recenter post-rotation in normal demo #617

include/notcurses/notcurses.h

@@ -1232,6 +1232,9 @@ API char* ncplane_contents(const struct ncplane* nc, int begy, int begx,
 API void* ncplane_set_userptr(struct ncplane* n, void* opaque);
 API void* ncplane_userptr(struct ncplane* n);
 
+API void ncplane_center_abs(const struct ncplane* n, int* RESTRICT y,
+                            int* RESTRICT x);
+
 // Return the column at which 'c' cols ought start in order to be aligned
 // according to 'align' within ncplane 'n'. Returns INT_MAX on invalid 'align'.
 // Undefined behavior on negative 'c'.

src/demo/normal.c

@@ -96,16 +96,30 @@ int normal_demo(struct notcurses* nc){
   cell_release(nstd, &c);
   for(int i = 0 ; i < 16 ; ++i){
     demo_nanosleep(nc, &scaled);
+    int centy, centx;
+    ncplane_center_abs(n, &centy, &centx);
     if(ncplane_rotate_cw(n)){
       goto err;
     }
+    int cent2y, cent2x;
+    int absy, absx;
+    ncplane_center_abs(n, &cent2y, &cent2x);
+    ncplane_yx(n, &absy, &absx);
+    ncplane_move_yx(n, absy + centy - cent2y, absx + centx - cent2x);
     DEMO_RENDER(nc);
   }
   for(int i = 0 ; i < 16 ; ++i){
     demo_nanosleep(nc, &scaled);
+    int centy, centx;
+    ncplane_center_abs(n, &centy, &centx);
     if(ncplane_rotate_ccw(n)){
       goto err;
     }
+    int cent2y, cent2x;
+    int absy, absx;
+    ncplane_center_abs(n, &cent2y, &cent2x);
+    ncplane_yx(n, &absy, &absx);
+    ncplane_move_yx(n, absy + centy - cent2y, absx + centx - cent2x);
     DEMO_RENDER(nc);
   }
   ncplane_destroy(n);

src/lib/fill.c

@@ -563,11 +563,6 @@ int ncplane_rotate_cw(ncplane* n){
   }
   int ret = rotate_merge(n, newp);
   ret |= ncplane_destroy(newp);
-  int cent2y, cent2x;
-  int absy, absx;
-  ncplane_center_abs(n, &cent2y, &cent2x);
-  ncplane_yx(n, &absy, &absx);
-  ncplane_move_yx(n, absy + centy - cent2y, absx + centx - cent2x);
   return ret;
 }
 
@@ -578,8 +573,6 @@ int ncplane_rotate_ccw(ncplane* n){
   }
   int dimy, dimx, targdimy, targdimx;
   ncplane_dim_yx(n, &dimy, &dimx);
-  int centy, centx;
-  ncplane_center_abs(n, &centy, &centx);
   ncplane_dim_yx(newp, &targdimy, &targdimx);
   int x = dimx - 2, y;
   // Each row of the target plane is taken from a column of the source plane.
@@ -597,11 +590,6 @@ int ncplane_rotate_ccw(ncplane* n){
   }
   int ret = rotate_merge(n, newp);
   ret |= ncplane_destroy(newp);
-  int cent2y, cent2x;
-  int absy, absx;
-  ncplane_center_abs(n, &cent2y, &cent2x);
-  ncplane_yx(n, &absy, &absx);
-  ncplane_move_yx(n, absy + centy - cent2y, absx + centx - cent2x);
   return ret;
 }
 

src/lib/internal.h

@@ -648,21 +648,6 @@ ncplane_center(const ncplane* n, int* RESTRICT y, int* RESTRICT x){
   center_box(y, x);
 }
 
-// find the center coordinate of a plane, preferring the top/left in the
-// case of an even number of rows/columns (in such a case, there will be one
-// more cell to the bottom/right of the center than the top/left). the
-// center is then modified relative to the plane's origin.
-static inline void
-ncplane_center_abs(const ncplane* n, int* RESTRICT y, int* RESTRICT x){
-  ncplane_center(n, y, x);
-  if(y){
-    *y += n->absy;
-  }
-  if(x){
-    *x += n->absx;
-  }
-}
-
 int ncvisual_bounding_box(const struct ncvisual* ncv, int* leny, int* lenx,
                           int* offy, int* offx);
 

src/lib/notcurses.c

@@ -2003,3 +2003,17 @@ int cells_rounded_box(struct ncplane* n, uint32_t attr, uint64_t channels,
   }
   return cells_ascii_box(n, attr, channels, ul, ur, ll, lr, hl, vl);
 }
+
+// find the center coordinate of a plane, preferring the top/left in the
+// case of an even number of rows/columns (in such a case, there will be one
+// more cell to the bottom/right of the center than the top/left). the
+// center is then modified relative to the plane's origin.
+void ncplane_center_abs(const ncplane* n, int* RESTRICT y, int* RESTRICT x){
+  ncplane_center(n, y, x);
+  if(y){
+    *y += n->absy;
+  }
+  if(x){
+    *x += n->absx;
+  }
+}