+/* 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 and only up to 2^16
+ * cells. Their height is limited by the height of the terminal screen, which
+ * must also fit into 2^16 cells.
+ *
+ * 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.
+ *
+ * Functions that return uint8_t return these error codes:
+ * 0 - success
+ * 1 - memory allocation error
+ * 2 - would force virtual screen to grow beyond width or height of 2^16 cells
+ *
+ * TODO: Expose less internals to the API.
+ *
+ * TODO: Think up a more intuitive window positioning algorithm or at least make
+ * the chain that windows are positioned by visible.
+ */
+
#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 only if window is visible
+ * inside the virtual screen) 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 /* If Frame is Win's "frame", "size" is the */
+{ /* designated size of curses_win's ncurses WINDOW. */
+ WINDOW * curses_win; /* If Frame is WinMeta's "padframe", curses_win is */
+ struct yx_uint16 size; /* the ncurses pad representing the virtual screen */
+}; /* and "size" desribes the terminal screen size. */
+
+struct Win
+{
+ struct Win * prev; /* chain pointers; if 0, they mark the start or end */
+ struct Win * next; /* of the chain; if both are 0, Win is outside chain */
+ struct yx_uint16 start; /* upper left corner of "frame" WINDOW */
+ char * title; /* title to be used in window title bar */
+ void (* draw) (struct Win *); /* how to draw window content ("data") */
+ struct Frame frame;
+ void * data; /* window content to be drawn by _draw() */
+};
+
+
+
+/* The window manager's parent struct WinMeta contains the virtual screen,
+ * relates it to the terminal screen and anchors the chain of visible windows.
+ */
+struct WinMeta
+{
+ WINDOW * screen; /* ncurses' pointer to the terminal screen */
+ struct Win * chain_start; /* first Win in chain; its _prev == 0 */
+ struct Win * chain_end; /* last Win in chain; its _next == 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 members are also
+ * initialized 0, except for the virtual screen (height = that of the terminal
+ * screen; width = 1) amd its frame sized to the size of the terminal screen.
+ */
+extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta ** wmeta);
+
+
+
+/* Initialize a window child of "wmeta" to "title", "height" and "width" and
+ * appointing "func"() to interpret and draw the content stored at "data" when
+ * the window is visible.
+ *
+ * Pass 0 for "width" to make the window as wide as the terminal screen. Pass
+ * negative values for "width" to make the width so many cells smaller than that
+ * of the terminal screen. Pass 0 for "height" to give the window the maximum
+ * allowed height: one cell smaller than that of the terminal screen. Pass
+ * negative values to make the window width so many cells smaller than that of
+ * the terminal screen. The maximum allowed height is also applied for positive
+ * values that exceed it or negative values that would reduce the window height
+ * < 1 cell.
+ *
+ * Other members of the Win struct are initialized to 0.
+ */
+extern uint8_t init_win(struct WinMeta * wmeta, struct Win ** w, char * title,
+ int16_t height, int16_t width,
+ void * data, void * func);
+
+
+
+/* Free allocated memory for an initialized Win / WinMeta struct. */
+extern void free_winmeta(struct WinMeta * wmeta);
+extern void free_win(struct Win * win);
+
+
+
+/* Append/suspend window "w" to/from chain of visible windows below "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.
+ */
+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). Does
+ * nothing if no window is active.
+ */
+extern uint8_t resize_active_win(struct WinMeta * wmeta, struct yx_uint16 size);
+
+
+
+/* Cycle active window selection forwards ("dir" == "f") or backwards (any
+ * other "dir"). Wrap around in the windows chain if start / end of it is met.
+ * Does nothing if no window is active.
+ */
+extern void cycle_active_win(struct WinMeta * wmeta, char dir);
+
+
+
+/* Move active window forwards ("dir" == "f") or backwards (any other "dir").
+ * Wrap around in the window chain if start / end of it is met. Does nothing if
+ * no window is active.
+ */
+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.
+ */
+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 "dist" as the number of rows/columns further available beyond
+ * the hint.
+ */
+extern uint8_t draw_scroll_hint(struct Frame * frame, uint16_t pos,
+ uint32_t dist, char dir);
+
+
#endif
projects / plomrogue / blobdiff