/* ppmoquant.h - options, types and prototypes for ppmoquant.c */
/* Last edited on 2006-11-22 13:41:38 by stolfi */

#include <jspnm.h>
#include <jspnm_image.h>
#include <jsppmcmap.h>

#define MAXCOLORS 32767

/* COMMAND-LINE OPTIONS */

typedef int (*matchfn)(
    long br, long bg, long bb, 
    long wr, long wg, long wb, 
    int maxval,
    ppm_cmapx_hist_vector cm, 
    int ncolors,
    int mapmaxval
  );
  /* A function that finds the best (opaque) match to the color
    interval [r1_r2]x[g1_g2]x[b1_b2] in the colormap cm. Note that 
    the interval may be somewhat outside the color cube. */

typedef struct options_t
  { bool_t floyd; 
    matchfn match;
    rgb_pixel_t transp;
    int transpmaxval;
    char *cmapname;
    char *bimgname; 
    char *wimgname;
  } options_t;

/* Prototypes */

int main(int argc, char* argv[]);

options_t *parse_options(int argc, char **argv);

rgb_pixel_t my_parsecolor(char *colorspec, int *maxvalp);
  /* Parses a colorspec, returns the pixel value and stores its 
    respective maxval in (*maxvalp).
    
    Syntax is the same as in ppm_parsecolor, but
    also accepts an RGB pixel in the format "(R,G,B)".  These are
    decimal coordinates, relative to the colormap's maxval.  The
    parameter (*maxvalp) is set to zero to denote this fact.
    
    All other formats are relative to some format-dependent
    maxval, which gets assigned to (*maxvalp). */

static rgb_pixel_t
adjust_transp_color(rgb_pixel_t p, int oldmaxval, int newmaxval);
  /* Rescales the pixel p from [0..oldmaxval] to [0..newmaxval],
    unless oldmaxval = 0 (when p itself is returned). */
  
static rgb_pixel_t* 
find_color(
    rgb_pixel_t p,
    ppm_cmapx_hist_vector cm, 
    int ncolors
  );
  /* Looks for an exact match to p in cm[0..ncolors-1].
    Returns pointer to pixel if found, NULL if not found. */

static ppm_cmapx_hist_vector
collect_colors(pnm_image_t *map, int *ncolorsp);
  /* Turn map->pixels into a colormap. */

static void
floyd_quantize_ppm_images(
    pnm_image_t *bimg, 
    pnm_image_t *wimg, 
    ppm_cmapx_hist_vector cm, 
    int ncolors,
    rgb_pixel_t transp,
    int mapmaxval,
    matchfn match
  );
  /* Replaces each pixel in bimg by a pixel from the given colormap,
    or the "transp" (transparent) pixel, by comparing the two colors. */

typedef struct {
    long* thisr;
    long* nextr;
    long* thisg;
    long* nextg;
    long* thisb;
    long* nextb;
  } fs_errors;

static void
floyd_alloc_error_vectors(fs_errors *ep, int cols);

static void
floyd_propagate_error_opaque(
    long br, long bg, long bb,
    long wr, long wg, long wb,
    rgb_pixel_t *newp, float coef,
    fs_errors *bep, fs_errors *wep,
    int col,
    int fs_direction
  );
  /* Propagates Floyd-Steinberg error terms for opaque pixel choice.
    The old pixels are br, bg, bb, wr, wg, wb.
    The new pixel is (*newp).  
    Assumes coef = FS_SCALE*(oldmaxval/newmaxval). */
  
static void 
floyd_propagate_error_transp(
    long br, long bg, long bb,
    long wr, long wg, long wb,
    int maxval,
    fs_errors *bep, fs_errors *wep,
    int col,
    int fs_direction
  );
  /* Propagates Floyd-Steinberg error terms for transparent pixel choice.
    The old pixels are br, bg, bb, wr, wg, wb. */
  
static void
floyd_swap_error_vectors(fs_errors *ep);

static void
plain_quantize_ppm_images(
    pnm_image_t *bimg, 
    pnm_image_t *wimg, 
    ppm_cmapx_hist_vector cm, 
    int ncolors,
    rgb_pixel_t transp,
    int mapmaxval,
    matchfn match
  );

static rgb_pixel_t*
choose_color (
    long r0, long g0, long b0,
    long r1, long g1, long b1,
    int maxval,
    ppm_cmapx_hist_vector cm, 
    int ncolors,
    int mapmaxval,
    matchfn match
  );
  /* Finds best match to the color interval (r0,g0,b0)--(r1,g1,b1) 
    in colormap cm plus the "transparent" color.  Returns NULL
    if the best match is "transparent". */
  
static int
rgb_match_range (
    long br, long bg, long bb,
    long wr, long wg, long wb,
    int maxval,
    ppm_cmapx_hist_vector cm, 
    int ncolors,
    int mapmaxval
  );
  /* Search colormap for closest match to given color range. */