+/* windows.h
+ *
+ * A tiled window manager for the terminal.
+ *
+ * It provides a virtual screen that can be scrolled horizontally and may
+ * contain any number of windows that can be appeared, disappeared, resized and
+ * (somewhat) moved around. They have borders and a title bar and are positioned
+ * (in a bizarre fashion, see below) automatically.
+ *
+ * Windows can be almost any width (number has to fit into 16 bits); the virtual
+ * screen grows with them as needed -- but only horizontally. Their height is
+ * limited by the height of the terminal screen.
+ *
+ * Positioning of windows can only indirectly be influenced: by resizing them,
+ * and by shifting their relative position inside the (currently invisible)
+ * chain that the window manager treats their plurality as. The first window
+ * goes into the upper left corner of the virtual screen. Further visible
+ * windows are fitted left-aligned below their (chain-wise) closest predecessor
+ * that thrones over enough space to fit them in; failing that, they are placed
+ * to the right of the window with the rightmost border.
+ *
+ * TODO: Think up a more intuitive window positioning algorithm or at least make
+ * the chain that windows are positioned by visible.
+ *
+ * TODO: Ensure there are only windows as many / as big as fit into the maximum
+ * size of the virtual screen.
+ */
+
#ifndef WINDOWS_H
#define WINDOWS_H
-#include <stdint.h>
-#include <ncurses.h>
-#include "yx_uint16.h"
-
-struct Frame {
- WINDOW * curses_win;
- struct yx_uint16 size; };
-
-struct WinMeta {
- WINDOW * screen;
- uint16_t pad_offset;
- struct Frame pad;
- struct Win * chain_start;
- struct Win * chain_end;
- struct Win * active; };
-
-struct Win {
- struct Win * prev;
- struct Win * next;
- struct yx_uint16 start;
- struct Frame frame;
- char * title;
- void (* draw) (struct Win *);
- void * data; };
-
-extern struct WinMeta init_win_meta (WINDOW *);
-extern struct Win init_win (struct WinMeta *, char *, void *, void *);
-extern void append_win (struct WinMeta *, struct Win *);
-extern void suspend_win (struct WinMeta *, struct Win *);
-extern void draw_scroll_hint (struct Frame *, uint16_t, uint32_t, char);
-extern void draw_all_wins (struct WinMeta *);
-extern void resize_active_win (struct WinMeta *, struct yx_uint16);
-extern void cycle_active_win (struct WinMeta *, char);
-extern void shift_active_win (struct WinMeta *, char);
-extern void reset_pad_offset (struct WinMeta *, uint16_t);
+
+
+#include <stdint.h> /* for uint8_t, uint16_t, uint32_t */
+#include <ncurses.h> /* for the WINDOW typedef */
+#include "yx_uint16.h" /* for yx_uint16 coordinates */
+
+
+/* Individual windows consist of potential (real if window is visible) ncurses
+ * WINDOWs wrapped inside Frame structs (that keep a window's designated size
+ * even when it is invisible) wrapped inside metadata-rich Win structs. Win
+ * structs are chained into a linked list of all the windows visible on the
+ * virtual screen and also contain pointers to what content is to be drawn
+ * inside the window, and by use of what method.
+ */
+
+struct Frame
+{
+ WINDOW * curses_win;
+ struct yx_uint16 size; /* the size curses_win fits into; for the virtual */
+}; /* screen padframe: the terminal screen size */
+
+struct Win
+{
+ struct Win * _prev; /* INTERNAL */ /* _prev == _next == 0 if */
+ struct Win * _next; /* INTERNAL */ /* Win is outside the chain */
+ struct yx_uint16 _start; /* INTERNAL: upper left corner of WINDOW */
+ char * _title; /* INTERNAL: title for window title bar */
+ void (* _draw) (struct Win *); /* INTERNAL: how to draw window content */
+ struct Frame frame;
+ void * data; /* window content to be drawn by _draw() */
+};
+
+
+
+/* The window manager's parent struct WinMeta provides the virtual screen and a
+ * representation of the terminal screen. It also anchors start and end of the
+ * windows chain.
+ */
+struct WinMeta
+{
+ WINDOW * _screen; /* INTERNAL: terminal screen */
+ struct Win * _chain_start; /* INTERNAL: first Win, ._prev to point to 0 */
+ struct Win * _chain_end; /* INTERNAL: last Win, ._next to point to 0 */
+ uint16_t pad_offset; /* number of cells view is moved to the right */
+ struct Frame padframe; /* virtual screen fitted into terminal screen */
+ struct Win * active; /* Win highlighted/selected for manipulation */
+};
+
+
+
+/* Initialize empty WinMeta "wmeta" on the terminal "screen". Note that
+ * emptiness is marked by WinMeta.chain_start=0. Other struct values are also
+ * initialized 0, except for the virtual screen (terminal screen height, width =
+ * 1) and its terminal-sized frame.
+ *
+ * Returns 0 on success, 1 on (ncurses newpad() memory allocation) error.
+ */
+extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta * wmeta);
+
+
+
+/* Create a window below inside "wmeta" titled "title" of "height" and "width"
+ * and appointing "func"() to interpret and draw the content stored at "data"
+ * if the window is visible.
+ *
+ * A value for "width" <1 will trigger a fallback to width=1. A "height" <1 or
+ * larger than the maximum window height possible within the virtual screen will
+ * trigger a fallback to the maximum height possible (i.e. pass a "height" of 0
+ * to initialize the window to its largest possible height).
+ *
+ * Other values of the Win struct will be initialized to 0. The window will stay
+ * invisible until appended to the chain of visible windows via append_win().
+ */
+extern struct Win init_win(struct WinMeta * wmeta, char * title,
+ uint16_t height, uint16_t width,
+ void * data, void * func);
+
+
+
+/* Append/suspend window "w" to/from chain of visible windows in "wmeta".
+ * Appended windows will become active. Suspended active windows will move the
+ * active window selection to their successor in the window chain or, failing
+ * that, their predecessor; if no window remains, none will be active.
+ *
+ * Return 0 on success, and 1 on (ncurses window/pad memory allocation) error.
+ */
+extern uint8_t append_win(struct WinMeta * wmeta, struct Win * w);
+extern uint8_t suspend_win(struct WinMeta * wmeta, struct Win * w);
+
+
+
+/* Apply scrolling offset "new_offset" to virtual screen if it is sane, i.e.
+ * it's equal/greater zero and does not push the view (further) beyond the
+ * virtual screen's border. If the view is already beyond the virtual screen's
+ * border due to it having shrunk after suspension of windows, only allow view
+ * movement leftwards.
+ */
+extern void reset_pad_offset(struct WinMeta * wmeta, uint16_t new_offset);
+
+
+
+/* Apply new size "size" to the active window, but only if it provides for at
+ * least one cell width/height and is in height at least one cell smaller than
+ * the screen's vertical height (to provide space for the title bar).
+ *
+ * Returns 0 on success, 1 on (ncurses window/pad memory allocation) error.
+ */
+extern uint8_t resize_active_win(struct WinMeta * wmeta, struct yx_uint16 size);
+
+
+
+/* Cycle active window selection forwards (set dir="n") or backwards. Wrap
+ * around in the windows chain if start / end of it is met.
+ */
+extern void cycle_active_win(struct WinMeta * wmeta, char dir);
+
+
+
+/* Move active window forwards (set dir="f") or backwards (set dir="b"). Wrap
+ * around in the window chain if start / end of it is met.
+ *
+ * Returns 0 on success, 1 on (ncurses window/pad memory allocation) error.
+ */
+extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir);
+
+
+
+/* Draw virtual screen including all windows. Also add scroll hints (see comment
+ * on draw_scroll_hint()) for where the edges of the terminal screen hit
+ * non-edges of and inside the virtual screen. Then update the terminal screen.
+ *
+ * Returns 0 on success, 1 on error (of scroll hint text memory allocation).
+ */
+extern uint8_t draw_all_wins(struct WinMeta * wmeta);
+
+
+
+/* Draw scroll hint (a line stating that there is more to see on scrolling
+ * further into a certain direction) into "frame" at position "pos" (describing
+ * a column or a row dependent on "dir" being *either* "<"/">" *or* something
+ * else). It will consist of a line of "dir" symbols bracketing a descriptive
+ * text stating the number of rows/columns further available beyond the hint.
+ *
+ * Return 0 on success, and 1 on error (of scroll hint text memory allocation).
+ */
+extern uint8_t draw_scroll_hint(struct Frame * frame, uint16_t pos,
+ uint32_t dist, char dir);
+
+
#endif
projects / plomrogue / blobdiff