/* ppmcmap.h - header file for colormap routines in libppm
*/

/* Color histogram stuff. */

typedef struct colorhist_item* colorhist_vector;
struct colorhist_item
    {
    pixel color;
    int value;
    };

typedef struct colorhist_list_item* colorhist_list;
struct colorhist_list_item
    {
    struct colorhist_item ch;
    colorhist_list next;
    };

colorhist_vector ppm_computecolorhist( pixel** pixels, int cols, int rows, int maxcolors, int* colorsP );
/* Returns a colorhist *colorsP long (with space allocated for maxcolors). */

colorhist_vector ppm_graycolorhist( int numcolors );
/* Returns a colorhist hardcoded with the grayscale values from
** 0 to numcolors-1.
*/

void ppm_addtocolorhist( colorhist_vector chv, int* colorsP, int maxcolors, pixel* colorP, int value, int position );

void ppm_freecolorhist( colorhist_vector chv );


/* Color hash table stuff. */

typedef colorhist_list* colorhash_table;

colorhash_table ppm_computecolorhash( pixel** pixels, int cols, int rows, int maxcolors, int* colorsP );

int
ppm_lookupcolor( colorhash_table cht, pixel* colorP );

colorhist_vector ppm_colorhashtocolorhist( colorhash_table cht, int maxcolors );
colorhash_table ppm_colorhisttocolorhash( colorhist_vector chv, int colors );

int ppm_addtocolorhash( colorhash_table cht, pixel* colorP, int value );
/* Returns -1 on failure. */

colorhash_table ppm_alloccolorhash( void );

void ppm_freecolorhash( colorhash_table cht );