Module: Tempest::Kitty

Defined in:
lib/tempest/kitty.rb

Overview

Encodes an image as a Kitty graphics protocol “transmit and display” escape sequence. Pure transformation: no I/O beyond optionally reading the bytes from a path. Output is meant to be inlined into a single terminal row when called with the defaults (rows: 1, cols: 2).

Protocol reference:

https://sw.kovidgoyal.net/kitty/graphics-protocol/

Key control opcodes used:

a=T   transmit and immediately display
f=100 source bytes are PNG
r=N   render at N terminal rows
c=N   render at N terminal columns
C=1   do not advance the cursor (image is drawn at the current cell,
      the cursor stays where it was)
m=0/1 multi-chunk marker: 1 = more chunks follow, 0 = final chunk

Constant Summary collapse

CHUNK_BYTES = 
4096

Class Method Summary collapse

Class Method Details

.inline(png, rows: 1, cols: 2) ⇒ Object 



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# File 'lib/tempest/kitty.rb', line 27

def inline(png, rows: 1, cols: 2)
  bytes = png.is_a?(String) && File.file?(png) ? File.binread(png) : png
  data = Base64.strict_encode64(bytes)
  out = String.new
  pos = 0
  first = true
  while pos < data.bytesize
    piece = data.byteslice(pos, CHUNK_BYTES)
    pos += CHUNK_BYTES
    more = pos < data.bytesize ? 1 : 0
    controls = if first
      "a=T,f=100,r=#{rows},c=#{cols},C=1,m=#{more}"
    else
      "m=#{more}"
    end
    out << "\e_G#{controls};#{piece}\e\\"
    first = false
  end
  out
end