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, which
13 * must also fit into 2^16 cells.
15 * Positioning of windows can only indirectly be influenced: by resizing them,
16 * and by shifting their relative position inside the (currently invisible)
17 * chain that the window manager treats their plurality as. The first window
18 * goes into the upper left corner of the virtual screen. Further visible
19 * windows are fitted left-aligned below their (chain-wise) closest predecessor
20 * that thrones over enough space to fit them in; failing that, they are placed
21 * to the right of the window with the rightmost border.
23 * Functions that return uint8_t return these error codes:
25 * 1 - memory allocation error
26 * 2 - would force virtual screen to grow beyond width or height of 2^16 cells
28 * TODO: Expose less internals to the API.
30 * TODO: Think up a more intuitive window positioning algorithm or at least make
31 * the chain that windows are positioned by visible.
39 #include <stdint.h> /* for uint8_t, uint16_t, uint32_t */
40 #include <ncurses.h> /* for the WINDOW typedef */
41 #include "yx_uint16.h" /* for yx_uint16 coordinates */
45 /* Individual windows consist of potential (real only if window is visible
46 * inside the virtual screen) ncurses WINDOWs wrapped inside Frame structs (that
47 * keep a window's designated size even when it is invisible) wrapped inside
48 * metadata-rich Win structs. Win structs are chained into a linked list of all
49 * the windows visible on the virtual screen and also contain pointers to what
50 * content is to be drawn inside the window, and by use of what method.
53 struct Frame /* If Frame is Win's "frame", "size" is the */
54 { /* designated size of curses_win's ncurses WINDOW. */
55 WINDOW * curses_win; /* If Frame is WinMeta's "padframe", curses_win is */
56 struct yx_uint16 size; /* the ncurses pad representing the virtual screen */
57 }; /* and "size" desribes the terminal screen size. */
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 void * data; /* window content to be drawn by _draw() */
72 /* The window manager's parent struct WinMeta contains the virtual screen,
73 * relates it to the terminal screen and anchors the chain of visible windows.
77 WINDOW * screen; /* ncurses' pointer to the terminal screen */
78 struct Win * chain_start; /* first Win in chain; its _prev == 0 */
79 struct Win * chain_end; /* last Win in chain; its _next == 0 */
80 uint16_t pad_offset; /* number of cells view is moved to the right */
81 struct Frame padframe; /* virtual screen fitted into terminal screen */
82 struct Win * active; /* Win highlighted/selected for manipulation */
87 /* Initialize empty WinMeta "wmeta" on the terminal "screen". (Note that
88 * emptiness is marked by WinMeta.chain_start=0.) Other struct members are also
89 * initialized 0, except for the virtual screen (height = that of the terminal
90 * screen; width = 1) amd its frame sized to the size of the terminal screen.
92 extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta ** wmeta);
96 /* Initialize a window child of "wmeta" to "title", "height" and "width" and
97 * appointing "func"() to interpret and draw the content stored at "data" when
98 * the window is visible.
100 * Pass 0 for "width" to make the window as wide as the terminal screen. Pass
101 * negative values for "width" to make the width so many cells smaller than that
102 * of the terminal screen. Pass 0 for "height" to give the window the maximum
103 * allowed height: one cell smaller than that of the terminal screen. Pass
104 * negative values to make the window width so many cells smaller than that of
105 * the terminal screen. The maximum allowed height is also applied for positive
106 * values that exceed it or negative values that would reduce the window height
109 * Other members of the Win struct are initialized to 0.
111 extern uint8_t init_win(struct WinMeta * wmeta, struct Win ** w, char * title,
112 int16_t height, int16_t width,
113 void * data, void * func);
117 /* Free allocated memory for an initialized Win / WinMeta struct. */
118 extern void free_winmeta(struct WinMeta * wmeta);
119 extern void free_win(struct Win * win);
123 /* Append/suspend window "w" to/from chain of visible windows below "wmeta".
124 * Appended windows will become active. Suspended active windows will move the
125 * active window selection to their successor in the window chain or, failing
126 * that, their predecessor; if no window remains, none will be active.
128 extern uint8_t append_win(struct WinMeta * wmeta, struct Win * w);
129 extern uint8_t suspend_win(struct WinMeta * wmeta, struct Win * w);
133 /* Apply scrolling offset "new_offset" to virtual screen if it is sane, i.e.
134 * it's equal/greater zero and does not push the view (further) beyond the
135 * virtual screen's border. If the view is already beyond the virtual screen's
136 * border due to it having shrunk after suspension of windows, only allow view
137 * movement leftwards.
139 extern void reset_pad_offset(struct WinMeta * wmeta, uint16_t new_offset);
143 /* Apply new size "size" to the active window, but only if it provides for at
144 * least one cell width/height and is in height at least one cell smaller than
145 * the screen's vertical height (to provide space for the title bar). Does
146 * nothing if no window is active.
148 extern uint8_t resize_active_win(struct WinMeta * wmeta, struct yx_uint16 size);
152 /* Cycle active window selection forwards ("dir" == "f") or backwards (any
153 * other "dir"). Wrap around in the windows chain if start / end of it is met.
154 * Does nothing if no window is active.
156 extern void cycle_active_win(struct WinMeta * wmeta, char dir);
160 /* Move active window forwards ("dir" == "f") or backwards (any other "dir").
161 * Wrap around in the window chain if start / end of it is met. Does nothing if
162 * no window is active.
164 extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir);
168 /* Draw virtual screen including all windows. Also add scroll hints (see comment
169 * on draw_scroll_hint()) for where the edges of the terminal screen hit
170 * non-edges of and inside the virtual screen. Then update the terminal screen.
172 extern uint8_t draw_all_wins(struct WinMeta * wmeta);
176 /* Draw scroll hint (a line stating that there is more to see on scrolling
177 * further into a certain direction) into "frame" at position "pos" (describing
178 * a column or a row dependent on "dir" being *either* "<"/">" *or* something
179 * else). It will consist of a line of "dir" symbols bracketing a descriptive
180 * text stating "dist" as the number of rows/columns further available beyond
183 extern uint8_t draw_scroll_hint(struct Frame * frame, uint16_t pos,
184 uint32_t dist, char dir);