X-Git-Url: https://plomlompom.com/repos/?a=blobdiff_plain;f=src%2Fwindows.c;h=df9674355a21a52985d554e8b1b0130b21c73639;hb=550d22ec0c3f530f5d317746f3f7e75251a1de4b;hp=181247caf619a682cae2ec44e64bb6457d453c3f;hpb=d7c46fb1de25edd8782fbc7642be71e5e54deab2;p=plomrogue

diff --git a/src/windows.c b/src/windows.c
index 181247c..df96743 100644
--- a/src/windows.c
+++ b/src/windows.c
@@ -1,299 +1,702 @@
+/* windows.c */
+
 #include "windows.h"
-#include <stdint.h>
-#include <ncurses.h>
-#include <stdlib.h>
-#include <string.h>
-
-struct Corners {
-  struct yx_uint16 tl;
-  struct yx_uint16 tr;
-  struct yx_uint16 bl;
-  struct yx_uint16 br; };
-
-static void refit_pad (struct WinMeta *);
-static void place_win (struct WinMeta *, struct Win *);
-static void update_wins (struct WinMeta *, struct Win *);
-static void destroy_win (struct Win *);
-static void draw_wins_borders (struct Win *, struct Win *, struct Corners *, uint16_t);
-static void draw_win_borders (struct Win *, char);
-static void draw_wins (struct Win *);
-
-extern struct WinMeta init_win_meta (WINDOW * screen) {
-// Create and populate WinMeta struct with sane default values.
-  struct WinMeta wmeta;
-  wmeta.screen = screen;
-  wmeta.pad.size.y = getmaxy(screen);
-  wmeta.pad.size.x = getmaxx(screen);
-  wmeta.chain_start = 0;
-  wmeta.chain_end = 0;
-  wmeta.pad_offset = 0;
-  wmeta.pad.curses_win = newpad(wmeta.pad.size.y, 1);
-  wmeta.active = 0;
-  return wmeta; }
-
-extern struct Win init_win (struct WinMeta * wmeta, char * title, void * data, void * func) {
-// Create and populate Win struct with sane default values.
-  struct Win w;
-  w.prev = 0;
-  w.next = 0;
-  w.frame.curses_win = 0;
-  w.title = title;
-  w.frame.size.x = 20;
-  w.frame.size.y = wmeta->pad.size.y - 1;
-  w.data = data;
-  w.draw = func;
-  return w; }
-
-extern void append_win (struct WinMeta * wmeta, struct Win * w) {
-// Append win to window chain. Set active, if first window. Update geometry of windows from new window on.
-  if (0 != wmeta->chain_start) {
-    w->prev = wmeta->chain_end;
-    wmeta->chain_end->next = w; }
-  else {
-    wmeta->active = w;
-    wmeta->chain_start = w; }
-  wmeta->chain_end = w;
-  update_wins(wmeta, w); }
-
-static void refit_pad (struct WinMeta * wmeta) {
-// Fit pad width to minimum width demanded by current windows' geometries.
-  uint16_t lastwincol = 0;
-  struct Win * w_p = wmeta->chain_start;
-  while (w_p != 0) {
-    if (w_p->start.x + w_p->frame.size.x > lastwincol + 1)
-      lastwincol = w_p->start.x + w_p->frame.size.x - 1;
-    w_p = w_p->next; }
-  if (getmaxx(wmeta->pad.curses_win) != lastwincol)
-    wresize(wmeta->pad.curses_win, getmaxy(wmeta->pad.curses_win), lastwincol + 2); }
-
-extern void suspend_win (struct WinMeta * wmeta, struct Win * w) {
-// Destroy win, suspend from chain. Update geometry of following rows and pad, as well as activity selection.
-  destroy_win(w);
-  if (wmeta->chain_start != w)         // Give win's position in the chain to element next to it in the chain.
-    w->prev->next = w->next;
-  else
-    wmeta->chain_start = w->next;
-  char pad_refitted = 0;
-  if (wmeta->chain_end != w) {                      // Let chain element next to win know its new predecessor.
-    w->next->prev = w->prev;
-    if (wmeta->active == w)                               // If win was active, shift active window pointer to
-      wmeta->active = w->next;                            // the next chain element, if that is a window ...
-    update_wins(wmeta, w->next);
-    pad_refitted = 1; }
-  else {
-    wmeta->chain_end = w->prev;
-    if (wmeta->active == w)                                            // ... or else to the previous element.
-      wmeta->active = w->prev; }
-  w->prev = 0;
-  w->next = 0;
-  if (0 == pad_refitted)                                                            // Refit pad if necessary.
-    refit_pad(wmeta); }
-
-static void place_win (struct WinMeta * wmeta, struct Win * w) {
-// Based on position and sizes of previous window, find fitting place for current window.
-  w->start.x = 0;                                  // if window is first in chain, place it on top-left corner
-  w->start.y = 1;
-  if (0 != w->prev) {
-    struct Win * w_top = w->prev;
-    while (w_top->start.y != 1)
-      w_top = w_top->prev;                                       // else, default to placing window in new top
-    w->start.x = w_top->start.x + w_top->frame.size.x + 1;       // column to the right of the last one
-    uint16_t w_prev_maxy = w->prev->start.y + getmaxy(w->prev->frame.curses_win);
-    if (w->frame.size.x <= w->prev->frame.size.x && w->frame.size.y < wmeta->pad.size.y - w_prev_maxy) {
-      w->start.x = w->prev->start.x;                       // place window below previous window if it fits
-      w->start.y = w_prev_maxy + 1; }                      // vertically and is not wider than its predecessor
-    else {
-      struct Win * w_up = w->prev;
-      struct Win * w_upup = w_up;
-      uint16_t widthdiff;
-      while (w_up != w_top) {
-        w_upup = w_up->prev;
-        while (1) {
-          if (w_up->start.y != w_upup->start.y)
-            break;
-          w_upup = w_upup->prev; }
-        w_prev_maxy = w_upup->start.y + getmaxy(w_upup->frame.curses_win);
-        widthdiff = (w_upup->start.x + w_upup->frame.size.x) - (w_up->start.x + w_up->frame.size.x);
-        if (w->frame.size.y < wmeta->pad.size.y - w_prev_maxy && w->frame.size.x < widthdiff) {
-          w->start.x = w_up->start.x + w_up->frame.size.x + 1 ; // else try to open new sub column under
-          w->start.y = w_prev_maxy + 1;                        // last window below which enough space remains
-          break; }
-        w_up = w_upup; } } } }
-
-static void update_wins (struct WinMeta * wmeta, struct Win * w) {
-// Update geometry of win and its next of kin. Destroy (if visible), (re-)build window. If need, resize pad.
-  if (0 != w->frame.curses_win)
-    destroy_win (w);
-  place_win(wmeta, w);
-  refit_pad(wmeta);
-  w->frame.curses_win=subpad(wmeta->pad.curses_win, w->frame.size.y, w->frame.size.x, w->start.y, w->start.x);
-  if (0 != w->next)
-    update_wins (wmeta, w->next); }
-
-static void destroy_win (struct Win * w) {
-// Delete window.
-  delwin(w->frame.curses_win);
-  w->frame.curses_win = 0; }
-
-static void draw_win_borders (struct Win * w, char active) {
-// Draw borders of window win, including title. Decorate in a special way if window is marked as active.
-  uint16_t y, x;
-  for (y = w->start.y; y <= w->start.y + w->frame.size.y; y++) {
-    mvwaddch(wgetparent(w->frame.curses_win), y, w->start.x - 1, '|');
-    mvwaddch(wgetparent(w->frame.curses_win), y, w->start.x + w->frame.size.x, '|'); }
-  for (x = w->start.x; x <= w->start.x + w->frame.size.x; x++) {
-    mvwaddch(wgetparent(w->frame.curses_win), w->start.y - 1, x, '-');
-    mvwaddch(wgetparent(w->frame.curses_win), w->start.y + w->frame.size.y, x, '-'); }
-  char min_title_length_visible = 3;        // 1 char minimal, plus 2 chars for decoration left/right of title
-  if (w->frame.size.x >= min_title_length_visible) {
-    uint16_t title_offset = 0;
-    if (w->frame.size.x > strlen(w->title) + 2)
-      title_offset = (w->frame.size.x - (strlen(w->title) + 2)) / 2;                  // + 2 is for decoration
-    uint16_t length_visible = strnlen(w->title, w->frame.size.x - 2);
-    char title[length_visible + 3];
-    char decoration = ' ';
-    if (1 == active)
-      decoration = '$';
-    memcpy(title + 1, w->title, length_visible);
-    title[0] = title[length_visible + 1] = decoration;
-    title[length_visible + 2] = '\0';
-    mvwaddstr(wgetparent(w->frame.curses_win), w->start.y - 1, w->start.x + title_offset, title); } }
-
-static void draw_wins_borders (struct Win * w, struct Win * w_active, struct Corners * corners, uint16_t i) {
-// Call draw_win_borders() for all windows in chain from win on. Save current window's border corners.
-  char active = 0;
-  if (w == w_active)
-    active = 1;
-  draw_win_borders(w, active);
-  corners[i].tl.y = w->start.y - 1;
-  corners[i].tl.x = w->start.x - 1;
-  corners[i].tr.y = w->start.y - 1;
-  corners[i].tr.x = w->start.x + w->frame.size.x;
-  corners[i].bl.y = w->start.y + w->frame.size.y;
-  corners[i].bl.x = w->start.x - 1;
-  corners[i].br.y = w->start.y + w->frame.size.y;
-  corners[i].br.x = w->start.x + w->frame.size.x;
-  if (0 != w->next) {
-    draw_wins_borders (w->next, w_active, corners, i + 1); } }
-
-static void draw_wins (struct Win * w) {
-// Draw contents of all windows in window chain from win on.
-  w->draw(w);
-  if (0 != w->next) {
-    draw_wins (w->next); } }
-
-extern void draw_scroll_hint (struct Frame * frame, uint16_t pos, uint32_t dist, char dir) {
-// Draw scroll hint into frame at pos (row or col dependend on dir), mark distance of dist cells into dir.
-  char more[] = "more";
-  char unit_cols[] = "columns";
-  char unit_rows[] = "lines";
-  uint16_t dsc_space = frame->size.x;
-  char * unit = unit_rows;
-  if ('<' == dir || '>' == dir) {
-    dsc_space = frame->size.y;
-    unit = unit_cols; }
-  char * scrolldsc = malloc((4 * sizeof(char)) + strlen(more) + strlen(unit) + 10);  // 10 = uint32 max strlen
-  sprintf(scrolldsc, " %d %s %s ", dist, more, unit);
-  char offset = 1, q;
-  if (dsc_space > strlen(scrolldsc) + 1)
-    offset = (dsc_space - strlen(scrolldsc)) / 2;
-  chtype symbol;
-  for (q = 0; q < dsc_space; q++) {
-    if (q >= offset && q < strlen(scrolldsc) + offset)
-      symbol = scrolldsc[q - offset] | A_REVERSE;
+#include <stdint.h>    /* for uint8_t, uint16_t, uint32_t, UINT16_MAX */
+#include <ncurses.h>   /* for typedefs WINDOW, chtype, wresize(), getmaxx(), */
+                       /* getmaxy(), supbad(), delwin(), mvwaddch(),         */
+                       /* mvwaddstr(), newpad(), wnoutrefres(), erase(),     */
+                       /* werase(), pnoutrefresh(), doupdate()               */
+#include <stdlib.h>    /* for malloc(), free() */
+#include <string.h>    /* for strlen(), strnlen(), memcpy() */
+#include "yx_uint16.h" /* for yx_uint16 coordinates */
+
+
+
+/* Fit virtual screen's width to minimum width demanded by current windows'
+ * geometries.
+ */
+static uint8_t refit_pad(struct WinMeta * wmeta);
+
+
+
+/* Update geometry (sizes, positions) of window "w" and its successors in the
+ * window chain. For the positioning algorithm place_win() is used.
+ */
+static uint8_t update_wins(struct WinMeta * wmeta, struct Win * w);
+static void place_win(struct WinMeta * wmeta, struct Win * w);
+
+
+
+/* Destroy window "w"'s ncurses WINDOW (and set w.Frame.curses_win to 0). */
+static void destroy_win(struct Win * w);
+
+
+
+/* Draw contents of all windows in window chain from window "w" onwards. */
+static void draw_wins(struct Win * w);
+
+
+
+/* draw_win_borderlines() draws the vertical and horizontal borders of window
+ * "w" sans corners into the virtual screen "pad", and draws the top border
+ * line as the windows' title bar (highlighted if the window is described
+ * active by "active" being == 1).
+ *
+ * draw_wins_borderlines() calls draw_win_borderlines() recursively on all
+ * windows from "w" on. "w_active" is a pointer to the one window that
+ * draw_win_borderlines() is supposed to handle as the active window.
+ *
+ * Finally, draw_wins_bordercorners() draws into "pad" the borders of window "w"
+ * and all its successors.
+ */
+static void draw_win_borderlines(struct Win * w, char active, WINDOW * pad);
+static void draw_wins_borderlines(struct Win * w, struct Win * w_active,
+                                  WINDOW * pad);
+static void draw_wins_bordercorners(struct Win * w, WINDOW * pad);
+
+
+
+/* Shift active window forwards / backwards in window chain. */
+static void shift_win_forward(struct WinMeta * wmeta);
+static void shift_win_backward(struct WinMeta * wmeta);
+
+
+
+static uint8_t refit_pad(struct WinMeta * wmeta)
+{
+    /* Determine rightmost window column. */
+    uint32_t lastwincol = 0;
+    struct Win * w_p = wmeta->chain_start;
+    while (w_p != 0)
+    {
+        if ((uint32_t) w_p->start.x + (uint32_t) w_p->frame.size.x
+            > lastwincol + 1)
+        {
+            lastwincol = (uint32_t) w_p->start.x
+                         + (uint32_t) w_p->frame.size.x - 1;
+        }
+        w_p = w_p->next;
+    }
+
+    /* Only resize the pad if the rightmost window column has changed. */
+    if (getmaxx(wmeta->padframe.curses_win) + 1 != lastwincol)
+    {
+        if (lastwincol + 2 > UINT16_MAX)
+        {
+            return 2;
+        }
+        return (ERR == wresize(wmeta->padframe.curses_win,
+                               getmaxy(wmeta->padframe.curses_win),
+                               lastwincol + 2));
+    }
+    return 0;
+}
+
+
+
+static uint8_t update_wins(struct WinMeta * wmeta, struct Win * w)
+{
+    if (0 != w->frame.curses_win)
+    {
+        destroy_win(w);
+    }
+    place_win(wmeta, w);
+    uint8_t test_refit = refit_pad(wmeta);
+    if (0 != test_refit)
+    {
+        return test_refit;
+    }
+    WINDOW * subpad_test = subpad(wmeta->padframe.curses_win,
+                                  w->frame.size.y, w->frame.size.x,
+                                  w->start.y, w->start.x);
+    if (NULL == subpad_test)
+    {
+        return 1;
+    }
+    w->frame.curses_win = subpad_test;
+    if (0 != w->next)
+    {
+        return update_wins(wmeta, w->next);
+    }
+    return 0;
+}
+
+
+
+static void place_win(struct WinMeta * wmeta, struct Win * w)
+{
+    /* First window goes into the upper-left corner. */
+    w->start.x = 0;
+    w->start.y = 1;                             /* Leave space for title bar. */
+    if (0 != w->prev)
+    {
+
+        /* Non-first window fallbacks to: fit rightwards of rightmost border. */
+        struct Win * w_top = w->prev;
+        while (w_top->start.y != 1)
+        {
+            w_top = w_top->prev;
+        }
+        w->start.x = w_top->start.x + w_top->frame.size.x + 1;
+
+        /* Fit window below its predecessor if that one directly thrones over
+         * empty space wide and high enough.
+         */
+        uint16_t w_prev_maxy = w->prev->start.y
+                               + getmaxy(w->prev->frame.curses_win);
+        if (   w->frame.size.x <= w->prev->frame.size.x
+            && w->frame.size.y <  wmeta->padframe.size.y - w_prev_maxy)
+        {
+            w->start.x = w->prev->start.x;
+            w->start.y = w_prev_maxy + 1;
+        }
+
+        /* Failing that, try to open a new sub column below the nearest
+         * predecessor window that thrones over enough empty space.
+         */
+        else
+        {
+            struct Win * w_up = w->prev;
+            struct Win * w_upup = w_up;
+            uint16_t widthdiff;
+            while (w_up != w_top)
+            {
+                w_upup = w_up->prev;
+                while (1)
+                {
+                    if (w_up->start.y != w_upup->start.y)
+                    {
+                        break;
+                    }
+                    w_upup = w_upup->prev;
+                }
+                w_prev_maxy = w_upup->start.y
+                              + getmaxy(w_upup->frame.curses_win);
+                widthdiff = (w_upup->start.x + w_upup->frame.size.x)
+                            - (w_up->start.x + w_up->frame.size.x);
+                if (   w->frame.size.y < wmeta->padframe.size.y - w_prev_maxy
+                    && w->frame.size.x < widthdiff)
+                {
+                    w->start.x = w_up->start.x + w_up->frame.size.x + 1 ;
+                    w->start.y = w_prev_maxy + 1;
+                    break;
+                }
+                w_up = w_upup;
+            }
+        }
+    }
+}
+
+
+
+static void destroy_win(struct Win * w)
+{
+    delwin(w->frame.curses_win);
+    w->frame.curses_win = 0;
+}
+
+
+
+static void draw_wins(struct Win * w)
+{
+    w->draw(w);
+    if (0 != w->next)
+    {
+        draw_wins(w->next);
+    }
+}
+
+
+
+static void draw_win_borderlines(struct Win * w, char active, WINDOW * pad)
+{
+    /* Draw vertical and horizontal border lines. */
+    uint16_t y, x;
+    for (y = w->start.y; y <= w->start.y + w->frame.size.y; y++)
+    {
+        mvwaddch(pad, y, w->start.x - 1,               '|');
+        mvwaddch(pad, y, w->start.x + w->frame.size.x, '|');
+    }
+    for (x = w->start.x; x <= w->start.x + w->frame.size.x; x++)
+    {
+        mvwaddch(pad, w->start.y - 1,               x, '-');
+        mvwaddch(pad, w->start.y + w->frame.size.y, x, '-');
+    }
+
+    /* Draw as much as possible of the title into center of top border line. */
+    char min_title_length_visible = 3;  /* min. 1 char + 2 padding/decoration */
+    if (w->frame.size.x >= min_title_length_visible)
+    {
+        uint16_t title_offset = 0;
+        if (w->frame.size.x > strlen(w->title) + 2)
+        {
+            title_offset = (w->frame.size.x - (strlen(w->title) + 2)) / 2;
+        }                                    /* +2 is for padding/decoration */
+        uint16_t length_visible = strnlen(w->title, w->frame.size.x - 2);
+        char title[length_visible + 3];
+        char decoration = ' ';
+        if (1 == active)
+        {
+            decoration = '$';
+        }
+        memcpy(title + 1, w->title, length_visible);
+        title[0] = title[length_visible + 1] = decoration;
+        title[length_visible + 2] = '\0';
+        mvwaddstr(pad, w->start.y - 1, w->start.x + title_offset, title);
+    }
+}
+
+
+
+static void draw_wins_borderlines(struct Win * w, struct Win * w_active,
+                                  WINDOW * pad)
+{
+    char active = 0;
+    if (w == w_active)
+    {
+        active = 1;
+    }
+    draw_win_borderlines(w, active, pad);
+    if (0 != w->next)
+    {
+        draw_wins_borderlines(w->next, w_active, pad);
+    }
+}
+
+
+
+static void draw_wins_bordercorners(struct Win * w, WINDOW * pad)
+{
+    mvwaddch(pad, w->start.y - 1, w->start.x - 1, '+');
+    mvwaddch(pad, w->start.y - 1, w->start.x + w->frame.size.x, '+');
+    mvwaddch(pad, w->start.y + w->frame.size.y, w->start.x - 1, '+');
+    mvwaddch(pad,
+             w->start.y + w->frame.size.y, w->start.x + w->frame.size.x, '+');
+    if (0 != w->next)
+    {
+        draw_wins_bordercorners(w->next, pad);
+    }
+}
+
+
+
+static void shift_win_forward(struct WinMeta * wmeta)
+{
+    if (wmeta->active == wmeta->chain_end)
+    {
+        wmeta->chain_end = wmeta->active->prev;
+        wmeta->chain_end->next = 0;
+        wmeta->active->next = wmeta->chain_start;
+        wmeta->active->next->prev = wmeta->active;
+        wmeta->chain_start = wmeta->active;
+        wmeta->chain_start->prev = 0;
+    }
     else
-      symbol = dir | A_REVERSE;
-    if ('<' == dir || '>' == dir)
-      mvwaddch(frame->curses_win, q, pos, symbol);
+    {
+        struct Win * old_prev = wmeta->active->prev;
+        struct Win * old_next = wmeta->active->next;
+        if (wmeta->chain_end == wmeta->active->next)
+        {
+            wmeta->chain_end = wmeta->active;
+            wmeta->active->next = 0;
+        }
+        else
+        {
+            wmeta->active->next = old_next->next;
+            wmeta->active->next->prev = wmeta->active;
+        }
+        if (wmeta->chain_start == wmeta->active)
+        {
+            wmeta->chain_start = old_next;
+        }
+        else
+        {
+            old_prev->next = old_next;
+        }
+        old_next->prev = old_prev;
+        old_next->next = wmeta->active;
+        wmeta->active->prev = old_next;
+    }
+}
+
+
+
+static void shift_win_backward(struct WinMeta * wmeta)
+{
+    if (wmeta->active == wmeta->chain_start)
+    {
+        wmeta->chain_start = wmeta->active->next;
+        wmeta->chain_start->prev = 0;
+        wmeta->active->prev = wmeta->chain_end;
+        wmeta->active->prev->next = wmeta->active;
+        wmeta->chain_end = wmeta->active;
+        wmeta->chain_end->next = 0;
+    }
+    else
+    {
+        struct Win * old_prev = wmeta->active->prev;
+        struct Win * old_next = wmeta->active->next;
+        if (wmeta->chain_start == wmeta->active->prev)
+        {
+            wmeta->chain_start = wmeta->active;
+            wmeta->active->prev = 0;
+        }
+        else
+        {
+            wmeta->active->prev = old_prev->prev;
+            wmeta->active->prev->next = wmeta->active;
+        }
+        if (wmeta->chain_end == wmeta->active)
+        {
+            wmeta->chain_end = old_prev;
+        }
+        else
+        {
+            old_next->prev = old_prev;
+        }
+        old_prev->next = old_next;
+        old_prev->prev = wmeta->active;
+        wmeta->active->next = old_prev;
+    }
+}
+
+
+
+extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta ** wmp)
+{
+    struct WinMeta * wmeta = malloc(sizeof(struct WinMeta));
+    wmeta->screen              = screen;
+    uint32_t maxy_test         = getmaxy(screen);
+    uint32_t maxx_test         = getmaxx(screen);
+    if (maxy_test > UINT16_MAX || maxx_test > UINT16_MAX)
+    {
+        return 2;
+    }
+    wmeta->padframe.size.y     = maxy_test;
+    wmeta->padframe.size.x     = maxx_test;
+    wmeta->chain_start         = 0;
+    wmeta->chain_end           = 0;
+    wmeta->pad_offset          = 0;
+    WINDOW * pad_test          = newpad(wmeta->padframe.size.y, 1);
+    if (NULL == pad_test)
+    {
+        return 1;
+    }
+    wmeta->padframe.curses_win = pad_test;
+    wmeta->active              = 0;
+    *wmp = wmeta;
+    return 0;
+}
+
+
+
+extern uint8_t init_win(struct WinMeta * wmeta, struct Win ** wp, char * title,
+                        int16_t height, int16_t width,
+                        void * data, void * func)
+{
+    struct Win * w = malloc(sizeof(struct Win));
+    if (NULL == w)
+    {
+        return 1;
+    }
+    w->prev             = 0;
+    w->next             = 0;
+    w->frame.curses_win = 0;
+    w->title            = malloc(strlen(title) + 1);
+    if (NULL == w->title)
+    {
+        return 1;
+    }
+    sprintf(w->title, "%s", title);
+    w->data              = data;
+    w->draw             = func;
+    if      (0 < width)
+    {
+        w->frame.size.x = width;
+    }
+    else if (0 >= width)
+    {
+        w->frame.size.x = wmeta->padframe.size.x + width;
+    }
+    if      (0 < height && height <= wmeta->padframe.size.y - 1)
+    {
+        w->frame.size.y = height;
+    }
+    else if (0 >= height && wmeta->padframe.size.y + (height - 1) > 0)
+    {
+        w->frame.size.y = wmeta->padframe.size.y + (height - 1);
+    }
+    *wp = w;
+    return 0;
+}
+
+
+
+extern void free_winmeta(struct WinMeta * wmeta)
+{
+    delwin(wmeta->padframe.curses_win);
+    free(wmeta);
+}
+
+
+
+extern void free_win(struct Win * win)
+{
+    if (0 != win->frame.curses_win)
+    {
+        delwin(win->frame.curses_win);
+    }
+    free(win->title);
+    free(win);
+}
+
+
+
+extern uint8_t append_win(struct WinMeta * wmeta, struct Win * w)
+{
+    if (0 != wmeta->chain_start)
+    {
+        w->prev = wmeta->chain_end;
+        wmeta->chain_end->next = w;
+    }
+    else
+    {
+        wmeta->active = w;
+        wmeta->chain_start = w;
+    }
+    wmeta->chain_end = w;
+    return update_wins(wmeta, w);
+}
+
+
+
+extern uint8_t suspend_win(struct WinMeta * wmeta, struct Win * w)
+{
+    destroy_win(w);
+
+    if (wmeta->chain_start != w)
+    {
+        w->prev->next = w->next;
+    }
     else
-      mvwaddch(frame->curses_win, pos, q, symbol); }
-  free(scrolldsc); }
-
-extern void draw_all_wins (struct WinMeta * wmeta) {
-// Draw pad with all windows and their borders, plus scrolling hints.
-  erase();
-  wnoutrefresh(wmeta->screen);
-  werase(wmeta->pad.curses_win);
-  if (wmeta->chain_start) {
-    uint16_t n_wins = 1, i;
-    struct Win * win_p = wmeta->chain_start;
-    while (0 != win_p->next) {
-      win_p = win_p->next;
-      n_wins++; }
-    struct Corners * all_corners = malloc(sizeof(struct Corners) * n_wins);
-    draw_wins (wmeta->chain_start);
-    draw_wins_borders (wmeta->chain_start, wmeta->active, all_corners, 0);
-    for (i = 0; i < n_wins; i++) {
-      mvwaddch(wmeta->pad.curses_win, all_corners[i].tl.y, all_corners[i].tl.x, '+');
-      mvwaddch(wmeta->pad.curses_win, all_corners[i].tr.y, all_corners[i].tr.x, '+');
-      mvwaddch(wmeta->pad.curses_win, all_corners[i].bl.y, all_corners[i].bl.x, '+');
-      mvwaddch(wmeta->pad.curses_win, all_corners[i].br.y, all_corners[i].br.x, '+'); }
-    free(all_corners);
-    if (wmeta->pad_offset > 0)
-      draw_scroll_hint(&wmeta->pad, wmeta->pad_offset, wmeta->pad_offset + 1, '<');
-    if (wmeta->pad_offset + wmeta->pad.size.x < getmaxx(wmeta->pad.curses_win) - 1)
-      draw_scroll_hint(&wmeta->pad, wmeta->pad_offset + wmeta->pad.size.x - 1,
-                       getmaxx(wmeta->pad.curses_win) - (wmeta->pad_offset + wmeta->pad.size.x), '>');
-    pnoutrefresh(wmeta->pad.curses_win, 0, wmeta->pad_offset, 0, 0, wmeta->pad.size.y, wmeta->pad.size.x-1); }
-  doupdate(); }
-
-extern void resize_active_win (struct WinMeta * wmeta, struct yx_uint16 size) {
-// Grow or shrink currently active window. Correct its geometry and that of its followers.
-  if (0 != wmeta->active && size.x > 0 && size.y > 0 && size.y < wmeta->pad.size.y) {
-    wmeta->active->frame.size = size;
-    update_wins(wmeta, wmeta->chain_start); } }
-
-extern void cycle_active_win (struct WinMeta * wmeta, char dir) {
-// Cycle active window selection forwards (dir = 'n') or backwards.
-  if (0 != wmeta->active) {
-    if ('n' == dir) {
-      if (wmeta->active->next != 0)
-        wmeta->active = wmeta->active->next;
-      else
-        wmeta->active = wmeta->chain_start; }
-    else {
-      if (wmeta->active->prev != 0)
-        wmeta->active = wmeta->active->prev;
-      else
-        wmeta->active = wmeta->chain_end; } } }
-
-extern void shift_active_win (struct WinMeta * wmeta, char dir) {
-// Move active window forward/backward in window chain. If jumping beyond start/end, move to other chain end.
-  if (0 != wmeta->active && wmeta->chain_start != wmeta->chain_end && (dir == 'f' || dir == 'b')) {
-    struct Win * w_shift = wmeta->active, * w_p, * w_p_next;
-    char wrap = 0;
-    if ((dir == 'f' && w_shift == wmeta->chain_end) || (dir == 'b' && w_shift == wmeta->chain_start))
-      wrap = 1;
-    uint16_t i, i_max;
-    for (i_max = 1, w_p = wmeta->chain_start; w_p != wmeta->chain_end; i_max++)
-      w_p = w_p->next;
-    struct Win ** wins = malloc(i_max * sizeof(struct Win *));
-    for (i = 0, w_p = wmeta->chain_start; i < i_max; i++) {
-      w_p_next = w_p->next;
-      suspend_win(wmeta, w_p);
-      wins[i] = w_p;
-      w_p = w_p_next; }
-    if (wrap)
-      if (dir == 'f') {
-        append_win(wmeta, w_shift);
-        for (i = 0; i < i_max - 1; i++)
-          append_win(wmeta, wins[i]); }
-      else {
-        for (i = 1; i < i_max; i++)
-          append_win(wmeta, wins[i]);
-        append_win(wmeta, w_shift); }
+    {
+        wmeta->chain_start = w->next;
+    }
+    char pad_refitted = 0;
+    if (wmeta->chain_end != w)
+    {
+        w->next->prev = w->prev;
+        if (wmeta->active == w)
+        {
+            wmeta->active = w->next;
+        }
+        uint8_t test = update_wins(wmeta, w->next); /* Positioning of         */
+        if (0 != test)                              /* successor windows may  */
+        {                                           /* be affected / need     */
+            return test;                            /* correction. Note that  */
+        }                                           /* update_wins() already  */
+        pad_refitted = 1;                           /* refits the pad, voiding*/
+    }                                               /* later need for that.   */
+    else
+    {
+        wmeta->chain_end = w->prev;
+        if (wmeta->active == w)
+        {
+            wmeta->active = w->prev;
+        }
+    }
+
+    w->prev = 0;
+    w->next = 0;
+
+    if (0 == pad_refitted)
+    {
+        return refit_pad(wmeta);
+    }
+    return 0;
+}
+
+
+
+extern void reset_pad_offset(struct WinMeta * wmeta, uint16_t new_offset)
+{
+    if (new_offset >= 0
+        && (new_offset < wmeta->pad_offset
+            || new_offset + wmeta->padframe.size.x
+               < getmaxx(wmeta->padframe.curses_win)))
+    {
+        wmeta->pad_offset = new_offset;
+    }
+}
+
+
+
+extern uint8_t resize_active_win(struct WinMeta * wmeta, struct yx_uint16 size)
+{
+    if (0 != wmeta->active
+        && size.x > 0 && size.y > 0
+        && size.y < wmeta->padframe.size.y)
+    {
+        wmeta->active->frame.size = size;
+        return update_wins(wmeta, wmeta->active); /* Positioning of following */
+    }                                             /* windows may be affected. */
+    return 0;
+}
+
+
+
+extern void cycle_active_win(struct WinMeta * wmeta, char dir)
+{
+    if (0 != wmeta->active)
+    {
+        if ('f' == dir)
+        {
+            if (wmeta->active->next != 0)
+            {
+                wmeta->active = wmeta->active->next;
+            }
+            else
+            {
+                wmeta->active = wmeta->chain_start;
+            }
+        }
+        else
+        {
+            if (wmeta->active->prev != 0)
+            {
+                wmeta->active = wmeta->active->prev;
+            }
+            else
+            {
+                wmeta->active = wmeta->chain_end;
+            }
+        }
+    }
+}
+
+
+
+extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir)
+{
+    if (   0 == wmeta->active                        /* No shifting with < 2  */
+        || wmeta->chain_start == wmeta->chain_end)   /* windows visible.      */
+    {
+        return 0;
+    }
+    if ('f' == dir)
+    {
+        shift_win_forward(wmeta);
+    }
     else
-      for (i = 0; i < i_max; i++)
-        if ((dir == 'f' && w_shift == wins[i]) || (dir == 'b' && w_shift == wins[i+1])) {
-          append_win(wmeta, wins[i+1]);
-          append_win(wmeta, wins[i]);
-          i++; }
+    {
+        shift_win_backward(wmeta);
+    }
+    return update_wins(wmeta, wmeta->chain_start);
+}
+
+
+
+extern uint8_t draw_all_wins(struct WinMeta * wmeta)
+{
+    /* Empty everything before filling it a-new. */
+    erase();
+    wnoutrefresh(wmeta->screen);
+    werase(wmeta->padframe.curses_win);
+    if (wmeta->chain_start)
+    {
+
+        /* Draw windows' contents first, then their borders. */
+        draw_wins(wmeta->chain_start);
+        draw_wins_borderlines(wmeta->chain_start, wmeta->active,
+                              wmeta->padframe.curses_win);
+        draw_wins_bordercorners(wmeta->chain_start,wmeta->padframe.curses_win);
+
+        /* Draw virtual screen scroll hints. */
+        if (wmeta->pad_offset > 0)
+        {
+            if (draw_scroll_hint(&wmeta->padframe,
+                                 wmeta->pad_offset, wmeta->pad_offset + 1, '<'))
+            {
+                return 1;
+            }
+        }
+        if (wmeta->pad_offset + wmeta->padframe.size.x
+            < getmaxx(wmeta->padframe.curses_win) - 1)
+        {
+            if (draw_scroll_hint(&wmeta->padframe,
+                                 wmeta->pad_offset + wmeta->padframe.size.x - 1,
+                                 getmaxx(wmeta->padframe.curses_win)
+                                 - (wmeta->pad_offset + wmeta->padframe.size.x),
+                                 '>'))
+            {
+                return 1;
+            }
+        }
+
+        /* Write virtual screen segment to be shown on physical screen into */
+        /* ncurses screen buffer. */
+        pnoutrefresh(wmeta->padframe.curses_win, 0, wmeta->pad_offset, 0, 0,
+                     wmeta->padframe.size.y, wmeta->padframe.size.x-1);
+    }
+
+    /* Only at the end write accumulated changes to the physical screen. */
+    doupdate();
+    return 0;
+}
+
+
+
+extern uint8_t draw_scroll_hint(struct Frame * frame, uint16_t pos,
+                                uint32_t dist, char dir)
+{
+    /* Decide on alignment (vertical/horizontal?), thereby scroll hint text. */
+    char * more = "more";
+    char * unit_cols = "columns";
+    char * unit_rows = "lines";
+    uint16_t dsc_space = frame->size.x;
+    char * unit = unit_rows;
+    if ('<' == dir || '>' == dir)
+    {
+        dsc_space = frame->size.y;
+        unit = unit_cols;
+    }
+    char * scrolldsc = malloc((4 * sizeof(char)) + strlen(more) + strlen(unit)
+                              + 10);                /* 10 = uint32 max strlen */
+    if (NULL == scrolldsc)
+    {
+        return 1;
+    }
+    sprintf(scrolldsc, " %d %s %s ", dist, more, unit);
+
+    /* Decide on offset of the description text inside the scroll hint line. */
+    char offset = 1, q;
+    if (dsc_space > strlen(scrolldsc) + 1)
+    {
+        offset = (dsc_space - strlen(scrolldsc)) / 2;
+    }
+
+    /* Draw scroll hint line as dir symbols bracketing description text. */
+    chtype symbol;
+    for (q = 0; q < dsc_space; q++)
+    {
+        if (q >= offset && q < strlen(scrolldsc) + offset)
+        {
+            symbol = scrolldsc[q - offset] | A_REVERSE;
+        }
+        else
+        {
+            symbol = dir | A_REVERSE;
+        }
+        if ('<' == dir || '>' == dir)
+        {
+            mvwaddch(frame->curses_win, q, pos, symbol);
+        }
         else
-          append_win(wmeta, wins[i]);
-    free(wins);
-    wmeta->active = w_shift; } }
-
-extern void reset_pad_offset(struct WinMeta * wmeta, uint16_t new_offset) {
-// Apply new_offset to windows pad, if it proves to be sane.
-  if (new_offset >= 0 && new_offset + wmeta->pad.size.x < getmaxx(wmeta->pad.curses_win))
-    wmeta->pad_offset = new_offset; }
+        {
+            mvwaddch(frame->curses_win, pos, q, symbol);
+        }
+    }
+
+    free(scrolldsc);
+    return 0;
+}