3 * A tiled window manager for the terminal.
5 * It provides a virtual screen that can be scrolled horizontally and may
6 * contain any number of windows that can be appeared, disappeared, resized and
7 * (somewhat) moved around. They have borders and a title bar and are positioned
8 * (in a bizarre fashion, see below) automatically.
10 * Windows can be almost any width (number has to fit into 16 bits); the virtual
11 * screen grows with them as needed -- but only horizontally and only up to 2^16
12 * cells. Their height is limited by the height of the terminal screen.
14 * Positioning of windows can only indirectly be influenced: by resizing them,
15 * and by shifting their relative position inside the (currently invisible)
16 * chain that the window manager treats their plurality as. The first window
17 * goes into the upper left corner of the virtual screen. Further visible
18 * windows are fitted left-aligned below their (chain-wise) closest predecessor
19 * that thrones over enough space to fit them in; failing that, they are placed
20 * to the right of the window with the rightmost border.
22 * Functions that return uint8_t return these error codes:
24 * 1 - memory allocation error (of ncurses' pads/windows, or scroll hint texts)
25 * 2 - activity forces virtual screen to grow beyond width of 2^16 cells
27 * TODO: Expose less internals to the API.
29 * TODO: Think up a more intuitive window positioning algorithm or at least make
30 * the chain that windows are positioned by visible.
38 #include <stdint.h> /* for uint8_t, uint16_t, uint32_t */
39 #include <ncurses.h> /* for the WINDOW typedef */
40 #include "yx_uint16.h" /* for yx_uint16 coordinates */
44 /* Individual windows consist of potential (real only if window is visible
45 * inside the virtual screen) ncurses WINDOWs wrapped inside Frame structs (that
46 * keep a window's designated size even when it is invisible) wrapped inside
47 * metadata-rich Win structs. Win structs are chained into a linked list of all
48 * the windows visible on the virtual screen and also contain pointers to what
49 * content is to be drawn inside the window, and by use of what method.
52 struct Frame /* If Frame is Win's "frame", "size" is the */
53 { /* designated size of curses_win's ncurses WINDOW. */
54 WINDOW * curses_win; /* If Frame is WinMeta's "padframe", curses_win is */
55 struct yx_uint16 size; /* the ncurses pad representing the virtual screen */
56 }; /* and "size" desribes the terminal screen size. */
60 /* members supposed to be used ONLY INTERNALLY */
61 struct Win * _prev; /* chain pointers; if 0, they mark the start or end */
62 struct Win * _next; /* of the chain; if both are 0, Win is outside chain */
63 struct yx_uint16 _start; /* upper left corner of "frame" WINDOW */
64 char * _title; /* title to be used in window title bar */
65 void (* _draw) (struct Win *); /* how to draw window content ("data") */
67 /* members to be available EXTERNALLY */
69 void * data; /* window content to be drawn by _draw() */
74 /* The window manager's parent struct WinMeta contains the virtual screen,
75 * relates it to the terminal screen and anchors the chain of visible windows.
79 /* members supposed to be used ONLY INTERNALLY */
80 WINDOW * _screen; /* ncurses' pointer to the terminal screen */
81 struct Win * _chain_start; /* first Win in chain; its _prev == 0 */
82 struct Win * _chain_end; /* last Win in chain; its _next == 0 */
84 /* members to be available EXTERNALLY */
85 uint16_t pad_offset; /* number of cells view is moved to the right */
86 struct Frame padframe; /* virtual screen fitted into terminal screen */
87 struct Win * active; /* Win highlighted/selected for manipulation */
92 /* Initialize empty WinMeta "wmeta" on the terminal "screen". (Note that
93 * emptiness is marked by WinMeta.chain_start=0.) Other struct members are also
94 * initialized 0, except for the virtual screen (height = that of the terminal
95 * screen; width = 1) amd its frame sized to the size of the terminal screen.
97 extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta * wmeta);
101 /* Create a window as child of "wmeta" titled "title" of "height" and "width"
102 * and appointing "func"() to interpret and draw the content stored at "data"
103 * if the window is visible.
105 * A value for "width" <1 will trigger a fallback to width=1. A "height" < 1 or
106 * larger than the maximum window height possible within the virtual screen will
107 * trigger a fallback to the maximum height possible (i.e. pass a "height" of 0
108 * to initialize the window to its largest possible height).
110 * Other members of the Win struct are initialized to 0. The window will stay
111 * invisible until appended to the chain of visible windows via append_win().
113 extern struct Win init_win(struct WinMeta * wmeta, char * title,
114 uint16_t height, uint16_t width,
115 void * data, void * func);
119 /* Append/suspend window "w" to/from chain of visible windows below "wmeta".
120 * Appended windows will become active. Suspended active windows will move the
121 * active window selection to their successor in the window chain or, failing
122 * that, their predecessor; if no window remains, none will be active.
124 extern uint8_t append_win(struct WinMeta * wmeta, struct Win * w);
125 extern uint8_t suspend_win(struct WinMeta * wmeta, struct Win * w);
129 /* Apply scrolling offset "new_offset" to virtual screen if it is sane, i.e.
130 * it's equal/greater zero and does not push the view (further) beyond the
131 * virtual screen's border. If the view is already beyond the virtual screen's
132 * border due to it having shrunk after suspension of windows, only allow view
133 * movement leftwards.
135 extern void reset_pad_offset(struct WinMeta * wmeta, uint16_t new_offset);
139 /* Apply new size "size" to the active window, but only if it provides for at
140 * least one cell width/height and is in height at least one cell smaller than
141 * the screen's vertical height (to provide space for the title bar). Does
142 * nothing if no window is active.
144 extern uint8_t resize_active_win(struct WinMeta * wmeta, struct yx_uint16 size);
148 /* Cycle active window selection forwards ("dir" == "f") or backwards (any
149 * other "dir"). Wrap around in the windows chain if start / end of it is met.
150 * Does nothing if no window is active.
152 extern void cycle_active_win(struct WinMeta * wmeta, char dir);
156 /* Move active window forwards ("dir" == "f") or backwards (any other "dir").
157 * Wrap around in the window chain if start / end of it is met. Does nothing if
158 * no window is active.
160 extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir);
164 /* Draw virtual screen including all windows. Also add scroll hints (see comment
165 * on draw_scroll_hint()) for where the edges of the terminal screen hit
166 * non-edges of and inside the virtual screen. Then update the terminal screen.
168 extern uint8_t draw_all_wins(struct WinMeta * wmeta);
172 /* Draw scroll hint (a line stating that there is more to see on scrolling
173 * further into a certain direction) into "frame" at position "pos" (describing
174 * a column or a row dependent on "dir" being *either* "<"/">" *or* something
175 * else). It will consist of a line of "dir" symbols bracketing a descriptive
176 * text stating the number of rows/columns further available beyond the hint.
178 extern uint8_t draw_scroll_hint(struct Frame * frame, uint16_t pos,
179 uint32_t dist, char dir);