alignment: add NCALIGN_UNALIGNED, preserve align type #364

include/notcurses/notcurses.h

@@ -68,6 +68,7 @@ typedef enum {
 
 // Alignment within a plane or terminal. Left/right-justified, or centered.
 typedef enum {
+  NCALIGN_UNALIGNED,
   NCALIGN_LEFT,
   NCALIGN_CENTER,
   NCALIGN_RIGHT,
@@ -1293,7 +1294,10 @@ notcurses_align(int availcols, ncalign_e align, int cols){
   if(align == NCALIGN_CENTER){
     return (availcols - cols) / 2;
   }
-  return availcols - cols; // NCALIGN_RIGHT
+  if(align == NCALIGN_RIGHT){
+    return availcols - cols;
+  }
+  return -INT_MAX;
 }
 
 // Return the column at which 'c' cols ought start in order to be aligned

src/lib/internal.h

@@ -85,6 +85,7 @@ typedef struct ncplane {
   cell basecell;         // cell written anywhere that fb[i].gcluster == 0
   struct notcurses* nc;  // notcurses object of which we are a part
   char* name;            // used only for debugging
+  ncalign_e align;       // relative to parent plane, for automatic realignment
   uint16_t stylemask;    // same deal as in a cell
   bool scrolling;        // is scrolling enabled? always disabled by default
 } ncplane;

src/lib/notcurses.c

@@ -320,9 +320,11 @@ ncplane* ncplane_new_internal(notcurses* nc, ncplane* n, const ncplane_options*
   p->logrow = 0;
   p->blist = NULL;
   p->name = nopts->name ? strdup(nopts->name) : NULL;
+  p->align = NCALIGN_UNALIGNED;
   if( (p->boundto = n) ){
     if(nopts->flags & NCPLANE_OPTION_HORALIGNED){
       p->absx = ncplane_align(n, nopts->horiz.align, nopts->cols);
+      p->align = nopts->horiz.align;
     }else{
       p->absx = nopts->horiz.x;
     }
@@ -2007,6 +2009,20 @@ const ncplane* ncplane_parent_const(const ncplane* n){
   return n->boundto;
 }
 
+int ncplane_resize_realign(ncplane* n){
+  const ncplane* parent = ncplane_parent_const(n);
+  if(parent == n){ // somehow got stdplane, should never get here
+    logerror(ncplane_notcurses(n), "Passed the standard plane");
+    return -1;
+  }
+  if(n->align == NCALIGN_UNALIGNED){
+    logerror(ncplane_notcurses(n), "Passed a non-aligned plane");
+    return -1;
+  }
+  int xpos = ncplane_align(parent, n->align, ncplane_dim_x(n));
+  return ncplane_move_yx(n, ncplane_y(n), xpos);
+}
+
 ncplane* ncplane_reparent(ncplane* n, ncplane* newparent){
   if(n == n->nc->stdplane){
     return NULL; // can't reparent standard plane