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/* pgmramp.c - generate a grayscale ramp
**
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation. This software is provided "as is" without express or
** implied warranty.
*/
#include <math.h>
#include "pm_c_util.h"
#include "pgm.h"
#include "shhopt.h"
enum ramptype {RT_LR, RT_TB, RT_DIAG, RT_RECT, RT_ELLIP};
struct cmdlineInfo {
/* All the information the user supplied in the command line,
in a form easy for the program to use.
*/
enum ramptype ramptype;
unsigned int cols;
unsigned int rows;
gray maxval;
};
static void
parseCommandLine(int argc, char ** argv,
struct cmdlineInfo * const cmdlineP) {
/*----------------------------------------------------------------------------
Convert program invocation arguments (argc,argv) into a format the
program can use easily, struct cmdlineInfo. Validate arguments along
the way and exit program with message if invalid.
Note that some string information we return as *cmdlineP is in the storage
argv[] points to.
-----------------------------------------------------------------------------*/
optEntry *option_def = malloc(100*sizeof(optEntry));
/* Instructions to OptParseOptions2 on how to parse our options.
*/
optStruct3 opt;
unsigned int lrSpec, tbSpec, diagonalSpec, rectangleSpec, ellipseSpec;
unsigned int maxvalSpec;
unsigned int option_def_index;
option_def_index = 0; /* incremented by OPTENTRY */
OPTENT3(0, "lr", OPT_FLAG, NULL, &lrSpec, 0);
OPTENT3(0, "tb", OPT_FLAG, NULL, &tbSpec, 0);
OPTENT3(0, "diagonal", OPT_FLAG, NULL, &diagonalSpec, 0);
OPTENT3(0, "rectangle", OPT_FLAG, NULL, &rectangleSpec, 0);
OPTENT3(0, "ellipse", OPT_FLAG, NULL, &ellipseSpec, 0);
OPTENT3(0, "maxval", OPT_UINT, &cmdlineP->maxval, &maxvalSpec, 0);
opt.opt_table = option_def;
opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */
opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */
pm_optParseOptions3(&argc, argv, opt, sizeof(opt), 0);
/* Uses and sets argc, argv, and some of *cmdlineP and others. */
free (option_def);
if (lrSpec + tbSpec + diagonalSpec + rectangleSpec + ellipseSpec == 0)
pm_error("You must specify one of "
"-lr, -tb, -diagonal, -rectangle, or -ellipse");
if (lrSpec + tbSpec + diagonalSpec + rectangleSpec + ellipseSpec > 1)
pm_error("You may specify at most one of "
"-lr, -tb, -diagonal, -rectangle, or -ellipse");
if (lrSpec)
cmdlineP->ramptype = RT_LR;
else if (tbSpec)
cmdlineP->ramptype = RT_TB;
else if (diagonalSpec)
cmdlineP->ramptype = RT_DIAG;
else if (rectangleSpec)
cmdlineP->ramptype = RT_RECT;
else if (ellipseSpec)
cmdlineP->ramptype = RT_ELLIP;
else
pm_error("INTERNAL ERROR - no ramp type option found");
if (!maxvalSpec)
cmdlineP->maxval = PGM_MAXMAXVAL;
else {
if (cmdlineP->maxval > PGM_OVERALLMAXVAL)
pm_error("The value you specified for -maxval (%u) is too big. "
"Max allowed is %u", cmdlineP->maxval, PGM_OVERALLMAXVAL);
if (cmdlineP->maxval < 1)
pm_error("You cannot specify 0 for -maxval");
}
if (argc-1 < 2)
pm_error("Need two arguments: width and height.");
else if (argc-1 > 2)
pm_error("Only two arguments allowed: width and height. "
"You specified %d", argc-1);
else {
cmdlineP->cols = pm_parse_width(argv[1]);
cmdlineP->rows = pm_parse_height(argv[2]);
}
}
static int
diffu(unsigned int const subtrahend,
unsigned int const subtractor) {
return (int)subtrahend - (int)subtractor;
/* (Not the conventional terminology, but better) */
}
int
main(int argc, char *argv[]) {
struct cmdlineInfo cmdline;
gray *grayrow;
unsigned int rowso2, colso2;
unsigned int row;
pgm_init( &argc, argv );
parseCommandLine(argc, argv, &cmdline);
colso2 = MAX(1, cmdline.cols / 2);
rowso2 = MAX(1, cmdline.rows / 2);
pgm_writepgminit(stdout, cmdline.cols, cmdline.rows, cmdline.maxval, 0);
grayrow = pgm_allocrow(cmdline.cols);
for (row = 0; row < cmdline.rows; ++row) {
unsigned int col;
for (col = 0; col < cmdline.cols; ++col) {
switch (cmdline.ramptype) {
case RT_LR:
/* Fill row buffer once. All rows are identical. */
if (row == 0)
grayrow[col] =
(float) col * cmdline.maxval / MAX(cmdline.cols-1, 1);
break;
case RT_TB:
grayrow[col] =
(float) row * cmdline.maxval / MAX(cmdline.rows-1, 1);
break;
case RT_DIAG:
grayrow[col] =
((float) col + row) * cmdline.maxval /
MAX((float) cmdline.cols + cmdline.rows-2, 1);
break;
case RT_RECT: {
float const r = fabs((float)diffu(rowso2, row)) / rowso2;
float const c = fabs((float)diffu(colso2, col)) / colso2;
grayrow[col] =
cmdline.maxval - (r + c) / 2.0 * cmdline.maxval;
} break;
case RT_ELLIP: {
float const r = fabs((float)diffu(rowso2, row)) / rowso2;
float const c = fabs((float)diffu(colso2, col)) / colso2;
float const v = MAX(0.0f, MIN(1.0f, SQR(r) + SQR(c)));
grayrow[col] = cmdline.maxval - v * cmdline.maxval;
} break;
}
}
pgm_writepgmrow(stdout, grayrow, cmdline.cols, cmdline.maxval, 0);
}
pgm_freerow(grayrow);
pm_close(stdout);
return 0;
}
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