add compare_versions, don't use C=1 with kitty < 0.20.0

src/lib/termdesc.c

@@ -151,6 +151,49 @@ void free_terminfo_cache(tinfo* ti){
   free(ti->esctable);
 }
 
+// compare one terminal version against another. numerics, separated by
+// periods, and comparison ends otherwise (so "20.0 alpha" doesn't compare
+// as greater than "20.0", mainly). returns -1 if v1 < v2 (or v1 is NULL),
+// 0 if v1 == v2, or 1 if v1 > v2.
+static int
+compare_versions(const char* restrict v1, const char* restrict v2){
+  if(v1 == NULL){
+    return -1;
+  }
+  while(*v1 && *v2){
+    if(isdigit(*v1) && isdigit(*v2)){
+      if(*v1 > *v2){
+        return 1;
+      }
+      if(*v2 > *v1){
+        return -1;
+      }
+    }else if(isdigit(*v1)){
+      return 1;
+    }else if(isdigit(*v2)){
+      return -1;
+    }else if(*v1 != '.' && *v2 != '.'){
+      break;
+    }else if(*v1 != '.' || *v2 != '.'){
+      if(*v1 == '.'){
+        return 1;
+      }else{
+        return -1;
+      }
+    }
+    ++v1;
+    ++v2;
+  }
+  // can only get out here if at least one was not a period
+  if(*v1 == '.'){
+    return 1;
+  }
+  if(*v2 == '.'){
+    return -1;
+  }
+  return 0;
+}
+
 // tlen -- size of escape table. tused -- used bytes in same.
 // returns -1 if the starting location is >= 65535. otherwise,
 // copies tstr into the table, and sets up 1-biased index.
@@ -297,6 +340,10 @@ apply_term_heuristics(tinfo* ti, const char* termname, int fd,
     if(add_smulx_escapes(ti, tablelen, tableused)){
       return -1;
     }
+    // kitty only introduced C=1 in 0.20.0
+    if(compare_versions(ti->termversion, "0.20.0") < 0){
+      ti->sixel_maxy_pristine = INT_MAX;
+    }
   }else if(qterm == TERMINAL_ALACRITTY){
     termname = "Alacritty";
     ti->caps.quadrants = true;

src/lib/visual.c

@@ -970,6 +970,12 @@ ncplane* ncvisual_render_pixels(notcurses* nc, ncvisual* ncv, const struct blits
       bargs.u.pixel.cursor_hack = get_escape(&nc->tcache, ESCAPE_CIVIS);
     }
   }
+  // if we are kitty prior to 0.20.0, we set NCVISUAL_OPTION_SCROLL so that
+  // C=1 won't be supplied. we use sixel_maxy_pristine as a side channel to
+  // encode this version information.
+  if(nc->tcache.sixel_maxy_pristine){
+    bargs.flags |= NCVISUAL_OPTION_SCROLL;
+  }
   // FIXME need to pull off the ncpile's sprixellist if anything below fails!
   // at this point, disppixy/disppixx are the output geometry (might be larger
   // than scaledy/scaledx for sixel), while scaledy/scaledx are the scaled

src/media/ffmpeg.c

@@ -201,7 +201,7 @@ force_rgba(ncvisual* n){
         av_freep(&n->details->frame);
       }
     }
-    ncvisual_set_data(n, sframe->data[0], false);
+    ncvisual_set_data(n, sframe->data[0], true);
   }
   n->details->frame = sframe;
   return 0;
@@ -538,7 +538,7 @@ int ffmpeg_resize(ncvisual* n, int rows, int cols){
   if(n->owndata){
     av_frame_unref(n->details->frame);
   }
-  ncvisual_set_data(n, sframe->data[0], false);
+  ncvisual_set_data(n, sframe->data[0], true);
   n->details->frame = sframe;
 //fprintf(stderr, "SIZE SCALED: %d %d (%u)\n", n->details->frame->height, n->details->frame->width, n->details->frame->linesize[0]);
   return 0;
@@ -566,7 +566,7 @@ int ffmpeg_blit(ncvisual* ncv, int rows, int cols, ncplane* n,
 }
 
 void ffmpeg_details_seed(ncvisual* ncv){
-  ncv->details->frame->data[0] = NULL;
+  ncv->details->frame->data[0] = (uint8_t*)ncv->data;
   ncv->details->frame->data[1] = NULL;
   ncv->details->frame->linesize[0] = ncv->rowstride;
   ncv->details->frame->linesize[1] = 0;