attempt to lessen screentearing

TODO.md

@@ -12,3 +12,9 @@ then fork and exec shfx as child (+ close ptmx), then close pts as parent.
 - [ ] cursetree shits itself if width/height are 0 on bifurcation
 
 - [ ] ensure NDEBUG is set for preprocessor to avoid <assert.h> statements if not debugging
+
+
+- [ ] resize_node() is quite wasteful and results could definitely be cached for the next resize_node() call
+
+- I think this should help!
+      https://tldp.org/HOWTO/NCURSES-Programming-HOWTO/windows.html#OTHERBORDERFUNCS

cli/main.c

@@ -23,43 +23,44 @@ int main(int argc, char **argv) {
   init_pair(5, COLOR_BLACK, COLOR_YELLOW);
 
   struct ct_node *const child1 = new_node(bounds_none(), tree->root);
-  struct ct_node *const child2 = new_node(bounds_none(), tree->root);
-  struct ct_node *const child3 = new_node(bounds_none(), tree->root);
-  struct ct_node *const child4 = new_node(bounds_none(), tree->root);
-  struct ct_node *const child5 = new_node(bounds_none(), tree->root);
+  // struct ct_node *const child2 = new_node(bounds_none(), tree->root);
+  // struct ct_node *const child3 = new_node(bounds_none(), tree->root);
+  // struct ct_node *const child4 = new_node(bounds_none(), tree->root);
+  // struct ct_node *const child5 = new_node(bounds_none(), tree->root);
   append_child_node(tree->root, child1);
-  append_child_node(tree->root, child2);
-  append_child_node(tree->root, child3);
-  append_child_node(tree->root, child4);
-  append_child_node(tree->root, child5);
+  // append_child_node(tree->root, child2);
+  // append_child_node(tree->root, child3);
+  // append_child_node(tree->root, child4);
+  // append_child_node(tree->root, child5);
 
   wbkgd(child1->surface->win, COLOR_PAIR(1));
-  wbkgd(child2->surface->win, COLOR_PAIR(2));
-  wbkgd(child3->surface->win, COLOR_PAIR(3));
-  wbkgd(child4->surface->win, COLOR_PAIR(4));
-  wbkgd(child5->surface->win, COLOR_PAIR(5));
+  // wbkgd(child2->surface->win, COLOR_PAIR(2));
+  // wbkgd(child3->surface->win, COLOR_PAIR(3));
+  // wbkgd(child4->surface->win, COLOR_PAIR(4));
+  // wbkgd(child5->surface->win, COLOR_PAIR(5));
 
-  child3->axis = AXIS_Y;
-  struct ct_node *const child3_1 = new_node(bounds_none(), child3);
-  struct ct_node *const child3_2 = new_node(bounds_none(), child3);
-  append_child_node(child3, child3_1);
-  append_child_node(child3, child3_2);
-  wbkgd(child3_1->surface->win, COLOR_PAIR(1));
-  wbkgd(child3_2->surface->win, COLOR_PAIR(5));
+  // child3->axis = AXIS_Y;
+  // struct ct_node *const child3_1 = new_node(bounds_none(), child3);
+  // struct ct_node *const child3_2 = new_node(bounds_none(), child3);
+  // append_child_node(child3, child3_1);
+  // append_child_node(child3, child3_2);
+  // wbkgd(child3_1->surface->win, COLOR_PAIR(1));
+  // wbkgd(child3_2->surface->win, COLOR_PAIR(5));
 
   while (1) {
-    nprintsfdims(child2, 0, "R", tree->root);
-    nprintsfdims(child2, 1, "1", child1);
-    nprintsfdims(child2, 2, "2", child2);
-    nprintsfdims(child2, 3, "3", child3);
-    nprintsfdims(child2, 4, "4", child4);
-    nprintsfdims(child2, 5, "5", child5);
-    
-    nprintsfdims(child2, 7, "3_1", child3_1);
-    nprintsfdims(child2, 8, "3_2", child3_2);
-    
-
     ct_update(tree);
+    
+    // nprintsfdims(child2, 0, "R", tree->root);
+    // nprintsfdims(child2, 1, "1", child1);
+    // nprintsfdims(child2, 2, "2", child2);
+    // nprintsfdims(child2, 3, "3", child3);
+    // nprintsfdims(child2, 4, "4", child4);
+    // nprintsfdims(child2, 5, "5", child5);
+    
+    // nprintsfdims(child2, 7, "3_1", child3_1);
+    // nprintsfdims(child2, 8, "3_2", child3_2);
+
+    ct_process(tree);
   }
 
   destroy_tree(tree);

cursetree/cursetree.c

@@ -1,11 +1,45 @@
+#include <signal.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "_ncurses.h"
 #include "ncrswrap.h"
+#include "ncurses.h"
 #include "node.h"
 #include "tree.h"
 
+volatile sig_atomic_t got_winch = 0;
+
+void handle_SIGWINCH(int sig) {
+  // endwin();
+  // Needs to be called after an endwin() so ncurses will initialize
+  // itself with the new terminal dimensions.
+  got_winch = 1;
+}
+
+/*
+ * If ncurses is configured to supply its own SIGWINCH handler,
+ *   - on receipt of a SIGWINCH, the handler sets a flag
+ *   - which is tested in wgetch(3X), doupdate(3X) and restartterm(3X),
+ *   - in turn, calling the resizeterm function,
+ *   - which ungetch's a KEY_RESIZE which will be read on the next call to
+ * wgetch. REF: `man resizeterm(3x)`
+ */
+static void bind_SIGWINCH(void) {
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sa.sa_handler = handle_SIGWINCH;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = SA_RESTART; /* Restart functions if
+                               interrupted by handler */
+  if (sigaction(SIGWINCH, &sa, NULL) == -1) {
+    perror("bind_SIGWINCH");
+    exit(2);
+  }
+}
+
 int ct_init(struct ct_tree **const tree) {
+  // bind_SIGWINCH();
   /* Initialise NCurses Library & Root Node */
   init_ncurses();
   init_tree(tree);
@@ -34,10 +68,13 @@ static int __update_rec(struct ct_node *const node) {
      */
     dims = IS_ROOT_NODE(node) ? termdims() : dup_dims(node->surface->dims);
     resize_node(node, dims);
+    node->flags &= ~NFLAG_RESIZE;
     result = 1;
   }
   if (node->surface->updatereq) {
-    sfflush(node->surface);
+    // TODO: is this necessary or does mvresize_win do this for us?
+    wnoutrefresh(node->surface->win);
+    node->surface->updatereq = 0;
   }
 
   for (int i = 0; i < node->cindex; i++) {
@@ -47,7 +84,17 @@ static int __update_rec(struct ct_node *const node) {
 }
 
 void ct_update(struct ct_tree *const tree) {
+  // WARNING: update_rec does not flush the screen, wgetch will do that for us
+  if (__update_rec(tree->root)) {
+    doupdate();
+    // redrawwin(curscr);
+    // wrefresh(curscr);
+  }
+}
+
+void ct_process(struct ct_tree *const tree) {
   const int key = wgetch(curscr);
+  // int key = -1;
 
   /* ncurses binds a SIGWINCH handler if SIGWINCH has SIG_DFL disposition
    * when initscr(3x) is called. This handler emits KEY_RESIZE (decimal 410) to
@@ -58,8 +105,9 @@ void ct_update(struct ct_tree *const tree) {
     // wclear(tree->root->surface->win);
     // mvwprintw(tree->root->surface->win, 0, 0, "    \r-1\n");
     // wrefresh(tree->root->surface->win);
-    return;
+    break;
   case KEY_RESIZE:
+    // got_winch = 1;
     tree->root->flags |= NFLAG_RESIZE;
     break;
   default:
@@ -69,7 +117,12 @@ void ct_update(struct ct_tree *const tree) {
     break;
   }
 
-  if (__update_rec(tree->root)) {
-    ct_redraw();
-  }
+  // if (got_winch == 1) {
+  //   tree->root->flags |= NFLAG_RESIZE;
+  //   got_winch = 0;
+  // }
+
+  // if (__update_rec(tree->root)) {
+  //   ct_redraw();
+  // }
 }

cursetree/cursetree.h

@@ -6,5 +6,6 @@
 /* === External Interface === */
 int ct_init(struct ct_tree **const tree);
 void ct_update(struct ct_tree *const tree);
+void ct_process(struct ct_tree *const tree);
 
 #endif /* CURSETREE_CURSETREE_H */