Rainbow terminal console text and/or background

rainbow.py

"""Rainbow print loop using ANSI escape sequences. Press Ctrl+C to stop.
By Cees Timmerman
2020-03-06 First version.
2024-03-27 Fixed on Windows 11."""
import time

CSI = "\x1b[" # Control Sequence Introducer.
# https://en.wikipedia.org/wiki/ANSI_escape_code#Fe_Escape_sequences
# On Windows 11, C1 control code 155 "\x9b" only works the same in VS Code.
# https://github.com/microsoft/terminal/issues/10310

RESET = CSI+"0m"
FGWHITE = CSI+"38;2;255;255;255m"
FGBLACK = CSI+"38;2;0;0;0m"  # [30m isn't always black: https://en.wikipedia.org/wiki/ANSI_escape_code
s = 17  # 1, 3, 5, 15, 17, 51, 85, 255, or any integer between.
r = 255; g = 0; b = 0
rs = 0; gs = s; bs = 0
while True:
	r += rs; g += gs; b += bs
	if rs > 0 and r >= 255: r = 255; rs = 0; bs = -s
	elif gs > 0 and g >= 255: g = 255; gs = 0; rs = -s
	elif bs > 0 and b >= 255: b = 255; bs = 0; gs = -s
	elif rs < 0 and r <= 0: r = 0; rs = 0; bs = s
	elif gs < 0 and g <= 0: g = 0; gs = 0; rs = s
	elif bs < 0 and b <= 0: b = 0; bs = 0; gs = s
	foreground = CSI+f"38;2;{r};{g};{b}m"
	background = CSI+f"48;2;{r};{g};{b}m"
	text = f"({r: >3},{g: >3},{b: >3})"
	#print(foreground + text)
	#print(background + FGBLACK + text + RESET)
	### Full line ###
	#print(background+"\n"+FGBLACK+text, end="")
	print(background+"\n"+RESET+foreground+text, end="")
	#print(background)
	time.sleep(0.02)

https://en.wikipedia.org/wiki/HSL_and_HSV#/media/File:HSV-RGB-comparison.svg said more than the rest of the article on how to not get a muddy spectrum yellow described here.

To enable escape sequences in the Windows Command Prompt or PowerShell:

• Just add |Out-Host in PowerShell, e.g. py rainbow.py |Out-Host
• Or run this and restart PowerShell: Set-ItemProperty HKCU:\Console VirtualTerminalLevel -Type DWORD 1