#ifndef PACKED_PIXMAP_H_INCLUDED
#define PACKED_PIXMAP_H_INCLUDED

#include <stdint.h>

#include "pixmap.h"

/* A pixmap backed by a packed bit map in memory.
 *
 * A packed bit map is a packed array of bytes (uint8_t) in which each
 * pixel of the image corresponds to a single bit of memory.
 *
 * The pixels are laid out as follows: each line corresponds to a
 * packed sequence of bytes.  Let L be a pointer to the first byte
 * representing a line, then the pixel in position x=0 on that line is
 * the least significant bit in the first byte L[0], the pixel in
 * position x=7 corresponds to the most significant in L[0], the pixel
 * in position x=8 then corresponds to the least significant bit in
 * L[1], and so on.
 *
 * If the width of the packed_pixmap image is not a multiple of 8, then some
 * of the bits in the last byte of each line will be ignored.
 *
 * Lines are packed one after the other, with the first line
 * corresponding to the y=0 coordinate.
 *
 * HINT: you can set a bit in position i (i < 8) to 1 in a uint8_t
 * object x with the following code: 
 *
 * uint8_t mask = 1; mask <<= i; x |= mask;
 *
 * or you can set it to 0 with the following code: 
 * 
 * uint8_t mask = 1; mask <<= i; x &= ~mask;
 */

struct packed_pixmap;

/* Create a new packed pixmap backed by the given memory buffer.
 *
 * w is the number of characters in each line; h is the number of
 * lines; mem is a pointer to a memory region used to store the
 * pixels.  This region is passed and owned by the user.  It is also
 * assumed to be large enough to hold the packed pixel map.
 */
extern struct pixmap * packed_pixmap_new(unsigned int w, unsigned int h, uint8_t * mem);

#endif