notcurses_menu(3)

nick black

v1.6.1

NAME

notcurses_menu - operations on menus

SYNOPSIS

#include <notcurses/notcurses.h>

struct ncmenu;
struct ncplane;
struct ncinput;
struct notcurses;

struct ncmenu_section {
  char* name;  // utf-8 c string
  struct ncmenu_item {
    char* desc;  // utf-8 menu item, NULL for horizontal separator
    ncinput shortcut;  // shortcut, all should be distinct
  }* items;
  int itemcount;
};

#define NCMENU_OPTION_BOTTOM 0x0001 // bottom row (as opposed to top row)
#define NCMENU_OPTION_HIDING 0x0002 // hide the menu when not being used

typedef struct ncmenu_options {
  struct ncmenu_section* sections; // 'sectioncount' menu_sections
  int sectioncount;         // must be positive
  uint64_t headerchannels;  // styling for header
  uint64_t sectionchannels; // styling for sections
  unsigned flags;           // bitfield on NCMENU_OPTION_*
} ncmenu_options;

struct ncmenu* ncmenu_create(struct notcurses* nc, const menu_options* opts);

int ncmenu_unroll(struct ncmenu* n, int sectionidx);

int ncmenu_rollup(struct ncmenu* n);

int ncmenu_nextsection(struct ncmenu* n);

int ncmenu_prevsection(struct ncmenu* n);

int ncmenu_nextitem(struct ncmenu* n);

int ncmenu_previtem(struct ncmenu* n);

const char* ncmenu_selected(const struct ncmenu* n, struct ncinput* ni);

struct ncplane* ncmenu_plane(struct ncmenu* n);

bool ncmenu_offer_input(struct ncmenu* n, const struct ncinput* nc);

int ncmenu_destroy(struct ncmenu* n);

DESCRIPTION

A notcurses instance supports menu bars on the top or bottom row of the true screen. A menu is composed of sections, which are in turn composed of items. Either no sections are visible, and the menu is rolled up, or exactly one section is unrolled. ncmenu_rollup places an ncmenu in the rolled up state. ncmenu_unroll rolls up any unrolled section, and unrolls the specified one. ncmenu_destroy removes a menu bar, and frees all associated resources.

ncmenu_selected return the selected item description, or NULL if no section is unrolled.

The menu can be driven either entirely by the application, via direct calls to ncmenu_previtem, ncmenu_prevsection, and the like, or struct ncinput objects can be handed to ncmenu_offer_input. In the latter case, the menu will largely manage itself.

RETURN VALUES

ncmenu_create returns NULL on error, or a pointer to a valid new ncmenu. Other functions return non-zero on error, or zero on success. Almost all errors are due to invalid parameters.

ncmenu_offer_input returns true if the menu “consumed” the input, i.e. found it relevant and took an action. Otherwise, false is returned, and the struct ncinput should be considered irrelevant to the menu.

SEE ALSO

notcurses(3), notcurses_input(3), notcurses_plane(3)