ncplane_at_yx(): const ncplane argument

CHANGELOG.md

@@ -15,6 +15,7 @@ rearrangements of Notcurses.
     `ncplane` to an `ncvisual`. The source plane may contain only spaces,
     half blocks, and full blocks. This builds atop the new function
     `ncplane_rgba()`, which makes an RGBA flat array from an `ncplane`.
+  * The `ncplane` argument to `ncplane_at_yx()` is now `const`.
 
 * 1.3.3 (2020-04-26)
   * The `ncdplot` type has been added for plots based on `double`s rather than

USAGE.md

@@ -718,7 +718,7 @@ int ncplane_at_cursor_cell(struct ncplane* n, cell* c);
 // Retrieve the current contents of the specified cell. The EGC is returned, or
 // NULL on error. This EGC must be free()d by the caller. The attrword and
 // channels are written to 'attrword' and 'channels', respectively.
-char* ncplane_at_yx(struct ncplane* n, int y, int x,
+char* ncplane_at_yx(const struct ncplane* n, int y, int x,
                     uint32_t* attrword, uint64_t* channels);
 
 // Retrieve the current contents of the specified cell into 'c'. This cell is

doc/man/man3/notcurses_plane.3.md

@@ -46,7 +46,7 @@ notcurses_plane - operations on ncplanes
 
 **int ncplane_at_cursor_cell(struct ncplane* n, cell* c);**
 
-**char* ncplane_at_yx(struct ncplane* n, int y, int x, uint32_t* attrword, uint64_t* channels);**
+**char* ncplane_at_yx(const struct ncplane* n, int y, int x, uint32_t* attrword, uint64_t* channels);**
 
 **int ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c);**
 

include/notcurses/notcurses.h

@@ -675,7 +675,8 @@ cell_strdup(const struct ncplane* n, const cell* c){
 
 // Extract the three elements of a cell.
 static inline char*
-cell_extract(const struct ncplane* n, const cell* c, uint32_t* attrword, uint64_t* channels){
+cell_extract(const struct ncplane* n, const cell* c,
+             uint32_t* attrword, uint64_t* channels){
   if(attrword){
     *attrword = c->attrword;
   }
@@ -1166,7 +1167,7 @@ ncplane_at_cursor_cell(struct ncplane* n, cell* c){
 // Retrieve the current contents of the specified cell. The EGC is returned, or
 // NULL on error. This EGC must be free()d by the caller. The attrword and
 // channels are written to 'attrword' and 'channels', respectively.
-API char* ncplane_at_yx(struct ncplane* n, int y, int x,
+API char* ncplane_at_yx(const struct ncplane* n, int y, int x,
                         uint32_t* attrword, uint64_t* channels);
 
 // Retrieve the current contents of the specified cell into 'c'. This cell is

python/src/notcurses/build_notcurses.py

@@ -139,7 +139,7 @@ struct ncplane* ncplane_below(struct ncplane* n);
 char* notcurses_at_yx(struct notcurses* nc, int yoff, int xoff, uint32_t* attrword, uint64_t* channels);
 char* ncplane_at_cursor(struct ncplane* n, uint32_t* attrword, uint64_t* channels);
 int ncplane_at_cursor_cell(struct ncplane* n, cell* c);
-char* ncplane_at_yx(struct ncplane* n, int y, int x, uint32_t* attrword, uint64_t* channels);
+char* ncplane_at_yx(const struct ncplane* n, int y, int x, uint32_t* attrword, uint64_t* channels);
 int ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c);
 uint32_t* ncplane_rgba(const struct ncplane* nc, int begy, int begx, int leny, int lenx);
 void* ncplane_set_userptr(struct ncplane* n, void* opaque);