ncdirectf_render: make ncvisual_options const, thanks @joseluis #1738

doc/man/man3/notcurses_direct.3.md

@@ -116,7 +116,7 @@ typedef struct ncvgeom {
 
 **void ncdirectf_free(struct ncdirectf* ***frame***);**
 
-**ncdirectv* ncdirectf_render(struct ncdirect* ***n***, struct ncdirectf* ***frame***, struct ncvisual_options ***vopts***);**
+**ncdirectv* ncdirectf_render(struct ncdirect* ***n***, struct ncdirectf* ***frame***, const struct ncvisual_options ***vopts***);**
 
 **int ncdirectf_geom(struct ncdirect* ***n***, struct ncdirectf* ***frame***, ncblitter_e* ***blitter***, ncscale_e ***scale***, int ***maxy***, int ***maxx***, ncvgeom* ***geom***);**
 

include/notcurses/direct.h

@@ -389,7 +389,7 @@ API void ncdirectf_free(ncdirectf* frame);
 // loaded. A loaded frame may be rendered in different ways before it is
 // destroyed.
 API ALLOC ncdirectv* ncdirectf_render(struct ncdirect* n, ncdirectf* frame,
-                                      struct ncvisual_options* vopts)
+                                      const struct ncvisual_options* vopts)
   __attribute__ ((nonnull (1, 2)));
 
 // Having loaded the frame 'frame', get the geometry of a potential render.

src/lib/direct.c

@@ -545,7 +545,8 @@ int ncdirect_raster_frame(ncdirect* n, ncdirectv* ncdv, ncalign_e align){
 }
 
 static ncdirectv*
-ncdirect_render_visual(ncdirect* n, ncvisual* ncv, struct ncvisual_options* vopts){
+ncdirect_render_visual(ncdirect* n, ncvisual* ncv,
+                       const struct ncvisual_options* vopts){
   struct ncvisual_options defvopts = {};
   if(!vopts){
     vopts = &defvopts;
@@ -1313,7 +1314,7 @@ void ncdirectf_free(ncdirectf* frame){
   ncvisual_destroy(frame);
 }
 
-ncdirectv* ncdirectf_render(ncdirect* n, ncdirectf* frame, struct ncvisual_options* vopts){
+ncdirectv* ncdirectf_render(ncdirect* n, ncdirectf* frame, const struct ncvisual_options* vopts){
   return ncdirect_render_visual(n, frame, vopts);
 }