sixel.h

#ifndef SIXEL_H
#define SIXEL_H

#define DECSIXEL_PARAMS_MAX 16
#define DECSIXEL_PALETTE_MAX 1024
#define DECSIXEL_PARAMVALUE_MAX 65535
#define DECSIXEL_WIDTH_MAX 4096
#define DECSIXEL_HEIGHT_MAX 4096

typedef unsigned short sixel_color_no_t;
typedef unsigned int sixel_color_t;

typedef struct sixel_image_buffer {
	sixel_color_no_t *data;
	int width;
	int height;
	sixel_color_t palette[DECSIXEL_PALETTE_MAX];
	sixel_color_no_t ncolors;
	int palette_modified;
	int use_private_register;
} sixel_image_t;

typedef enum parse_state {
	PS_ESC        = 1,  /* ESC */
	PS_DECSIXEL   = 2,  /* DECSIXEL body part ", $, -, ? ... ~ */
	PS_DECGRA     = 3,  /* DECGRA Set Raster Attributes " Pan; Pad; Ph; Pv */
	PS_DECGRI     = 4,  /* DECGRI Graphics Repeat Introducer ! Pn Ch */
	PS_DECGCI     = 5,  /* DECGCI Graphics Color Introducer # Pc; Pu; Px; Py; Pz */
} parse_state_t;

typedef struct parser_context {
	parse_state_t state;
	int pos_x;
	int pos_y;
	int max_x;
	int max_y;
	int attributed_pan;
	int attributed_pad;
	int attributed_ph;
	int attributed_pv;
	int repeat_count;
	int color_index;
	int bgindex;
	int grid_width;
	int grid_height;
	int param;
	int nparams;
	int params[DECSIXEL_PARAMS_MAX];
	sixel_image_t image;
} sixel_state_t;

int sixel_parser_init(sixel_state_t *st, sixel_color_t fgcolor, sixel_color_t bgcolor, unsigned char use_private_register, int cell_width, int cell_height);
int sixel_parser_parse(sixel_state_t *st, unsigned char *p, size_t len);
int sixel_parser_set_default_color(sixel_state_t *st);
int sixel_parser_finalize(sixel_state_t *st, unsigned char *pixels);
void sixel_parser_deinit(sixel_state_t *st);

#endif