make it clear that sixel is not yet supported

USAGE.md

@@ -2679,7 +2679,7 @@ typedef enum {
   NCBLIT_4x1,     // four vertical levels     █▆▄▂
   NCBLIT_BRAILLE, // 4 rows, 2 cols (braille) ⡀⡄⡆⡇⢀⣀⣄⣆⣇⢠⣠⣤⣦⣧⢰⣰⣴⣶⣷⢸⣸⣼⣾⣿
   NCBLIT_8x1,     // eight vertical levels    █▇▆▅▄▃▂▁
-  NCBLIT_SIXEL,   // 6 rows, 1 col (RGB), spotty support among terminals
+  NCBLIT_SIXEL,   // not yet implemented
 } ncblitter_e;
 
 // Lex a blitter.

doc/man/man3/notcurses_capabilities.3.md

@@ -59,7 +59,7 @@ multimedia support capable of decoding videos.
 UTF-8 encoding, and the locale was successfully loaded.
 
 **notcurses_cansixel** returns **true** if the terminal advertises
-support for Sixel, and Notcurses has been built with Sixel support.
+support for Sixel.
 
 # BUGS
 

doc/man/man3/notcurses_visual.3.md

@@ -25,7 +25,7 @@ typedef enum {
   NCBLIT_4x1,     // four vertical levels
   NCBLIT_BRAILLE, // 4 rows, 2 cols (braille)
   NCBLIT_8x1,     // eight vertical levels
-  NCBLIT_SIXEL,   // 6 rows, 1 col (RGB)
+  NCBLIT_SIXEL,   // not yet implemented
 } ncblitter_e;
 
 #define NCVISUAL_OPTION_NODEGRADE 0x0001
@@ -154,7 +154,7 @@ The different **ncblitter_e** values select from among available glyph sets:
 * **NCBLIT_4x1**: Adds ¼ and ¾ blocks (▂▆) to **NCBLIT_2x1**.
 * **NCBLIT_BRAILLE**: 4 rows and 2 columns of braille (⡀⡄⡆⡇⢀⣀⣄⣆⣇⢠⣠⣤⣦⣧⢰⣰⣴⣶⣷⢸⣸⣼⣾⣿).
 * **NCBLIT_8x1**: Adds ⅛, ⅜, ⅝, and ⅞ blocks (▇▅▃▁) to **NCBLIT_4x1**.
-* **NCBLIT_SIXEL**: Sixel, a 6-by-1 RGB pixel arrangement.
+* **NCBLIT_SIXEL**: Not yet implemented.
 
 **NCBLIT_4x1** and **NCBLIT_8x1** are intended for use with plots, and are
 not really applicable for general visuals.
@@ -205,7 +205,8 @@ radians for **rads**, but this will change soon.
 **NCBLIT_SIXEL** is not yet implemented, and is only infrequently supported
 among terminals.
 
-Some fonts are lacking the Braille characters necessary for **NCBLIT_BRAILLE**.
+Bad font support can ruin **NCBLIT_2x2**, **NCBLIT_3x2**, **NCBLIT_4x1**,
+**NCBLIT_BRAILLE**, and **NCBLIT_8x1**.
 
 # SEE ALSO
 

include/notcurses/notcurses.h

@@ -62,7 +62,7 @@ typedef enum {
   NCBLIT_4x1,     // four vertical levels     █▆▄▂
   NCBLIT_BRAILLE, // 4 rows, 2 cols (braille) ⡀⡄⡆⡇⢀⣀⣄⣆⣇⢠⣠⣤⣦⣧⢰⣰⣴⣶⣷⢸⣸⣼⣾⣿
   NCBLIT_8x1,     // eight vertical levels    █▇▆▅▄▃▂▁
-  NCBLIT_SIXEL,   // 6 rows, 1 col (RGB), spotty support among terminals
+  NCBLIT_SIXEL,   // not yet implemented
 } ncblitter_e;
 
 // Alignment within a plane or terminal. Left/right-justified, or centered.

rust/src/types/plane.rs

@@ -82,7 +82,7 @@ pub const NCBLIT_BRAILLE: NcBlitter = crate::ncblitter_e_NCBLIT_BRAILLE;
 /// the blitter is automatically chosen
 pub const NCBLIT_DEFAULT: NcBlitter = crate::ncblitter_e_NCBLIT_DEFAULT;
 
-/// 6 rows, 1 col (RGB), spotty support among terminals
+/// not yet implemented
 pub const NCBLIT_SIXEL: NcBlitter = crate::ncblitter_e_NCBLIT_SIXEL;
 
 /// How to scale an [`NcVisual`](type.NcVisual.html) during rendering