From 08b65a86994241fa841785d61a7d17bd9f0290ec Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Sun, 14 Mar 2021 17:54:36 -0400
Subject: [PATCH] sprixels: introduce sprixel cache #1401

---
 src/lib/internal.h  | 17 +++++++++++++++++
 src/lib/notcurses.c | 11 +++++++++++
 src/lib/sprite.c    |  8 ++++++++
 src/tests/pixel.cpp | 17 +++++++++++++++++
 4 files changed, 53 insertions(+)
 create mode 100644 src/lib/sprite.c
 create mode 100644 src/tests/pixel.cpp

diff --git a/src/lib/internal.h b/src/lib/internal.h
index 84b0a845a..c97e61f6d 100644
--- a/src/lib/internal.h
+++ b/src/lib/internal.h
@@ -346,6 +346,19 @@ typedef struct ncpile {
   int dimy, dimx;             // rows and cols at time of render
 } ncpile;
 
+// there is a context-wide set of displayed pixel glyphs ("sprixels"); i.e.
+// these are independent of particular piles. there should never be very many
+// associated with a context (a dozen or so at max). with the kitty protocol,
+// we can register them, and then manipulate them by id. with the sixel
+// protocol, we just have to rewrite them.
+typedef struct sprixel {
+  char* glyph;  // glyph; can be quite large
+  int id;       // embedded into glusters field of nccell
+  int cols;
+  int rows;
+  struct sprixel* next;
+} sprixel;
+
 // the standard pile can be reached through ->stdplane.
 typedef struct notcurses {
   ncplane* stdplane; // standard plane, covers screen
@@ -377,6 +390,8 @@ typedef struct notcurses {
   pthread_mutex_t pilelock; // guards pile list, locks resize in render
   bool suppress_banner; // from notcurses_options
 
+  sprixel* sprixelcache; // list of pixel graphics currently displayed
+
   // desired margins (best-effort only), copied in from notcurses_options
   int margin_t, margin_b, margin_r, margin_l;
   int loglevel;
@@ -666,6 +681,8 @@ plane_debug(const ncplane* n, bool details){
   }
 }
 
+void sprixel_free(sprixel* s);
+
 static inline unsigned
 channels_pixel_p(uint64_t channels){
   return channels & CELL_PIXEL_GRAPHICS;
diff --git a/src/lib/notcurses.c b/src/lib/notcurses.c
index f816f7de8..7b543a8c1 100644
--- a/src/lib/notcurses.c
+++ b/src/lib/notcurses.c
@@ -946,6 +946,7 @@ notcurses* notcurses_core_init(const notcurses_options* opts, FILE* outfp){
   ret->margin_l = opts->margin_l;
   ret->margin_r = opts->margin_r;
   ret->cursory = ret->cursorx = -1;
+  ret->sprixelcache = NULL;
   memset(&ret->stats, 0, sizeof(ret->stats));
   memset(&ret->stashed_stats, 0, sizeof(ret->stashed_stats));
   reset_stats(&ret->stats);
@@ -1102,6 +1103,15 @@ ncpile_drop(notcurses* nc, ncpile** pile){
   }
 }
 
+static void
+free_sprixels(notcurses* nc){
+  while(nc->sprixelcache){
+    sprixel* tmp = nc->sprixelcache->next;
+    sprixel_free(nc->sprixelcache);
+    nc->sprixelcache = tmp;
+  }
+}
+
 // drop all piles and all planes, save the standard plane and its pile
 void notcurses_drop_planes(notcurses* nc){
   pthread_mutex_lock(&nc->pilelock);
@@ -1137,6 +1147,7 @@ int notcurses_stop(notcurses* nc){
     if(nc->ttyfd >= 0){
       ret |= close(nc->ttyfd);
     }
+    free_sprixels(nc);
     egcpool_dump(&nc->pool);
     free(nc->lastframe);
     free(nc->rstate.mstream);
diff --git a/src/lib/sprite.c b/src/lib/sprite.c
new file mode 100644
index 000000000..8eb8cb5aa
--- /dev/null
+++ b/src/lib/sprite.c
@@ -0,0 +1,8 @@
+#include "internal.h"
+
+void sprixel_free(sprixel* s){
+  if(s){
+    free(s->glyph);
+    free(s);
+  }
+}
diff --git a/src/tests/pixel.cpp b/src/tests/pixel.cpp
new file mode 100644
index 000000000..e43203204
--- /dev/null
+++ b/src/tests/pixel.cpp
@@ -0,0 +1,17 @@
+#include "main.h"
+
+TEST_CASE("Pixel") {
+  auto nc_ = testing_notcurses();
+  REQUIRE(nullptr != nc_);
+  ncplane* ncp_ = notcurses_stdplane(nc_);
+  REQUIRE(ncp_);
+  auto n_ = notcurses_stdplane(nc_);
+  REQUIRE(n_);
+
+  if(!notcurses_check_pixel_support(nc_)){
+    CHECK(!notcurses_stop(nc_));
+    return;
+  }
+
+  CHECK(!notcurses_stop(nc_));
+}