From 83e71f3c4ddd3c12c54e94d39a4c1b01fc8b951a Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Thu, 5 Aug 2021 16:56:09 -0400
Subject: [PATCH] detect kitty graphics support via query #1998

---
 src/lib/input.c    | 33 ++++++++++++++++++++++++++++++++-
 src/lib/input.h    |  3 ++-
 src/lib/termdesc.c | 25 +++++++++++++++++--------
 3 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/src/lib/input.c b/src/lib/input.c
index a2e0e8dc93..486f82838d 100644
--- a/src/lib/input.c
+++ b/src/lib/input.c
@@ -777,6 +777,9 @@ typedef enum {
   STATE_XTGETTCAP_TERMNAME1, // got property 544E, 'TN' (terminal name) first hex nibble
   STATE_XTGETTCAP_TERMNAME2, // got property 544E, 'TN' (terminal name) second hex nibble
   STATE_DCS_DRAIN,  // throw away input until we hit escape
+  STATE_APC,        // application programming command, starts with \x1b_
+  STATE_APC_DRAIN,  // looking for \x1b
+  STATE_APC_ST,     // looking for ST
   STATE_BG1,        // got '1'
   STATE_BG2,        // got second '1'
   STATE_BGSEMI,     // got '11;', draining string to ESC ST
@@ -831,6 +834,7 @@ typedef struct query_state {
 
   bool xtgettcap_good;   // high when we've received DCS 1
   bool appsync;          // application-synchronized updates advertised
+  bool kittygraphics;    // kitty graphics were advertised
 } query_state;
 
 static int
@@ -1038,6 +1042,26 @@ pump_control_read(query_state* inits, unsigned char c){
         inits->state = STATE_NULL;
       }else if(c == '1'){
         inits->state = STATE_BG1;
+      }else if(c == '_'){
+        inits->state = STATE_APC;
+      }
+      break;
+    case STATE_APC:
+      if(c == 'G'){
+        inits->kittygraphics = true;
+      }
+      inits->state = STATE_APC_DRAIN;
+      break;
+    case STATE_APC_DRAIN:
+      if(c == '\x1b'){
+        inits->state = STATE_APC_ST;
+      }
+      break;
+    case STATE_APC_ST:
+      if(c == '\\'){
+        inits->state = STATE_NULL;
+      }else{
+        inits->state = STATE_APC_DRAIN;
       }
       break;
     case STATE_BG1:
@@ -1464,7 +1488,7 @@ control_read(int ttyfd, query_state* qstate){
 
 int ncinputlayer_init(tinfo* tcache, FILE* infp, queried_terminals_e* detected,
                       unsigned* appsync, int* cursor_y, int* cursor_x,
-                      ncsharedstats* stats){
+                      ncsharedstats* stats, unsigned* kittygraphs){
   ncinputlayer* nilayer = &tcache->input;
   if(pthread_mutex_init(&nilayer->lock, NULL)){
     return -1;
@@ -1515,6 +1539,13 @@ int ncinputlayer_init(tinfo* tcache, FILE* infp, queried_terminals_e* detected,
       tcache->pixy = inits.pixelheight;
       tcache->pixx = inits.pixelwidth;
     }
+    if(inits.kittygraphics){ // kitty trumps sixel
+      loginfo("advertised kitty; disabling sixel\n");
+      tcache->color_registers = 0;
+      tcache->sixel_maxx = 0;
+      tcache->sixel_maxy = 0;
+      *kittygraphs = true;
+    }
   }
   return 0;
 }
diff --git a/src/lib/input.h b/src/lib/input.h
index af2d58f1d5..acd09780e1 100644
--- a/src/lib/input.h
+++ b/src/lib/input.h
@@ -46,7 +46,8 @@ typedef enum {
 int ncinputlayer_init(struct tinfo* tcache, FILE* infp,
                       queried_terminals_e* detected, unsigned* appsync,
                       int* cursor_y, int* cursor_x,
-                      struct ncsharedstats* stats);
+                      struct ncsharedstats* stats,
+                      unsigned* kittygraphs);
 
 void ncinputlayer_stop(struct ncinputlayer* nilayer);
 
diff --git a/src/lib/termdesc.c b/src/lib/termdesc.c
index ae80c9db7e..014d1e42a1 100644
--- a/src/lib/termdesc.c
+++ b/src/lib/termdesc.c
@@ -345,7 +345,12 @@ init_terminfo_esc(tinfo* ti, const char* name, escape_e idx,
 // non-standard CSI for total pixel geometry
 #define GEOMPIXEL "\x1b[14t"
 
+// query for kitty graphics. if they are supported, we'll get a response to
+// this using the kitty response syntax. otherwise, we'll get nothing.
+#define KITTYQUERY "\x1b_Gi=1,a=q;\x1b\\"
+
 #define DIRECTIVES CSI_BGQ \
+                   KITTYQUERY \
                    SUMQUERY \
                    "\x1b[?1;3;256S" /* try to set 256 cregs */ \
                    CREGSXTSM \
@@ -542,8 +547,6 @@ apply_term_heuristics(tinfo* ti, const char* termname, int fd,
         return -1;
       }
     }
-    // wezterm supports iTerm2's graphic protocol, but we'd rather use Sixel.
-    // once it adds Kitty, we'll prefer that.
   }else if(qterm == TERMINAL_XTERM){
     termname = "XTerm";
     // xterm 357 added color palette escapes XT{PUSH,POP,REPORT}COLORS
@@ -830,8 +833,9 @@ int interrogate_terminfo(tinfo* ti, int fd, unsigned utf8, unsigned noaltscreen,
     cursor_y = &foolcursor_y;
   }
   *cursor_x = *cursor_y = -1;
+  unsigned kittygraphs = 0;
   if(ncinputlayer_init(ti, stdin, &qterm, &appsync_advertised,
-                       cursor_y, cursor_x, stats)){
+                       cursor_y, cursor_x, stats, &kittygraphs)){
     goto err;
   }
   if(nocbreak){
@@ -859,11 +863,16 @@ int interrogate_terminfo(tinfo* ti, int fd, unsigned utf8, unsigned noaltscreen,
     goto err;
   }
   build_supported_styles(ti);
-  // our current sixel quantization algorithm requires at least 64 color
-  // registers. we make use of no more than 256. this needs to happen
-  // after heuristics, since the choice of sixel_init() depends on it.
-  if(ti->color_registers >= 64){
-    setup_sixel_bitmaps(ti, fd, invertsixel);
+  if(ti->pixel_draw == NULL){
+    if(kittygraphs){
+      setup_kitty_bitmaps(ti, fd, KITTY_SELFREF);
+    }
+    // our current sixel quantization algorithm requires at least 64 color
+    // registers. we make use of no more than 256. this needs to happen
+    // after heuristics, since the choice of sixel_init() depends on it.
+    if(ti->color_registers >= 64){
+      setup_sixel_bitmaps(ti, fd, invertsixel);
+    }
   }
   return 0;