, buff, sizeof(short))) != sizeof(short))
exit(i);
y = (short)(*buff); /* get channel 2 sample, increment pointer */
if ((i = write(1, &z, sizeof(short))) != sizeof(short))
exit(i); /* write one short to stdout */
if (mode < 2)
DrawPixel(128 + x, 127 - y);
else if (j)
DrawLine(128 + X, 127 - Y, 128 + x, 127 - y);
X = x; Y = y;
}
SyncDisplay();
AddTimeOut(MSECREFRESH, animate, NULL);
}
int
main(int argc, char **argv) /* main program */
{
if ((argc = OpenDisplay(argc, argv)) == 0)
exit(1);
if (argc > 1)
h_points = strtol(argv[1], NULL, 0);
init_widgets();
clear();
animate(NULL);
MainLoop();
exit(0);
}
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