lut.c
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- /* $Id: lut.c,v 1.1.1.1 2005/11/11 21:32:03 faxguy Exp $ */
- /*
- * Copyright (c) 1990-1996 Sam Leffler
- * Copyright (c) 1991-1996 Silicon Graphics, Inc.
- * HylaFAX is a trademark of Silicon Graphics
- *
- * Permission to use, copy, modify, distribute, and sell this software and
- * its documentation for any purpose is hereby granted without fee, provided
- * that (i) the above copyright notices and this permission notice appear in
- * all copies of the software and related documentation, and (ii) the names of
- * Sam Leffler and Silicon Graphics may not be used in any advertising or
- * publicity relating to the software without the specific, prior written
- * permission of Sam Leffler and Silicon Graphics.
- *
- * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
- * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
- *
- * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
- * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
- * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
- * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
- * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
- * OF THIS SOFTWARE.
- */
- #include "lut.h"
- float frand();
- lut *makelut(func,insteps,outsteps,stoclut)
- float (*func)();
- int insteps, outsteps, stoclut;
- {
- lut *l;
- int i;
- float low, high, inspace;
- l = (lut *)malloc(sizeof(lut));
- l->insteps = insteps;
- l->outsteps = outsteps;
- l->stoclut = stoclut;
- if(stoclut) {
- l->flow = (float *)malloc(insteps*sizeof(float));
- l->fhigh = (float *)malloc(insteps*sizeof(float));
- inspace = insteps-1.0;
- for(i=0; i<insteps; i++) {
- low = (i-0.5)/inspace;
- high = (i+0.5)/inspace;
- if(low<0.0)
- low = 0.0;
- if(high>1.0)
- high = 1.0;
- l->flow[i] = (func)(low);
- l->fhigh[i] = (func)(high);
- }
- } else {
- l->stab = (unsigned short *)malloc(insteps*sizeof(unsigned short));
- inspace = insteps-1.0;
- for(i=0; i<insteps; i++)
- l->stab[i] = (l->outsteps-1)*(func)(i/inspace)+0.5;
- }
- return l;
- }
- applylut(l,sptr,n)
- lut *l;
- unsigned short *sptr;
- int n;
- {
- float delta, val;
- float *fhigh, *flow;
- unsigned short *stab;
- float outspace;
- int ival;
- if(l->stoclut) {
- fhigh = l->fhigh;
- flow = l->flow;
- outspace = l->outsteps-1;
- while(n--) {
- delta = fhigh[*sptr]-flow[*sptr];
- val = outspace*(flow[*sptr]+frand()*delta);
- ival = val;
- if((val-ival)<frand())
- *sptr++ = ival;
- else
- *sptr++ = ival+1;
- }
- } else {
- stab = l->stab;
- while(n--) {
- *sptr = stab[*sptr];
- sptr++;
- }
- }
- }
- void freelut(lut* l)
- {
- if(l->stoclut) {
- free((char*)l->flow);
- free((char*)l->fhigh);
- } else {
- free((char*)l->stab);
- }
- free((char*)l);
- }