[paint] why must we constify ourselves, every day

include/notcurses/notcurses.h

@@ -1944,7 +1944,7 @@ API int ncplane_stain(struct ncplane* n, int ystop, int xstop, uint64_t ul,
 
 // If 'src' does not intersect with 'dst', 'dst' will not be changed, but it is
 // not an error. If 'dst' is NULL, the operation will target the standard plane.
-API int ncplane_mergedown_simple(struct ncplane* RESTRICT src,
+API int ncplane_mergedown_simple(const struct ncplane* RESTRICT src,
                                  struct ncplane* RESTRICT dst);
 
 // Merge the ncplane 'src' down onto the ncplane 'dst'. This is most rigorously
@@ -1956,7 +1956,7 @@ API int ncplane_mergedown_simple(struct ncplane* RESTRICT src,
 // is an error to define a target origin such that the projected subregion is
 // not entirely contained within 'dst'.  Behavior is undefined if 'src' and
 // 'dst' are equivalent. 'dst' is modified, but 'src' remains unchanged.
-API int ncplane_mergedown(struct ncplane* RESTRICT src,
+API int ncplane_mergedown(const struct ncplane* RESTRICT src,
                           struct ncplane* RESTRICT dst,
                           int begsrcy, int begsrcx, int leny, int lenx,
                           int dsty, int dstx);

src/lib/internal.h

@@ -778,7 +778,7 @@ int sprite_kitty_init(int fd);
 int sprite_sixel_init(int fd);
 int sprite_init(const notcurses* nc);
 void sprixel_invalidate(sprixel* s);
-sprixel* sprixel_by_id(notcurses* nc, uint32_t id);
+sprixel* sprixel_by_id(const notcurses* nc, uint32_t id);
 
 static inline void
 pool_release(egcpool* pool, nccell* c){

src/lib/render.c

@@ -246,7 +246,7 @@ highcontrast(uint32_t bchannel){
 // rendered.
 //
 static void
-paint(ncplane* p, struct crender* rvec, int dstleny, int dstlenx,
+paint(const ncplane* p, struct crender* rvec, int dstleny, int dstlenx,
       int dstabsy, int dstabsx){
   int y, x, dimy, dimx, offy, offx;
   ncplane_dim_yx(p, &dimy, &dimx);
@@ -299,7 +299,7 @@ paint(ncplane* p, struct crender* rvec, int dstleny, int dstlenx,
           // if we are a bitmap, and above a cell that has changed (and
           // will thus be printed), we'll need redraw the sprixel.
           if(rvec->sprixel == NULL){
-            rvec->sprixel = sprixel_by_id(ncplane_notcurses(p), cell_sprixel_id(vis));
+            rvec->sprixel = sprixel_by_id(ncplane_notcurses_const(p), cell_sprixel_id(vis));
           }
         }
         continue;
@@ -514,27 +514,27 @@ postpaint(nccell* lastframe, int dimy, int dimx, struct crender* rvec, egcpool*
 
 // merging one plane down onto another is basically just performing a render
 // using only these two planes, with the result written to the lower plane.
-int ncplane_mergedown(ncplane* restrict src, ncplane* restrict dst,
+int ncplane_mergedown(const ncplane* restrict src, ncplane* restrict dst,
                       int begsrcy, int begsrcx, int leny, int lenx,
                       int dsty, int dstx){
 //fprintf(stderr, "Merging down %d/%d @ %d/%d to %d/%d\n", leny, lenx, begsrcy, begsrcx, dsty, dstx);
   if(dsty >= dst->leny || dstx >= dst->lenx){
-    logerror(ncplane_notcurses(dst), "Dest origin %d/%d ≥ dest dimensions %d/%d\n",
+    logerror(ncplane_notcurses_const(dst), "Dest origin %d/%d ≥ dest dimensions %d/%d\n",
              dsty, dstx, dst->leny, dst->lenx);
     return -1;
   }
   if(dst->leny - leny < dsty || dst->lenx - lenx < dstx){
-    logerror(ncplane_notcurses(dst), "Dest len %d/%d ≥ dest dimensions %d/%d\n",
+    logerror(ncplane_notcurses_const(dst), "Dest len %d/%d ≥ dest dimensions %d/%d\n",
              leny, lenx, dst->leny, dst->lenx);
     return -1;
   }
   if(begsrcy >= src->leny || begsrcx >= src->lenx){
-    logerror(ncplane_notcurses(dst), "Source origin %d/%d ≥ source dimensions %d/%d\n",
+    logerror(ncplane_notcurses_const(dst), "Source origin %d/%d ≥ source dimensions %d/%d\n",
              begsrcy, begsrcx, src->leny, src->lenx);
     return -1;
   }
   if(src->leny - leny < begsrcy || src->lenx - lenx < begsrcx){
-    logerror(ncplane_notcurses(dst), "Source len %d/%d ≥ source dimensions %d/%d\n",
+    logerror(ncplane_notcurses_const(dst), "Source len %d/%d ≥ source dimensions %d/%d\n",
              leny, lenx, src->leny, src->lenx);
     return -1;
   }
@@ -543,7 +543,7 @@ int ncplane_mergedown(ncplane* restrict src, ncplane* restrict dst,
   const size_t crenderlen = sizeof(struct crender) * totalcells;
   struct crender* rvec = malloc(crenderlen);
   if(!rendfb || !rvec){
-    logerror(ncplane_notcurses(dst), "Error allocating render state for %dx%d\n", leny, lenx);
+    logerror(ncplane_notcurses_const(dst), "Error allocating render state for %dx%d\n", leny, lenx);
     free(rendfb);
     free(rvec);
     return -1;
@@ -560,7 +560,7 @@ int ncplane_mergedown(ncplane* restrict src, ncplane* restrict dst,
   return 0;
 }
 
-int ncplane_mergedown_simple(ncplane* restrict src, ncplane* restrict dst){
+int ncplane_mergedown_simple(const ncplane* restrict src, ncplane* restrict dst){
   const notcurses* nc = ncplane_notcurses_const(src);
   if(dst == NULL){
     dst = nc->stdplane;

src/lib/sprite.c

@@ -19,7 +19,7 @@ void sprixel_invalidate(sprixel* s){
   }
 }
 
-sprixel* sprixel_by_id(notcurses* nc, uint32_t id){
+sprixel* sprixel_by_id(const notcurses* nc, uint32_t id){
   for(sprixel* cur = nc->sprixelcache ; cur ; cur = cur->next){
     if(cur->id == id){
       return cur;