/* Floating-point color images, and image files in PPM format */
/* Last edited on 2007-11-07 11:59:58 by stolfi */ 

#ifndef frgb_image_H
#define frgb_image_H

/* TO DO: uniformize names, fields, procs with {float_image.h}. */

#include <frgb.h>
#include <stdio.h>
#include <nat.h>
#include <bool.h>

typedef struct { nat_t NX, NY; frgb_t **pix; } frgb_image_t; 

/* MAIN PROCEDURES */

frgb_image_t  frgb_image_new (nat_t NX, nat_t NY);
  /*
    Allocates a new color image of width NX and height NY. */

frgb_image_t  frgb_image_read_ppm (FILE *f, float gamma);
  /*
    Reads a PPM image (P6 or P3) from file "f". */

void  frgb_image_write_ppm (FILE *f, float gamma, frgb_image_t im);
  /*
    Writes an image to disk in raw PPM (P6) format. */
    
void  frgb_image_normalize (frgb_image_t im);
  /*
    Maps the colors of all pixels to fit in the [0..1] cube, by scaling 
    uniformly the three components and and adding or subtracting a constant
    amount of white.  This transformation preserves hue, and
    rescales brightness and chroma independently of each other.
    So grays remain gray, and equally bright colors remain equally 
    bright. */

/* LOW-LEVEL PROCEDURES */

void  frgb_image_read_ppm_header (FILE *f, nat_t *NX, nat_t *NY, nat_t *maxval, bool_t *raw);
  /* 
    Reads the header of a PPM image (P6 or P3), returnd header data.
    The "raw" bit is TRUE for binary pixels (P6), FALSE for ascii (P3). */

void frgb_image_read_ppm_raw_pixels (FILE *f, nat_t maxval, float gamma, nat_t NX, frgb_t px[]);
void frgb_image_read_ppm_ascii_pixels (FILE *f, nat_t maxval, float gamma, nat_t NX, frgb_t pix[]);
  /*
    Reads one row of pixels from file "f" */
    
void frgb_image_write_ppm_header (FILE *f, nat_t NX, nat_t NY, nat_t maxval, bool_t raw);
  /* 
    Writes the header of a PPM image (P6 or P3). */

void frgb_image_write_ppm_raw_pixels (FILE *f, nat_t maxval, float gamma, nat_t NX, frgb_t pix[]);
void frgb_image_write_ppm_ascii_pixels (FILE *f, nat_t maxval, float gamma, nat_t NX, frgb_t pix[]);
  /*
    Writes one row of pixels to file "f". */

float frgb_image_undo_gamma (int pixel, nat_t maxval, float gamma);
  /*
    Converts from integer pixel [0..maxval] to float intensity [0..1], 
    taking into account the gamma correction:  
    intensity = (pixel/maxval)^gamma. */

int frgb_image_apply_gamma (float intensity, nat_t maxval, float gamma);
  /*
    Converts from float intensity [0..1] to integer pixel [0..maxval], 
    taking into account the gamma correction:  
    intensity = (pixel/maxval)^gamma. */

#endif