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

% notcurses_plane(3) % nick black nickblack@linux.com % v1.4.4.1

NAME

notcurses_plane - operations on ncplanes

SYNOPSIS

#include <notcurses/notcurses.h>

struct ncplane ncplane_new(struct notcurses nc, int rows, int cols, int yoff, int xoff, void* opaque);**

struct ncplane ncplane_bound(struct ncplane n, int rows, int cols, int yoff, int xoff, void* opaque);**

struct ncplane ncplane_reparent(struct ncplane n, struct ncplane* newparent);**

struct ncplane ncplane_aligned(struct ncplane n, int rows, int cols, int yoff, ncalign_e align, void* opaque);**

struct ncplane ncplane_dup(struct ncplane n, void* opaque);**

int ncplane_resize(struct ncplane n, int keepy, int keepx, int keepleny, int keeplenx, int yoff, int xoff, int ylen, int xlen);*

int ncplane_move_yx(struct ncplane n, int y, int x);*

void ncplane_yx(const struct ncplane n, int restrict y, int* restrict x);**

int ncplane_set_base_cell(struct ncplane ncp, const cell c);**

int ncplane_set_base(struct ncplane ncp, const char egc, uint32_t attrword, uint64_t channels);**

int ncplane_base(struct ncplane ncp, cell c);**

int ncplane_move_top(struct ncplane n);*

int ncplane_move_bottom(struct ncplane n);*

int ncplane_move_above(struct ncplane restrict n, struct ncplane restrict above);**

int ncplane_move_below(struct ncplane restrict n, struct ncplane restrict below);**

struct ncplane ncplane_below(struct ncplane n);**

char ncplane_at_cursor(struct ncplane n, uint32_t* attrword, uint64_t* channels);**

int ncplane_at_cursor_cell(struct ncplane n, cell c);**

char ncplane_at_yx(const struct ncplane n, int y, int x, uint32_t* attrword, uint64_t* channels);**

int ncplane_at_yx_cell(struct ncplane n, int y, int x, cell c);**

uint32_t ncplane_rgba(const struct ncplane nc, int begy, int begx, int leny, int lenx);**

char ncplane_contents(const struct ncplane nc, int begy, int begx, int leny, int lenx);**

void ncplane_set_userptr(struct ncplane n, void* opaque);**

void ncplane_userptr(struct ncplane n);**

void ncplane_dim_yx(const struct ncplane n, int restrict rows, int* restrict cols);**

static inline int ncplane_dim_y(const struct ncplane n);*

static inline int ncplane_dim_x(const struct ncplane n);*

void ncplane_cursor_yx(const struct ncplane n, int restrict y, int* restrict x);**

void ncplane_translate(const struct ncplane src, const struct ncplane dst, int* restrict y, int* restrict x);**

bool ncplane_translate_abs(const struct ncplane n, int restrict y, int* restrict x);**

uint64_t ncplane_channels(const struct ncplane n);*

uint32_t ncplane_attr(const struct ncplane n);*

void ncplane_set_channels(struct ncplane nc, uint64_t channels);*

void ncplane_set_attr(struct ncplane nc, uint32_t attrword);*

static inline unsigned ncplane_bchannel(struct ncplane nc);*

static inline unsigned ncplane_fchannel(struct ncplane nc);*

static inline unsigned ncplane_fg(struct ncplane nc);*

static inline unsigned ncplane_bg(struct ncplane nc);*

static inline unsigned ncplane_fg_alpha(struct ncplane nc);*

static inline unsigned ncplane_bg_alpha(struct ncplane nc);*

static inline unsigned ncplane_fg_rgb(struct ncplane n, unsigned r, unsigned* g, unsigned* b);**

static inline unsigned ncplane_bg_rgb(struct ncplane n, unsigned r, unsigned* g, unsigned* b);**

int ncplane_set_fg_rgb(struct ncplane n, int r, int g, int b);*

int ncplane_set_bg_rgb(struct ncplane n, int r, int g, int b);*

void ncplane_set_fg_rgb_clipped(struct ncplane n, int r, int g, int b);*

void ncplane_set_bg_rgb_clipped(struct ncplane n, int r, int g, int b);*

int ncplane_set_fg(struct ncplane n, unsigned channel);*

int ncplane_set_bg(struct ncplane n, unsigned channel);*

void ncplane_set_fg_default(struct ncplane n);*

void ncplane_set_bg_default(struct ncplane n);*

int ncplane_set_fg_alpha(struct ncplane n, int alpha);*

int ncplane_set_bg_alpha(struct ncplane n, int alpha);*

int ncplane_set_fg_palindex(struct ncplane n, int idx);*

int ncplane_set_bg_palindex(struct ncplane n, int idx);*

void ncplane_styles_set(struct ncplane n, unsigned stylebits);*

void ncplane_styles_on(struct ncplane n, unsigned stylebits);*

void ncplane_styles_off(struct ncplane n, unsigned stylebits);*

unsigned ncplane_styles(const struct ncplane n);*

void ncplane_greyscale(struct ncplane n);*

int ncplane_blit_bgrx(struct ncplane nc, int placey, int placex, int linesize, ncblitter_e blitter, const unsigned char data, int begy, int begx, int leny, int lenx);**

int ncplane_blit_rgba(struct ncplane nc, int placey, int placex, int linesize, ncblitter_e blitter, const unsigned char data, int begy, int begx, int leny, int lenx);**

int ncplane_destroy(struct ncplane ncp);*

void notcurses_drop_planes(struct notcurses nc);*

int ncplane_mergedown(struct ncplane restrict src, struct ncplane restrict dst);**

void ncplane_erase(struct ncplane n);*

bool ncplane_set_scrolling(struct ncplane n, bool scrollp);*

int ncplane_rotate_cw(struct ncplane n);*

int ncplane_rotate_ccw(struct ncplane n);*

DESCRIPTION

Ncplanes are the fundamental drawing object of notcurses. All output functions take a struct ncplane as an argument. They can be any size, and placed anywhere. In addition to its framebuffer--a rectilinear matrix of cells (see notcurses_cell(3))--an ncplane is defined by:

• a base cell, used for any cell on the plane without a glyph,
• the egcpool backing its cells,
• a current cursor location,
• a current style, foreground channel, and background channel,
• its geometry,
• a configured user pointer,
• its position relative to the visible plane, and
• its z-index.

New planes can be created with ncplane_new, ncplane_bound, and ncplane_aligned. If a plane is bound to another, x and y coordinates are relative to the plane to which it is bound, and if that plane moves, all its bound planes move along with it. When a plane is destroyed, all planes bound to it (directly or transitively) are destroyed. ncplane_reparent detaches the plane n from any plane to which it is bound, and binds it to newparent if newparent is not NULL. All planes bound to n move along with it during a reparenting operation.

ncplane_destroy destroys a particular ncplane, after which it must not be used again. notcurses_drop_planes destroys all ncplanes other than the stdplane. Any references to such planes are, of course, invalidated. It is undefined to destroy a plane concurrently with any other operation involving that plane, or any operation involving the z-axis.

It is an error for two threads to concurrently mutate a single ncplane. So long as rendering is not taking place, however, multiple threads may safely output to multiple ncplanes. So long as all threads are readers, multiple threads may work with a single ncplane. A reading function is any which accepts a const struct ncplane.

ncplane_translate translates coordinates expressed relative to the plane src, and writes the coordinates of that cell relative to dst. The cell need not intersect with dst, though this will yield coordinates which are invalid for writing or reading on dst. If dst is NULL, it is taken to refer to the standard plane. ncplane_translate_abs takes coordinates expressed relative to the standard plane, and returns coordinates relative to dst, returning false if the coordinates are invalid for dst.

ncplane_mergedown writes to dst the frame that would be rendered if only src and dst existed on the z-axis, ad dst represented the entirety of the rendering region. Only those cells where src intersects with dst might see changes. It is an error to merge a plane onto itself.

ncplane_erase zeroes out every cell of the plane, dumps the egcpool, and homes the cursor. The base cell is preserved.

Scrolling

All planes, including the standard plane, are created with scrolling disabled. Control scrolling on a per-plane basis with ncplane_set_scrolling. Attempting to print past the end of a line will stop at the plane boundary, and indicate an error. On a plane 10 columns wide and two rows high, printing "0123456789" at the origin should succeed, but printing "01234567890" will by default fail at the eleventh character. In either case, the cursor will be left at location 0x10; it must be moved before further printing can take place. If scrolling is enabled, the first row will be filled with 01234546789, the second row will have 0 written to its first column, and the cursor will end up at 1x1. Note that it is still an error to manually attempt to move the cursor off-plane, or to specify off-plane output. Boxes do not scroll; attempting to draw a 2x11 box on our 2x10 plane will result in an error and no output. When scrolling is enabled, and output takes place while the cursor is past the end of the last row, the first row is discarded, all other rows are moved up, the last row is cleared, and output begins at the beginning of the last row. This does not take place until output is generated (i.e. it is possible to fill a plane when scrolling is enabled).

RETURN VALUES

ncplane_new, ncplane_bound, ncplane_aligned, and ncplane_dup all return a new struct ncplane on success, or NULL on failure.

ncplane_userptr returns the configured user pointer for the ncplane, and cannot fail.

ncplane_below returns the plane below the specified ncplane. If the provided plane is the bottommost plane, NULL is returned. It cannot fail.

ncplane_set_scrolling returns true if scrolling was previously enabled, and false otherwise.

ncplane_at_yx and ncplane_at_cursor return a heap-allocated copy of the EGC at the relevant cell, or NULL if the cell is invalid. The caller should free this result. ncplane_at_yx_cell and ncplane_at_cursor_cell instead load these values into a cell, which is invalidated if the associated plane is destroyed. The caller should release this cell with cell_release.

Functions returning int return 0 on success, and non-zero on error.

All other functions cannot fail (and return void).

NOTES

SEE ALSO

notcurses(3), notcurses_cell(3), notcurses_output(3), notcurses_stdplane(3)