/*
 * render.c
 *
 * Render a high dynamic range buffer in some sensible way
 *
 * (c) 2008-2009 Thomas White <taw27@cam.ac.uk>
 *
 *  hdfileview - view Ditabis Micron images
 *
 */

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

#include <stdlib.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <math.h>
#include <stdint.h>

#include "hdf5-file.h"

/* Set to 1 to measure mean intensity in a rectangle */
#define MEASURE_INT 0

#define RENDER_RGB							       \
									       \
	int s;								       \
	float p;							       \
									       \
	s = val / (max/6);						       \
	p = fmod(val, max/6);						       \
	p /= (max/6);							       \
									       \
	r = 0;	g = 0;	b = 0;						       \
									       \
	switch ( s ) {							       \
		case 0 : {	/* Black to blue */			       \
			r = 0;		g = 0;			b = p*255;     \
			break;						       \
		}							       \
		case 1 : {	/* Blue to green */			       \
			r = 0;		g = 255*p;		b = (1-p)*255; \
			break;						       \
		}							       \
		case 2 : {	/* Green to red */			       \
			r =p*255;	g = (1-p)*255;		b = 0;	       \
			break;						       \
		}							       \
		case 3 : {	/* Red to Orange */			       \
			r = 255;	g = 127*p;		b = 0;	       \
			break;						       \
		}							       \
		case 4 : {	/* Orange to Yellow */			       \
			r = 255;	g = 127 + 127*p;	b = 0;	       \
			break;						       \
		}							       \
		case 5 : {	/* Yellow to White */			       \
			r = 255;	g = 255;		b = 255*p;     \
			break;						       \
		}							       \
		case 6 : {	/* Pixel has hit the maximum value */	       \
			r = 255;	g = 255;		b = 255;       \
			break;						       \
		}							       \
		default : {	/* Above saturation */			       \
			r = 255;	g = 255;		b = 255;       \
			break;						       \
		}							       \
	}

#define RENDER_MONO							       \
	float p;							       \
	p = (float)val / (float)max;					       \
	r = 255.0*p;	g = 255.0*p;	b = 255.0*p;

/* NB This function is shared between render_get_image() and
 * render_get_colour_scale() */
static void render_free_data(guchar *data, gpointer p)
{
	free(data);
}

/* Return a pixbuf containing a rendered version of the image after binning.
 * This pixbuf might be scaled later - hopefully mostly in a downward
 * direction. */
GdkPixbuf *render_get_image(struct hdfile *hdfile, int binning, int boostint,
			    int monochrome)
{
	int mw, mh, w, h;
	guchar *data;
	int16_t *hdr;
	size_t x, y;
	int16_t max;

	mw = hdfile_get_width(hdfile);
	mh = hdfile_get_height(hdfile);
	w = mw / binning;
	h = mh / binning;

	/* High dynamic range version */
	hdr = hdfile_get_image_binned(hdfile, binning, &max);
	if ( hdr == NULL ) return NULL;

	/* Rendered (colourful) version */
	data = malloc(3*w*h);
	if ( data == NULL ) {
		free(hdr);
		return NULL;
	}

	max /= boostint;
	if ( max <= 6 ) { max = 10; }
	/* These x,y coordinates are measured relative to the bottom-left
	 * corner */
	for ( y=0; y<h; y++ ) {
	for ( x=0; x<w; x++ ) {

		int val;
		guchar r, g, b;

		val = hdr[x+w*y];
		if ( !monochrome ) {
			RENDER_RGB
		} else {
			RENDER_MONO
		}

		/* Stuff inside square brackets makes this pixel go to
		 * the expected location in the pixbuf (which measures
		 * from the top-left corner */
		data[3*( x+w*(h-1-y) )+0] = r;
		data[3*( x+w*(h-1-y) )+1] = g;
		data[3*( x+w*(h-1-y) )+2] = b;

	}
	}

	/* Finished with this */
	free(hdr);

	/* Create the pixbuf from the 8-bit display data */
	return gdk_pixbuf_new_from_data(data, GDK_COLORSPACE_RGB, FALSE, 8,
					w, h, w*3, render_free_data, NULL);
}

GdkPixbuf *render_get_colour_scale(size_t w, size_t h, int monochrome)
{
	guchar *data;
	size_t x, y;
	int max;

	data = malloc(3*w*h);
	if ( data == NULL ) return NULL;

	max = h;

	for ( y=0; y<h; y++ ) {

		guchar r, g, b;
		int val;

		val = y;
		if ( !monochrome ) {
			RENDER_RGB
		} else {
			RENDER_MONO
		}

		data[3*( 0+w*(h-1-y) )+0] = 0;
		data[3*( 0+w*(h-1-y) )+1] = 0;
		data[3*( 0+w*(h-1-y) )+2] = 0;
		for ( x=1; x<w; x++ ) {
			data[3*( x+w*(h-1-y) )+0] = r;
			data[3*( x+w*(h-1-y) )+1] = g;
			data[3*( x+w*(h-1-y) )+2] = b;
		}

	}

	return gdk_pixbuf_new_from_data(data, GDK_COLORSPACE_RGB, FALSE, 8,
					w, h, w*3, render_free_data, NULL);
}