add ncplane_box_sized() and ncplane_rounded_box_cells()

include/notcurses.h

@@ -187,15 +187,28 @@ int ncplane_vprintf(struct ncplane* n, const char* format, va_list ap);
 int ncplane_hline(struct ncplane* n, const cell* c, int len);
 int ncplane_vline(struct ncplane* n, const cell* c, int len);
 
-// Draw a box with its upper-left corner at the current cursor position, having
-// dimensions |ylen| x |xlen|. The 6 cells provided are used to draw the
+// Draw a box with its upper-left corner at the current cursor position, and its
+// lower-right corner at 'ystop'x'xstop'. The 6 cells provided are used to draw the
 // upper-left, ur, ll, and lr corners, then the horizontal and vertical lines.
 int ncplane_box(struct ncplane* n, const cell* ul, const cell* ur,
                 const cell* ll, const cell* lr, const cell* hline,
-                const cell* vline, int ylen, int xlen);
+                const cell* vline, int ystop, int xstop);
 
-// Erase all content in the ncplane, resetting all attributes to normal, all
-// colors to -1, and all cells to undrawn.
+// Draw a box with its upper-left corner at the current cursor position, having
+// dimensions 'ylen'x'xlen'. See ncplane_box() for more information. The
+// minimum box size is 2x2, and it cannot be drawn off-screen.
+static inline int
+ncplane_box_sized(struct ncplane* n, const cell* ul, const cell* ur,
+                  const cell* ll, const cell* lr, const cell* hline,
+                  const cell* vline, int ylen, int xlen){
+  int y, x;
+  ncplane_cursor_yx(n, &y, &x);
+  return ncplane_box(n, ul, ur, ll, lr, hline, vline, y + ylen - 1, x + xlen - 1);
+}
+
+// Erase every cell in the ncplane, resetting all attributes to normal, all
+// colors to the default color, and all cells to undrawn. All cells associated
+// with this ncplane is invalidated, and must not be used after the call.
 void ncplane_erase(struct ncplane* n);
 
 // Set the current fore/background color using RGB specifications. If the
@@ -356,6 +369,12 @@ cell_wide_p(const cell* c){
   return (c->channels & CELL_WIDEASIAN_MASK);
 }
 
+// load up six cells with the EGCs necessary to draw a light, rounded box.
+// returns 0 on success, -1 on error. on error, any cells this function might
+// have loaded before the error are cell_release()d.
+int ncplane_rounded_box_cells(struct ncplane* n, cell* ul, cell* ur, cell* ll,
+                              cell* lr, cell* hl, cell* vl);
+
 // multimedia functionality
 int notcurses_visual_open(struct notcurses* nc, const char* filename);
 

src/lib/notcurses.c

@@ -822,21 +822,24 @@ int ncplane_vline(ncplane* n, const cell* c, int len){
 
 int ncplane_box(ncplane* n, const cell* ul, const cell* ur,
                 const cell* ll, const cell* lr, const cell* hl,
-                const cell* vl, int ylen, int xlen){
-  if(xlen < 2 || ylen < 2){
-    return -1;
-  }
+                const cell* vl, int ystop, int xstop){
   int yoff, xoff, ymax, xmax;
   ncplane_cursor_yx(n, &yoff, &xoff);
+  if(ystop < yoff + 1){
+    return -1;
+  }
+  if(xstop < xoff + 1){
+    return -1;
+  }
   ncplane_dimyx(n, &ymax, &xmax);
-  if(xmax - xoff < xlen || ymax - yoff < ylen){
+  if(xstop >= xmax || ystop >= ymax){
     return -1;
   }
   if(ncplane_putc(n, ul) < 0){
     return -1;
   }
-  if(xlen > 2){
-    if(ncplane_hline(n, hl, xlen - 2) < 0){
+  if(xstop - xoff >= 2){
+    if(ncplane_hline(n, hl, xstop - xoff - 1) < 0){
       return -1;
     }
   }
@@ -844,14 +847,14 @@ int ncplane_box(ncplane* n, const cell* ul, const cell* ur,
     return -1;
   }
   ++yoff;
-  while(yoff < ylen - 1){
+  while(yoff < ystop){
     if(ncplane_cursor_move_yx(n, yoff, xoff)){
       return -1;
     }
     if(ncplane_putc(n, vl) < 0){
       return -1;
     }
-    if(ncplane_cursor_move_yx(n, yoff, xoff + xlen - 1)){
+    if(ncplane_cursor_move_yx(n, yoff, xstop)){
       return -1;
     }
     if(ncplane_putc(n, vl) < 0){
@@ -865,8 +868,8 @@ int ncplane_box(ncplane* n, const cell* ul, const cell* ur,
   if(ncplane_putc(n, ll) < 0){
     return -1;
   }
-  if(xlen > 2){
-    if(ncplane_hline(n, hl, xlen - 2) < 0){
+  if(xstop - xoff >= 2){
+    if(ncplane_hline(n, hl, xstop - xoff - 1) < 0){
       return -1;
     }
   }
@@ -881,3 +884,26 @@ void ncplane_erase(ncplane* n){
   egcpool_dump(&n->pool);
   egcpool_init(&n->pool);
 }
+
+int ncplane_rounded_box_cells(ncplane* n, cell* ul, cell* ur, cell* ll,
+                              cell* lr, cell* hl, cell* vl){
+  if(cell_load(n, ul, "╭") > 0){
+    if(cell_load(n, ur, "╮") > 0){
+      if(cell_load(n, ll, "╰") > 0){
+        if(cell_load(n, lr, "╯") > 0){
+          if(cell_load(n, hl, "─") > 0){
+            if(cell_load(n, vl, "│") > 0){
+              return 0;
+            }
+            cell_release(n, hl);
+          }
+          cell_release(n, lr);
+        }
+        cell_release(n, ll);
+      }
+      cell_release(n, ur);
+    }
+    cell_release(n, ul);
+  }
+  return -1;
+}