/*
 * render.c
 *
 * Render a high dynamic range buffer in some sensible way
 *
 * (c) 2006-2011 Thomas White <taw@physics.org>
 *
 * Part of CrystFEL - crystallography with a FEL
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


#include <stdlib.h>
#include <math.h>
#include <stdint.h>


#include "hdf5-file.h"
#include "render.h"
#include "peaks.h"
#include "filters.h"
#include "utils.h"


static void render_rgb(double val, double max,
                       double *rp, double *gp, double *bp)
{
	int s;
	double p;
	double r, g, b;

	s = val / (max/6);
	p = fmod(val, max/6.0);
	p /= (max/6.0);

	r = 0.0;  g = 0.0;  b = 0.0;

	if ( (val < 0.0) ) {
		s = 0;
		p = 0;
	}
	if ( (val > max) ) {
		s = 6;
	}
	switch ( s ) {
		case 0 : {	/* Black to blue */
			r = 0;  g = 0;  b = p;
			break;
		}
		case 1 : {	/* Blue to pink */
			r = p;  g = 0;  b = 1.0;
			break;
		}
		case 2 : {	/* Pink to red */
			r = 1.0;  g = 0;  b = (1.0-p)*1.0;
			break;
		}
		case 3 : {	/* Red to Orange */
			r = 1.0;  g = 0.5*p;  b = 0;
			break;
		}
		case 4 : {	/* Orange to Yellow */
			r = 1.0;  g = 0.5 + 0.5*p;  b = 0;
			break;
		}
		case 5 : {	/* Yellow to White */
			r = 1.0;  g = 1.0;  b = 1.0*p;
			break;
		}
		case 6 : {	/* Pixel has hit the maximum value */
			r = 1.0;  g = 1.0;  b = 1.0;
			break;
		}
	}

	*rp = r;
	*gp = g;
	*bp = b;
}


static void render_ratio(double val, double max,
                         double *rp, double *gp, double *bp)
{
	if ( val <= 1.0 ) {
		render_rgb(val, 2.0, rp, gp, bp);
	} else {
		/* Your homework is to simplify this expression */
		val = ((val-1.0)/(max-1.0)) * (max/2.0) + max/2.0;
		render_rgb(val, max, rp, gp, bp);
	}
}


static void render_mono(double val, double max,
                        double *rp, double *gp, double *bp)
{
	double p;
	p = val / max;
	if ( val < 0.0 ) p = 0.0;
	if ( val > max ) p = 1.0;
	*rp = p;
	*gp = p;
	*bp = p;
}


static void render_invmono(double val, double max,
                           double *rp, double *gp, double *bp)
{
	double p;
	p = val / max;
	p = 1.0 - p;
	if ( val < 0.0 ) p = 1.0;
	if ( val > max ) p = 0.0;
	*rp = p;
	*gp = p;
	*bp = p;
}


void render_scale(double val, double max, int scale,
                  double *rp, double *gp, double *bp)
{
	switch ( scale ) {
	case SCALE_COLOUR :
		render_rgb(val, max, rp, gp, bp);
		break;
	case SCALE_MONO :
		render_mono(val, max, rp, gp, bp);
		break;
	case SCALE_INVMONO :
		render_invmono(val, max, rp, gp, bp);
		break;
	case SCALE_RATIO :
		render_ratio(val, max, rp, gp, bp);
		break;
	}
}