postmd.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
 *
 * postmd - matrix display program for PostScript printers.
 *
 * A simple program that can be used to display a matrix as a gray scale image on
 * a PostScript printer using the image operator. Much of the code was borrowed
 * from postdmd, the bitmap display program DMD screen dumps. May help if you have
 * a large matix (of floating point numbers) and want a simple way to look for
 * patterns.
 *
 * Matrix elements are a series of floating point numbers arranged in the input
 * file in row major order. The actual matrix elements can be preceeded by a simple
 * header that sets things like the matrix dimensions, interval list, and possibly
 * a window into the matrix that we'll use for display. The dimension statement is
 * perhaps the most important. If present it determines the number of rows and
 * columns in the matrix. For example, either of the following defines a 50x50
 * matrix,
 *
 *		dimension	50
 *		dimension	50x50
 *
 * If no dimension statement appears in the input file, the matrix is assumed to
 * be square, and the number of rows (and columns) is set to the square root of
 * the number of elements in the input file.
 *
 * Each matrix element is mapped into an integer in the range 0 to 255 (actually
 * 254) and PostScript's image operator then maps that number into a gray scale
 * appropriate for the particular printer. The mapping from the floating point
 * matrix elements to integers is accomplished using an interval list that can be
 * set using the -i option. The format of the interval string is,
 *
 *		num1,num2,num3,...,numn
 *
 * where each num is a floating point number. The list must be given in increasing
 * numerical order. A list of n numbers partitions the real line into 2n+1 regions
 * given as,
 *
 *		region1		element < num1
 *		region2		element = num1
 *		region3		element < num2
 *		region4		element = num2
 *		   .
 *		   .
 *		   .
 *		region2n	element = numn
 *		region2n+1	element > numn
 *
 * Every number in a region is mapped one integer in the range 0 to 254, and that
 * number, when displayed on a printer using the image operator, prints as a square
 * filled with a gray shade that reflects the integer that was chosen. 0 maps to
 * black and 255 maps to white (which by default will not be used).
 *
 * The default gray scale gets darker as the region number increases, but can be
 * changed by supplying a gray scale list with the -g option or in the optional
 * matrix header. The color map is again a comman or space separated list that
 * looks like,
 *
 *		color1,color2, ... ,color2n+1
 *
 * where color1 applies to region 1 and color2n+1 applies to region2n+1. Each
 * number in the list should be an integer between 0 and 255. If less than 2n+1
 * colors are given default assignments will be used for missing regions.
 *
 * The size of the matrix that we can display reasonably well is a function of the
 * number of elements in the interval list, paper size, and printer resolution.
 * For example a 300dpi printer using 8.5x11 inch paper gives us an image area of
 * about 2400x2400 pixels. An interval list of two numbers generates five separate
 * regions and will therefore need that many different shades of gray. Since we're
 * not using white we'll need to partion our image area into 4x4 pixel squares,
 * and that means a 600x600 matrix is about as big as we can go. In practice that's
 * optimistic, but the argument illustrates some of the limitations.
 *
 * A submatrix can be selected to display by windowing into the matrix. The window
 * list can be given using the -w option or can be set in the optional header that
 * can preceed each matrix.  The list should be a comma or space separated list
 * that looks like,
 *
 *		lower-column, lower-row, upper-column, upper-row
 *
 * where each element in the list must be a positive integer. Rows and columns in
 * the input matrix start at 1. The dimension of the displayed window will be from
 * lower-column to upper-column and from lower-row to upper-row inclusive.
 *
 * The encoding produced by the program is essentially identical to what's done
 * by postdmd. See the comments at the beginning of that program if you need more
 * details. The prologue also shares much of the same code. 
 *
 * The PostScript prologue is copied from *prologue before any of the input files
 * are translated. The program expects that the following PostScript procedures
 * are defined in that file:
 *
 *	setup
 *
 *	  mark ... setup -
 *
 *	    Handles special initialization stuff that depends on how this program
 *	    was called. Expects to find a mark followed by key/value pairs on the
 *	    stack. The def operator is applied to each pair up to the mark, then
 *	    the default state is set up.
 *
 *	pagesetup
 *
 *	  page pagesetup -
 *
 *	    Does whatever is needed to set things up for the next page. Expects
 *	    to find the current page number on the stack.
 *
 *	bitmap
 *
 *	  columns rows bitmap -
 *
 *	    Prints the image that's read as a hex string from standard input. The
 *	    image consists of rows lines, each of which includes columns elements.
 *	    Eight bits per pixel are used to encode the matrix elements.
 *
 *	labelmatrix
 *
 *	  matrixname matrixlimits labelmatrix -
 *
 *	    Prints string matrixname just below the lower left corner of the image
 *	    and prints string martixlimits near the lower right corner. Outlines
 *	    the entire image with a (one pixel wide) box and then draws tick marks
 *	    along the top and left sides of the image. One tick mark is printed
 *	    for every ten elements.
 *
 *	legend
 *
 *	  n1 ... nN N c1 m1 ... cM mM total regions legend -
 *
 *	    Prints the legend as a bar graph below the matrix image. n1 ... nN are
 *	    strings that represent the interval list. c1 m1 ... cm mM are pairs
 *	    that consist of a region's color and the statistics count. Actually
 *	    the c's are trivial procedures that just leave a one character string
 *	    on the stack when they're executed by image - which is the way the
 *	    bar graph is drawn.
 *
 *	done
 *
 *	  done
 *
 *	    Makes sure the last page is printed. Only needed when we're printing
 *	    more than one page on each sheet of paper.
 *
 * Many default values, like the magnification and orientation, are defined in 
 * the prologue, which is where they belong. If they're changed (by options), an
 * appropriate definition is made after the prologue is added to the output file.
 * The -P option passes arbitrary PostScript through to the output file. Among
 * other things it can be used to set (or change) values that can't be accessed by
 * other options.
 *
 */

#include <stdio.h>
#include <signal.h>
#include <ctype.h>
#ifdef plan9
#define	isascii(c)	((unsigned char)(c)<=0177)
#endif
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>

#include "comments.h"			/* PostScript file structuring comments */
#include "gen.h"			/* general purpose definitions */
#include "path.h"			/* for the prologue */
#include "ext.h"			/* external variable declarations */
#include "postmd.h"			/* special matrix display definitions */

char	*optnames = "a:b:c:d:g:i:m:n:o:p:w:x:y:A:C:E:J:L:P:R:DI";

char	*prologue = POSTMD;		/* default PostScript prologue */
char	*formfile = FORMFILE;		/* stuff for multiple pages per sheet */
char	*temp_dir = TEMPDIR;		/* temp directory for copying stdin */

int	formsperpage = 1;		/* page images on each piece of paper */
int	copies = 1;			/* and this many copies of each sheet */
int	bytespp = 6;			/* bytes per pattern - on output */

int	dostats = ON;			/* permanent statistics flag */
int	nxtstat = ON;			/* and the one for the next matrix */

char	*interval = DFLTILIST;		/* string representations of the interval */
char	*colormap = NULL;		/* color map */
char	*window = NULL;			/* and window lists */
char	*matrixname = "pipe.end";	/* name for the next plot */

Ilist	ilist[128];			/* active interval list and color map */
int	next = 0;			/* one past the last element in ilist[] */
int	regions;			/* an index assigned to the last region */
int	wlist[4];			/* upper left and lower right corners */

int	page = 0;			/* last page we worked on */
int	printed = 0;			/* and the number of pages printed */

int	dfltrows = 0;			/* default rows */
int	dfltcols = 0;			/* and columns - changed by -d option */
int	rows;				/* real number of rows */
int	columns;			/* and columns in the matrix */
int	patcount = 0;			/* will be set to columns * rows */

double	element;			/* next matrix element */

char	*raster = NULL;			/* next raster line */
char	*rptr;				/* next free byte in raster */
char	*eptr;				/* one past the last byte in raster */

FILE	*fp_in = stdin;			/* read from this file */
FILE	*fp_out = stdout;		/* and write stuff here */
FILE	*fp_acct = NULL;		/* for accounting data */

/*****************************************************************************/

main(agc, agv)

    int		agc;
    char	*agv[];

{

/*
 *
 * Bitmap display program for matrices. Only one matrix is allowed per input file,
 * and each one will be displayed on a page by itself. Input files consist of an
 * optional header followed by floating point numbers that represent the matrix
 * elements - in row major order.
 *
 */

    argc = agc;				/* other routines may want them */
    argv = agv;

    prog_name = argv[0];		/* really just for error messages */

    init_signals();			/* sets up interrupt handling */
    header();				/* PostScript header comments */
    options();				/* handle the command line options */
    setup();				/* for PostScript */
    arguments();			/* followed by each input file */
    done();				/* print the last page etc. */
    account();				/* job accounting data */

    exit(x_stat);			/* not much could be wrong */

}   /* End of main */

/*****************************************************************************/

init_signals()

{

/*
 *
 * Make sure we handle interrupts.
 *
 */

    if ( signal(SIGINT, interrupt) == SIG_IGN )  {
	signal(SIGINT, SIG_IGN);
	signal(SIGQUIT, SIG_IGN);
	signal(SIGHUP, SIG_IGN);
    } else {
	signal(SIGHUP, interrupt);
	signal(SIGQUIT, interrupt);
    }   /* End else */

    signal(SIGTERM, interrupt);
    signal(SIGFPE, interrupt);

}   /* End of init_signals */

/*****************************************************************************/

header()

{

    int		ch;			/* return value from getopt() */
    int		old_optind = optind;	/* for restoring optind - should be 1 */

/*
 *
 * Scans the option list looking for things, like the prologue file, that we need
 * right away but could be changed from the default. Doing things this way is an
 * attempt to conform to Adobe's latest file structuring conventions. In particular
 * they now say there should be nothing executed in the prologue, and they have
 * added two new comments that delimit global initialization calls. Once we know
 * where things really are we write out the job header, follow it by the prologue,
 * and then add the ENDPROLOG and BEGINSETUP comments.
 *
 */

    while ( (ch = getopt(argc, argv, optnames)) != EOF )
	if ( ch == 'L' )
	    prologue = optarg;
	else if ( ch == '?' )
	    error(FATAL, "");

    optind = old_optind;		/* get ready for option scanning */

    fprintf(stdout, "%s", CONFORMING);
    fprintf(stdout, "%s %s\n", VERSION, PROGRAMVERSION);
    fprintf(stdout, "%s %s\n", DOCUMENTFONTS, ATEND);
    fprintf(stdout, "%s %s\n", PAGES, ATEND);
    fprintf(stdout, "%s", ENDCOMMENTS);

    if ( cat(prologue) == FALSE )
	error(FATAL, "can't read %s", prologue);

    fprintf(stdout, "%s", ENDPROLOG);
    fprintf(stdout, "%s", BEGINSETUP);
    fprintf(stdout, "mark\n");

}   /* End of header */

/*****************************************************************************/

options()

{

    int		ch;			/* return value from getopt() */

/*
 *
 * Reads and processes the command line options. Added the -P option so arbitrary
 * PostScript code can be passed through. Expect it could be useful for changing
 * definitions in the prologue for which options have not been defined.
 *
 */

    while ( (ch = getopt(argc, argv, optnames)) != EOF )  {
	switch ( ch )  {
	    case 'a':			/* aspect ratio */
		    fprintf(stdout, "/aspectratio %s def\n", optarg);
		    break;

	    case 'b':			/* bytes per pattern - on output */
		    bytespp = atoi(optarg);
		    break;

	    case 'c':			/* copies */
		    copies = atoi(optarg);
		    fprintf(stdout, "/#copies %s store\n", optarg);
		    break;

	    case 'd':			/* default matrix dimensions */
		    sscanf(optarg, "%dx%d", &dfltrows, &dfltcols);
		    break;

	    case 'g':			/* set the colormap (ie. grayscale) */
		    colormap = optarg;
		    break;

	    case 'i':			/* matrix element interval list */
		    interval = optarg;
		    break;

	    case 'm':			/* magnification */
		    fprintf(stdout, "/magnification %s def\n", optarg);
		    break;

	    case 'n':			/* forms per page */
		    formsperpage = atoi(optarg);
		    fprintf(stdout, "%s %s\n", FORMSPERPAGE, optarg);
		    fprintf(stdout, "/formsperpage %s def\n", optarg);
		    break;

	    case 'o':			/* output page list */
		    out_list(optarg);
		    break;

	    case 'p':			/* landscape or portrait mode */
		    if ( *optarg == 'l' )
			fprintf(stdout, "/landscape true def\n");
		    else fprintf(stdout, "/landscape false def\n");
		    break;

	    case 'w':			/* set the window */
		    window = optarg;
		    break;

	    case 'x':			/* shift things horizontally */
		    fprintf(stdout, "/xoffset %s def\n", optarg);
		    break;