[bitmaps] clear out ncvisual link on hide

src/lib/internal.h

@@ -69,7 +69,10 @@ typedef struct sprixel {
   char* glyph;          // glyph; can be quite large
   int glyphlen;         // length of the glyph in bytes
   uint32_t id;          // embedded into glusters field of nccell, 24 bits
+  // both the plane and visual can die before the sprixel does. they are
+  // responsible in such a case for NULLing out this link themselves.
   struct ncplane* n;    // associated ncplane
+  struct ncvisual* ncv; // associated ncvisual
   sprixel_e invalidated;// sprixel invalidation state
   struct sprixel* next;
   int y, x;
@@ -811,8 +814,8 @@ int sprite_draw(const notcurses* n, const ncpile *p, sprixel* s, FILE* out);
 int kitty_draw(const notcurses* n, const ncpile *p, sprixel* s, FILE* out);
 int sixel_draw(const notcurses* n, const ncpile *p, sprixel* s, FILE* out);
 // dimy and dimx are cell geometry, not pixel. takes ownership of s on success.
-sprixel* sprixel_alloc(ncplane* n, int dimy, int dimx);
-sprixel* sprixel_recycle(ncplane* n);
+sprixel* sprixel_alloc(ncplane* n, struct ncvisual* ncv, int dimy, int dimx);
+sprixel* sprixel_recycle(ncplane* n, struct ncvisual* ncv);
 int sprixel_load(sprixel* spx, char* s, int bytes, int placey, int placex,
                  int pixy, int pixx, int parse_start);
 int sprite_wipe_cell(const notcurses* nc, sprixel* s, int y, int x);

src/lib/sprite.c

@@ -1,22 +1,29 @@
 #include "internal.h"
+#include "visual-details.h"
 
 // FIXME needs be atomic
 static uint32_t sprixelid_nonce;
 
 void sprixel_free(sprixel* s){
   if(s){
+    if(s->n){
+      s->n->sprite = NULL;
+    }
+    if(s->ncv){
+      s->ncv->spx = NULL;
+    }
     free(s->glyph);
     free(s);
   }
 }
 
-sprixel* sprixel_recycle(ncplane* n){
+sprixel* sprixel_recycle(ncplane* n, ncvisual* ncv){
   const notcurses* nc = ncplane_notcurses(n);
   if(nc->tcache.pixel_destroy == sprite_kitty_annihilate){
     int dimy = n->sprite->dimy;
     int dimx = n->sprite->dimx;
     sprixel_hide(n->sprite);
-    return sprixel_alloc(n, dimy, dimx);
+    return sprixel_alloc(n, ncv, dimy, dimx);
   }
   return n->sprite;
 }
@@ -40,6 +47,8 @@ void sprixel_hide(sprixel* s){
     s->invalidated = SPRIXEL_HIDE;
     s->movedfromy = ncplane_abs_y(s->n);
     s->movedfromx = ncplane_abs_x(s->n);
+    s->ncv->spx = NULL;
+    s->ncv = NULL;
     s->n->sprite = NULL;
     s->n = NULL;
   }
@@ -60,11 +69,12 @@ sprixel* sprixel_by_id(const notcurses* nc, uint32_t id){
   return NULL;
 }
 
-sprixel* sprixel_alloc(ncplane* n, int dimy, int dimx){
+sprixel* sprixel_alloc(ncplane* n, ncvisual* ncv, int dimy, int dimx){
   sprixel* ret = malloc(sizeof(sprixel));
   if(ret){
     memset(ret, 0, sizeof(*ret));
     ret->n = n;
+    ret->ncv = ncv;
     ret->dimy = dimy;
     ret->dimx = dimx;
     ret->id = ++sprixelid_nonce;

src/lib/visual.c

@@ -605,11 +605,11 @@ ncplane* ncvisual_render_pixels(notcurses* nc, ncvisual* ncv, const struct blits
   if(ncv->spx == NULL){
     int cols = dispcols / bargs.u.pixel.celldimx + !!(dispcols % bargs.u.pixel.celldimx);
     int rows = disprows / bargs.u.pixel.celldimy + !!(disprows % bargs.u.pixel.celldimy);
-    if((ncv->spx = sprixel_alloc(n, rows, cols)) == NULL){
+    if((ncv->spx = sprixel_alloc(n, ncv, rows, cols)) == NULL){
       goto err;
     }
   }else{
-    ncv->spx = sprixel_recycle(n);
+    ncv->spx = sprixel_recycle(n, ncv);
   }
   bargs.u.pixel.spx = ncv->spx;
   if(ncvisual_blit(ncv, disprows, dispcols, n, bset, disprows, dispcols, &bargs)){