From 021fc052fc14b22cbe5cbad221d5d72bf3b41e49 Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Thu, 1 Apr 2021 22:03:32 -0400
Subject: [PATCH] [render] end kitty flicker #1493

---
 src/lib/internal.h  |  1 +
 src/lib/notcurses.c |  8 +++++---
 src/lib/render.c    |  8 ++++----
 src/lib/sprite.c    | 12 +++++++++++-
 src/lib/visual.c    |  2 ++
 5 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/src/lib/internal.h b/src/lib/internal.h
index 53cd80f94..c0bf1acf5 100644
--- a/src/lib/internal.h
+++ b/src/lib/internal.h
@@ -812,6 +812,7 @@ 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);
 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);
diff --git a/src/lib/notcurses.c b/src/lib/notcurses.c
index fdcd8ab51..39432b572 100644
--- a/src/lib/notcurses.c
+++ b/src/lib/notcurses.c
@@ -1984,9 +1984,11 @@ void ncplane_yx(const ncplane* n, int* y, int* x){
 }
 
 void ncplane_erase(ncplane* n){
-  /*if(n->sprite){
-    sprixel_hide(n->sprite);
-  }*/
+  if(n->sprite){
+    // FIXME ideally we'd clear out the sprixel here, necessary for multiframe
+    // media with transparency, but it leads to intense flicker in sixel...=[
+    return;
+  }
   // we must preserve the background, but a pure cell_duplicate() would be
   // wiped out by the egcpool_dump(). do a duplication (to get the stylemask
   // and channels), and then reload.
diff --git a/src/lib/render.c b/src/lib/render.c
index 86c3b69f3..83840f415 100644
--- a/src/lib/render.c
+++ b/src/lib/render.c
@@ -1085,19 +1085,19 @@ notcurses_rasterize_inner(notcurses* nc, const ncpile* p, FILE* out){
   // we explicitly move the cursor at the beginning of each output line, so no
   // need to home it expliticly.
   update_palette(nc, out);
-fprintf(stderr, "pile %p ymax: %d xmax: %d\n", p, p->dimy + nc->stdplane->absy, p->dimx + nc->stdplane->absx);
+//fprintf(stderr, "pile %p ymax: %d xmax: %d\n", p, p->dimy + nc->stdplane->absy, p->dimx + nc->stdplane->absx);
   if(clean_sprixels(nc, p, out) < 0){
     return -1;
   }
-fprintf(stderr, "RASTERIZE CORE\n");
+//fprintf(stderr, "RASTERIZE CORE\n");
   if(rasterize_core(nc, p, out)){
     return -1;
   }
-fprintf(stderr, "RASTERIZE SPRIXELS\n");
+//fprintf(stderr, "RASTERIZE SPRIXELS\n");
   if(rasterize_sprixels(nc, p, out) < 0){
     return -1;
   }
-fprintf(stderr, "RASTERIZE CORE\n");
+//fprintf(stderr, "RASTERIZE CORE\n");
   if(rasterize_core(nc, p, out)){
     return -1;
   }
diff --git a/src/lib/sprite.c b/src/lib/sprite.c
index 3a0225523..e40d73589 100644
--- a/src/lib/sprite.c
+++ b/src/lib/sprite.c
@@ -10,6 +10,17 @@ void sprixel_free(sprixel* s){
   }
 }
 
+sprixel* sprixel_recycle(ncplane* n){
+  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 n->sprite;
+}
+
 // store the original (absolute) coordinates from which we moved, so that
 // we can invalidate them in sprite_draw().
 void sprixel_movefrom(sprixel* s, int y, int x){
@@ -52,7 +63,6 @@ sprixel* sprixel_by_id(const notcurses* nc, uint32_t id){
 sprixel* sprixel_alloc(ncplane* n, int dimy, int dimx){
   sprixel* ret = malloc(sizeof(sprixel));
   if(ret){
-fprintf(stderr, "LOADING UP %p with %p\n", ret, n);
     memset(ret, 0, sizeof(*ret));
     ret->n = n;
     ret->dimy = dimy;
diff --git a/src/lib/visual.c b/src/lib/visual.c
index 43d835f98..4dca586fb 100644
--- a/src/lib/visual.c
+++ b/src/lib/visual.c
@@ -608,6 +608,8 @@ ncplane* ncvisual_render_pixels(notcurses* nc, ncvisual* ncv, const struct blits
     if((ncv->spx = sprixel_alloc(n, rows, cols)) == NULL){
       goto err;
     }
+  }else{
+    ncv->spx = sprixel_recycle(n);
   }
   bargs.u.pixel.spx = ncv->spx;
   if(ncvisual_blit(ncv, disprows, dispcols, n, bset, disprows, dispcols, &bargs)){