static char RCSid[] = "$Id: Scale.c,v 1.1 91/08/22 16:27:10 gnb Exp $"; 
/*
 * $Source: /export/data/sources/x/At/Plotter/RCS/Scale.c,v $
 * 
 * $Log:	Scale.c,v $
 * Revision 1.1  91/08/22  16:27:10  gnb
 * Initial revision
 * 
 * 
 */

/*

Copyright 1990,1991 by the Massachusetts Institute of Technology

All rights reserved.

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, and that the name of the Massachusetts
Institute of Technology (M.I.T.) not be used in advertising or publicity
pertaining to distribution of the software without specific, written
prior permission.

M.I.T. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
M.I.T. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

*/
#include <math.h>
#include <stdio.h>
#include <string.h>

#include <X11/StringDefs.h>

#ifdef _AtDevelopment_
#include "Scale.h"
#else
#include <At/Scale.h>
#endif

extern int strcasecmp P((const char *, const char *));

#define New(t) ((t *) XtMalloc(sizeof(t)))

static char *error_messages[] = {
     "AtScale:  No Error.",
     "AtScaleCalc: high bound is less than low bound.",
     "AtScaleCalc: high bound and low bound are too close together.",
     "AtScaleCalc: logarithmic scale must have positive bounds",
     "AtScaleCalc: unknown transform type.",
};

double _AtScaleAlmostZero = 1.0e-12;

static void AtScaleCalc P((AtScale *s));
static void AtScaleCalc(s)
AtScale *s;
{
     s->errorcode = SCALEERROR_NONE;
     
     if (s->high < s->low) {
	  s->errorcode = SCALEERROR_BOUNDLESS;
	  s->transform = AtTransformINVALID;
	  return;
     }
     
     if (s->high - s->low < _AtScaleAlmostZero) {
	  s->errorcode = SCALEERROR_BOUNDCLOSE;
	  s->transform = AtTransformINVALID;
	  return;
     }
     
     if ((s->transform == AtTransformLOG) && (s->low <= 0.0)) {
	  s->errorcode = SCALEERROR_LOGNEGATIVE;
	  s->transform = AtTransformINVALID;
	  return;
     }
     
     switch (s->transform) {
     case AtTransformLINEAR:
	  s->mult = (s->highpix - s->lowpix)/(s->high - s->low);
	  s->offset = s->low;
	  break;
     case AtTransformLOG:
	  s->offset = log10(s->low);
	  s->mult = (s->highpix - s->lowpix)/(log10(s->high) - s->offset);
	  break;
     default:
	  s->errorcode = SCALEERROR_NOTRANSFORM;
	  break;
     }
     return;
}


AtScale *AtScaleCreate(low, high, lowpix, highpix, transform)
double low, high;
int lowpix, highpix;
AtTransform transform; 
{
     AtScale *scale;
     
     scale = New(AtScale);
     scale->low = low;
     scale->high = high;
     scale->lowpix = lowpix;
     scale->highpix = highpix;
     scale->transform = transform;
     
     AtScaleCalc(scale);
     return scale;
}

AtScale *AtScaleCopy(s)
AtScale *s;
{
     AtScale *new;
     new = New(AtScale);
     *new = *s;
     return new;
}

void AtScaleDestroy(s)
AtScale *s;
{
     XtFree((char *)s);
}

int AtScaleUserToPixel(s, x)
AtScale *s;
double x;
{
     switch (s->transform) {
     case AtTransformLINEAR:
	  return (int)((x - s->offset) * s->mult) + s->lowpix;
     case AtTransformLOG:
	  return (int)((log10(x) - s->offset) * s->mult) + s->lowpix;
     case AtTransformINVALID:
	  return 0;
     default:
	  s->errorcode = SCALEERROR_NOTRANSFORM;
	  return 0;
     }
}


double AtScalePixelToUser(s, i)
AtScale *s;
int i;
{
     switch (s->transform) {
     case AtTransformLINEAR:
	  return (double)((i - s->lowpix) / s->mult) + s->offset;
     case AtTransformLOG:
	  return pow(((i - s->lowpix) / s->mult) + s->offset, 10.0);
     case AtTransformINVALID:
	  return 0.0;
     default:
	  s->errorcode = SCALEERROR_NOTRANSFORM;
	  return 0.0;
     }
}

void AtScaleResize(s, new_lowpix, new_highpix)
AtScale *s;
int new_lowpix, new_highpix;
{
     s->lowpix = new_lowpix;
     s->highpix = new_highpix;
     (void) AtScaleCalc(s);
}

void AtScaleRescale(s, new_low, new_high)
AtScale *s;
double new_low, new_high;
{
     s->low = new_low;
     s->high = new_high;
     (void) AtScaleCalc(s);
}

void AtScaleChangeTransform(s, t)
AtScale *s;
AtTransform t;
{
     s->transform = t;
     (void) AtScaleCalc(s);
}

char *AtScaleGetErrorMessage(s)
AtScale *s;
{
     if (s->errorcode < XtNumber(error_messages))
	  return error_messages[s->errorcode];
     else
	  return error_messages[0];
}


void AtCvtStringToTransform(args, num_args, from, to)
XrmValue *args;
Cardinal num_args;
XrmValue *from, *to;
{
     static AtTransform transform;
     
     transform = AtTransformINVALID;
     
     if (strcasecmp(from->addr, "linear") == 0)
	  transform = AtTransformLINEAR;
     else if ((strcasecmp(from->addr, "log") == 0) ||
	      (strcasecmp(from->addr, "logarithmic") == 0))
	  transform = AtTransformLOG;
     
     if (transform == AtTransformINVALID)
	  XtStringConversionWarning(from->addr, XtRTransform);
     else {
	  to->addr = (caddr_t) &transform;
	  to->size = sizeof(AtTransform);
     }
}

void AtRegisterTransformConverter()
{
     static Boolean registered = False;
     
     if (!registered) {
	  XtAddConverter(XtRString, XtRTransform, AtCvtStringToTransform,
			 NULL,0);
	  registered = True;
     }
     *RCSid = *RCSid;		/* keep gcc quiet */
}