Add an example for displaying a PNG with bash

docs/graphics-protocol.rst

@@ -112,15 +112,40 @@ kitty.
 A minimal example
 ------------------
 
-Some minimal python code to display PNG images in kitty, using the most basic
+Some minimal code to display PNG images in kitty, using the most basic
 features of the graphics protocol:
 
+.. tab:: Bash
+
+    .. code-block:: sh
+
+        #!/bin/bash
+        transmit_png() {
+            data=$(base64 "$1")
+            data="${data//[[:space:]]}"
+            builtin local pos=0
+            builtin local chunk_size=4096
+            while [ $pos -lt ${#data} ]; do
+                builtin printf "\e_G"
+                [ $pos = "0" ] && printf "a=T,f=100,"
+                builtin local chunk="${data:$pos:$chunk_size}"
+                pos=$(($pos+$chunk_size))
+                [ $pos -lt ${#data} ] && builtin printf "m=1"
+                [ ${#chunk} -gt 0 ] && builtin printf ";%s" "${chunk}"
+                builtin printf "\e\\"
+            done
+        }
+
+        transmit_png "$1"
+
+.. tab:: Python
+
     .. code-block:: python
 
+        #!/usr/bin/python
         import sys
         from base64 import standard_b64encode
 
-
         def serialize_gr_command(**cmd):
             payload = cmd.pop('payload', None)
             cmd = ','.join(f'{k}={v}' for k, v in cmd.items())
@@ -133,7 +158,6 @@ features of the graphics protocol:
             w(b'\033\\')
             return b''.join(ans)
 
-
         def write_chunked(**cmd):
             data = standard_b64encode(cmd.pop('data'))
             while data:
@@ -144,15 +168,15 @@ features of the graphics protocol:
                 sys.stdout.flush()
                 cmd.clear()
 
-
         with open(sys.argv[-1], 'rb') as f:
             write_chunked(a='T', f=100, data=f.read())
 
 
-Save this script as :file:`png.py`, then you can use it to display any PNG
+Save this script as :file:`send-png`, then you can use it to display any PNG
 file in kitty as::
 
-   python png.py file.png
+    chmod +x send-png
+    ./send-png file.png
 
 
 The graphics escape code