NAME¶

notcurses_plane - operations on ncplanes

SYNOPSIS¶

#include <notcurses/notcurses.h>

#define NCPLANE_OPTION_HORALIGNED   0x0001ull
#define NCPLANE_OPTION_VERALIGNED   0x0002ull
#define NCPLANE_OPTION_MARGINALIZED 0x0004ull
#define NCPLANE_OPTION_FIXED        0x0008ull
typedef struct ncplane_options {


  int y;            // vertical placement relative to parent plane


  int x;            // horizontal placement relative to parent plane


  int rows;         // number of rows, must be positive


  int cols;         // number of columns, must be positive


  void* userptr;    // user curry, may be NULL


  const char* name; // name (used only for debugging), may be NULL


  int (*resizecb)(struct ncplane*); // called on parent resize


  uint64_t flags;   // closure over NCPLANE_OPTION_*


  unsigned margin_b, margin_r; // bottom and right margins
} ncplane_options;
#define NCSTYLE_MASK      0xffffu
#define NCSTYLE_ITALIC    0x0010u
#define NCSTYLE_UNDERLINE 0x0008u
#define NCSTYLE_UNDERCURL 0x0004u
#define NCSTYLE_BOLD      0x0002u
#define NCSTYLE_STRUCK    0x0001u
#define NCSTYLE_NONE      0
    

struct ncplane* ncplane_create(struct ncplane* n, const ncplane_options* nopts);

struct ncplane* ncpile_create(struct notcurses* n, const ncplane_options* nopts);

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

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

int ncplane_descendant_p(const struct ncplane* n, const struct ncplane* ancestor);

int ncplane_resize_realign(struct ncplane* n);

int ncplane_resize_maximize(struct ncplane* n);

int ncplane_resize_marginalized(struct ncplane* n);

int ncplane_resize_placewithin(struct ncplane* n);

void ncplane_set_resizecb(struct ncplane* n, int(resizecb)(struct ncplane));

int (ncplane_resizecb(const struct ncplane n**))(struct ncplane*);**

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);

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

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

int ncplane_y(const struct ncplane* n);

int ncplane_x(const struct ncplane* n);

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

int ncplane_abs_y(const struct ncplane* n);

int ncplane_abs_x(const struct ncplane* n);

struct ncplane* ncplane_parent(struct ncplane* n);

const struct ncplane* ncplane_parent_const(const struct ncplane* n);

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

int ncplane_set_base(struct ncplane* ncp, const char* egc, uint16_t stylemask, uint64_t channels);

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

static inline void ncplane_move_top(struct ncplane* n);

static inline void ncplane_move_bottom(struct ncplane* n);

void ncplane_move_family_top(struct ncplane* n);

void ncplane_move_family_bottom(struct ncplane* n);

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

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

int ncplane_move_family_above(struct ncplane* restrict n, struct ncplane* restrict targ);

int ncplane_move_family_below(struct ncplane* restrict n, struct ncplane* restrict targ);

struct ncplane* ncplane_below(struct ncplane* n);

struct ncplane* ncplane_above(struct ncplane* n);

char* ncplane_at_cursor(struct ncplane* n, uint16_t* stylemask, uint64_t* channels);

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

char* ncplane_at_yx(const struct ncplane* n, int y, int x, uint16_t* stylemask, uint64_t* channels);

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

uint32_t* ncplane_as_rgba(const struct ncplane* nc, ncblitter_e blit, unsigned begy, unsigned begx, unsigned leny, unsigned lenx, unsigned* pxdimy, unsigned* pxdimx);

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

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

void* ncplane_userptr(struct ncplane* n);

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

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

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

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

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

static inline unsigned ncplane_bchannel(struct ncplane* nc);

static inline unsigned ncplane_fchannel(struct ncplane* nc);

static inline unsigned ncplane_fg_rgb8(struct ncplane* nc);

static inline unsigned ncplane_bg_rgb8(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_rgb8(struct ncplane* n, unsigned* r, unsigned* g, unsigned* b);

static inline unsigned ncplane_bg_rgb8(struct ncplane* n, unsigned* r, unsigned* g, unsigned* b);

int ncplane_set_fg_rgb8(struct ncplane* n, unsigned r, unsigned g, unsigned b);

int ncplane_set_bg_rgb8(struct ncplane* n, unsigned r, unsigned g, unsigned b);

void ncplane_set_fg_rgb8_clipped(struct ncplane* n, int r, int g, int b);

void ncplane_set_bg_rgb8_clipped(struct ncplane* n, int r, int g, int b);

int ncplane_set_fg_rgb8(struct ncplane* n, uint32_t channel);

int ncplane_set_bg_rgb8(struct ncplane* n, uint32_t 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, unsigned alpha);

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

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

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

uint16_t ncplane_styles(const struct ncplane* n);

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

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

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

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* src, struct ncplane* dst, int begsrcy, int begsrcx, unsigned leny, unsigned lenx, int dsty, int dstx);

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

void ncplane_erase(struct ncplane* n);

int ncplane_erase_region(struct ncplane* n, int ystart, int xstart, int ylen, int xlen);

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

bool ncplane_scrolling_p(const struct ncplane* n);

int ncplane_scrollup(struct ncplane* n, int r);

int ncplane_scrollup_child(struct ncplane* n, const struct ncplane* child);

int ncplane_rotate_cw(struct ncplane* n);

int ncplane_rotate_ccw(struct ncplane* n);

void ncplane_pixel_geom(const struct notcurses* n, unsigned* restrict pxy, unsigned* restrict pxx, unsigned* restrict celldimy, unsigned* restrict celldimx, unsigned* restrict maxbmapy, unsigned* restrict maxbmapx);

int ncplane_set_name(struct ncplane* n, const char* name);

char* ncplane_name(const 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 nccells (see notcurses_cell(3))--an ncplane is defined by:

•

a base nccell, used for any cell on the plane without a glyph,

•

the egcpool backing its nccells,

•

a current cursor location,

•

a current style, foreground channel, and background channel,

•

its geometry,

•

a configured user pointer,

•

position relative to the standard plane,

•

the plane, if any, to which it is bound,

•

the next plane bound by the plane to which it is bound,

•

the head of the list of its bound planes,

•

its resize methodology,

•

whether a sprixel (see notcurses_visual(3)) is associated,

•

its z-index, and

•

a name (used only for debugging).

New planes can be created with ncplane_create. If a plane is bound to another, x and y coordinates are relative to the plane to which it is bound, and if this latter 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.

If the NCPLANE_OPTION_HORALIGNED flag is provided, x is interpreted as an ncalign_e rather than an absolute position. If the NCPLANE_OPTION_VERALIGNED flag is provided, y is interpreted as an ncalign_e rather than an absolute postiion. Either way, all positions are relative to the parent plane. ncplane_resize_realign should usually be used together with these flags, so that the plane is automatically realigned upon a resize of its parent.

If the NCPLANE_OPTION_MARGINALIZED flag is provided, neither NCPLANE_OPTION_HORALIGNED nor NCPLANE_OPTION_VERALIGNED may be provided, and rows and cols must both be 0. y and x will be interpreted as top and left margins. margin_b and margin_r will be interpreted as bottom and right margins. The plane will take the maximum space possible subject to its parent planes and these margins. The plane cannot become smaller than 1x1 (the margins are best-effort). ncplane_resize_marginalized should usually be used together with this flag, so that the plane is automatically resized.

ncplane_reparent detaches the plane n from any plane to which it is bound, and binds it to newparent. Its children are reparented to its previous parent. The standard plane cannot be reparented. If newparent is NULL, the plane becomes the root plane of a new, unrendered stack. When ncplane_reparent_family is used, all planes bound to n move along with it during a reparenting operation. See Piles below.

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.

A plane can be moved relative to its parent plane's origin with ncplane_move_yx. If the plane has no parent, the move is relative to the rendering area. A plane can be moved off-screen entirely, in which case it will not be visible following rasterization; it can also be partially off-screen.

A plane has a virtual cursor; Set its new position with ncplane_cursor_move_yx. Specifying -1 as one or both coordinates will hold that axis constant. You may move a cursor relatively to its current position with ncplane_cursor_move_rel. Unless coordinates are specified for a call, action takes place at the plane's virtual cursor, which automatically moves along with output. The current virtual cursor location can be acquired with ncplane_cursor_yx.

ncplane_yx returns the coordinates of the specified plane's origin, relative to the plane to which it is bound. Either or both of y and x may be NULL. ncplane_y and ncplane_x allow a single component of this location to be retrieved. ncplane_abs_yx returns the coordinates of the specified plane's origin relative to its pile.

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, as are the active attributes. ncplane_erase_region does the same for a subregion of the plane. For the latter, supply 0 for ylen and/or xlen to erase through that dimension, starting at the specified point. Supply -1 for ystart and/or xstart to use the cursor's current position along that axis for a starting point. Negative ylen and xlen move up and to the left from the starting coordinate; positive ylen and xlen move down and to the right from same. See BUGS below.

When a plane is resized (whether by ncplane_resize, SIGWINCH, or any other mechanism), a depth-first recursion is performed on its children. Each child plane having a non-NULL resizecb will see that callback invoked following resizing of its parent's plane. If it returns non-zero, the resizing cascade terminates, returning non-zero. Otherwise, resizing proceeds recursively.

ncplane_move_top and ncplane_move_bottom extract their argument n from the z-axis, and reinsert it at the top or bottom, respectively, of its pile. These functions are both O(1). ncplane_move_family_top and ncplane_move_family_bottom do the same, and move any bound descendants along with the plane. Ordering among the plane and its descendants will be maintained. For example, assume a pile with A at the top of its z-axis, followed by B, C, D, and E, where E is bound to C. Calling ncplane_move_family_top on C will result in the order CEABD. Calling ncplane_move_family_bottom on C will result in the order ABDCE. Calling ncplane_move_family_top or ncplane_move_top on E will result in EABCD. Calling ncplane_move_family_bottom on E is a no-op. These two functions are O(N) on the number of planes in the pile.

ncplane_move_above and ncplane_move_below move the argument n above or below, respectively, the argument targ. Both operate in O(1).

RETURN VALUES¶

ncplane_create and ncplane_dup 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 an nccell, which is invalidated if the associated plane is destroyed. The caller should release this nccell with nccell_release.

ncplane_as_rgba returns a heap-allocated array of uint32_t values, each representing a single RGBA pixel, or NULL on failure.

ncplane_erase_region returns -1 if ystart or xstart are less than -1, or outside the plane.

ncplane_cursor_move_yx returns -1 if the coordinates are beyond the dimensions of the specified plane (except for the special value -1).

ncplane_cursor_move_rel returns -1 if the coordinates are beyond the dimensions of the specified plane.

ncplane_name returns a heap-allocated copy of the plane's name, or NULL if it has no name (or on error).

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

All other functions cannot fail (and return void).

NOTES¶

BUGS¶

ncplane_at_yx doesn't yet account for bitmap-based graphics (see notcurses_visual(3)). Whatever glyph-based contents existed on the plane when the bitmap was blitted will continue to be returned.

When the alternate screen is not used (see notcurses_init(3)), the contents of the terminal at startup remain present until obliterated on a cell-by-cell basis. ncplane_erase and ncplane_erase_region cannot be used to clear the terminal of startup content. If you want the screen cleared on startup, but do not want to use (or rely on) the alternate screen, use something like:

ncplane_set_base(notcurses_stdplane(nc), " ", 0, 0);
notcurses_render(nc);
    

or simply:

notcurses_refresh(nc);
    

SEE ALSO¶

notcurses(3), notcurses_capabilities(3), notcurses_cell(3), notcurses_output(3), notcurses_pile(3), notcurses_stdplane(3), notcurses_visual(3)

AUTHORS¶

nick black <nickblack@linux.com>.