notcurses_menu(3)

NAME

notcurses_menu - operations on ncmenu objects

SYNOPSIS

#include <notcurses/notcurses.h>

    struct ncmenu;
    struct ncplane;
    struct notcurses;
    struct ncmenu_section {
      const char* name;   // utf-8 c string
      struct ncmenu_item {
        const 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 unrolled
    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
      uint64_t 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);

int ncmenu_item_set_status(struct ncmenu* n, const char* section, const char* item, bool enabled);

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

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

struct ncplane* ncmenu_plane(struct ncmenu* n);

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

void ncmenu_destroy(struct ncmenu* n);

DESCRIPTION

A notcurses instance supports menu bars on the top or bottom row of a plane. 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, or no valid item is selected. ncmenu_mouse_selected returns the item selected by a mouse click (described in click), which must be on the actively unrolled section. In either case, if there is a shortcut for the item and ni is not NULL, ni will be filled in with the shortcut.

The menu can be driven either entirely by the application, via direct calls to ncmenu_previtem, ncmenu_prevsection, and the like, or ncinput objects can be handed to ncmenu_offer_input. In the latter case, the menu will largely manage itself. The application must handle item selection (usually via the Enter key and/or mouse click) itself, since the menu cannot arbitrarily call into the application. ncmenu_offer_input will handle clicks to unroll menu sections, clicks to dismiss the menu, Escape to dismiss the menu, left and right to change menu sections, and up and down to change menu items (these latter are only consumed if there is an actively unrolled section).

Items can be disabled with ncmenu_item_set_status. Pass false to disable the item, or true to enable it. All items are enabled by default. A disabled item will not be returned with ncmenu_mouse_selected, nor reached with ncmenu_nextsection nor ncmenu_prevsection.

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 ncinput should be considered irrelevant to the menu.

SEE ALSO

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

AUTHORS
nick black <nickblack@linux.com>.