notcurses/doc/man/man3/notcurses_channels.3.md

% notcurses_channels(3) % nick black nickblack@linux.com % v2.4.99

NAME

notcurses_channels - operations on notcurses channels

SYNOPSIS

#include <notcurses/notcurses.h>

#define NCCHANNEL_INITIALIZER(r, g, b) \
  (((uint32_t)r << 16u) + ((uint32_t)g << 8u) + (b) + NC_BGDEFAULT_MASK)

#define NCCHANNELS_INITIALIZER(fr, fg, fb, br, bg, bb) \
  ((NCCHANNEL_INITIALIZER(fr, fg, fb) << 32ull) + \
   (NCCHANNEL_INITIALIZER(br, bg, bb)))

uint32_t ncchannel_r(uint32_t channel);

uint32_t ncchannel_g(uint32_t channel);

uint32_t ncchannel_b(uint32_t channel);

uint32_t ncchannel_rgb8(uint32_t channel, uint32_t restrict r, uint32_t restrict g, uint32_t* restrict b);**

int ncchannel_set_rgb8(uint32_t channel, unsigned r, unsigned g, unsigned b);*

int ncchannel_set(uint32_t channel, uint32_t rgb);*

uint32_t ncchannel_alpha(uint32_t channel);

int ncchannel_set_alpha(uint32_t channel, unsigned alpha);*

bool ncchannel_default_p(uint32_t channel);

uint32_t ncchannel_set_default(uint32_t channel);*

uint32_t ncchannels_fg_rgb(uint64_t channels);

uint32_t ncchannels_bg_rgb(uint64_t channels);

int ncchannels_set_fg_rgb(uint64_t channels, uint32_t rgb);*

int ncchannels_set_bg_rgb(uint64_t channels, uint32_t rgb);*

unsigned ncchannels_fg_alpha(uint64_t channels);

unsigned ncchannels_bg_alpha(uint64_t channels);

int ncchannels_set_fg_alpha(uint64_t channels, int alpha);*

int ncchannels_set_bg_alpha(uint64_t channels, int alpha);*

uint32_t ncchannels_fg_rgb8(uint64_t channels, unsigned r, unsigned g, unsigned* b);**

uint32_t ncchannels_bg_rgb8(uint64_t channels, unsigned r, unsigned g, unsigned* b);**

int ncchannels_set_fg_rgb8(uint64_t channels, unsigned r, unsigned g, unsigned b);*

int ncchannels_set_bg_rgb8(uint64_t channels, unsigned r, unsigned g, unsigned b);*

bool ncchannels_fg_default_p(uint64_t channels);

bool ncchannels_bg_default_p(uint64_t channels);

uint64_t ncchannels_set_fg_default(uint64_t channels);*

uint64_t ncchannels_set_bg_default(uint64_t channels);*

uint64_t ncchannels_reverse(uint64_t channels);

unsigned ncchannel_palindex(uint32_t channel);

bool ncchannel_palindex_p(uint32_t channel);

int ncchannel_set_palindex(uint32_t channel, int idx);*

unsigned ncchannels_fg_palindex(uint64_t channels);

unsigned ncchannels_bg_palindex(uint64_t channels);

int ncchannels_set_fg_palindex(uint64_t channels, int idx);*

int ncchannels_set_bg_palindex(uint64_t channels, int idx);*

uint64_t ncchannels_combine(uint32_t fchan, uint32_t bchan);

DESCRIPTION

ncchannel_palindex extracts the palette index from a channel. The channel must be palette-indexed, or the return value is meaningless. Verify palette indexing with ncchannel_palindex_p. A channel can be set to palette indexed mode (and have the index set) with ncchannel_set_palindex. The index must be less than NCPALETTESIZE.

ncchannels_combine creates a new channel pair using fchan as the foreground channel and bchan as the background channel.

RETURN VALUES

Functions returning int return -1 on failure, or 0 on success. Failure is always due to invalid inputs. Functions returning bool are predicates, and return the requested value. Functions returning unsigned forms return the input, modified as requested.

ncchannels_reverse inverts the color components of the two channels, while holding all other elements constant. It's the Notcurses approximation to reverse video.

SEE ALSO

notcurses(3), notcurses_cell(3), notcurses_plane(3), notcurses_output(3)