Make the colorized build output readable on a light background

This fixes the readability of colorized output of compile.sh when
running on a terminal with a light background.  It uses the COLORFGBG
environment variable similarly to how the ip(8) command does.

Signed-off-by: Darsey Litzenberger <dlitz@dlitz.net>

lib/tools/common/armbian_utils.py

@@ -20,6 +20,8 @@ from pathlib import Path
 
 import sys
 
+from common.term_colors import background_dark_or_light
+
 REGEX_WHITESPACE_LINEBREAK_COMMA_SEMICOLON = r"[\s,;\n]+"
 
 ARMBIAN_BOARD_CONFIG_REGEX_GENERIC = r"^(?!\s)(?:[export |declare \-g]?)+([A-Z0-9_]+)=(?:'|\")(.*)(?:'|\")"
@@ -80,14 +82,24 @@ def setup_logging():
 		if is_debug():
 			level = "DEBUG"
 		format = "%(message)s"
-		styles = {
-			'trace': {'color': 'white', 'bold': False},
-			'debug': {'color': 'white', 'bold': False},
-			'info': {'color': 'green', 'bold': True},
-			'warning': {'color': 'yellow', 'bold': True},
-			'error': {'color': 'red'},
-			'critical': {'bold': True, 'color': 'red'}
-		}
+		if background_dark_or_light() == 'light':
+			styles = {
+				'trace': {'color': 'black', 'bright': True},
+				'debug': {'color': 'black', 'bright': True},
+				'info': {'color': 'green', 'bold': True, 'faint': True},
+				'warning': {'color': 'yellow', 'bold': True, 'faint': True},
+				'error': {'color': 'red'},
+				'critical': {'bold': True, 'color': 'red'}
+			}
+		else:
+			styles = {
+				'trace': {'color': 'white', 'bold': False},
+				'debug': {'color': 'white', 'bold': False},
+				'info': {'color': 'green', 'bold': True},
+				'warning': {'color': 'yellow', 'bold': True},
+				'error': {'color': 'red'},
+				'critical': {'bold': True, 'color': 'red'}
+			}
 		coloredlogs.install(level=level, stream=sys.stderr, isatty=True, fmt=format, level_styles=styles)
 	except ImportError:
 		level = logging.INFO

lib/tools/common/patching_utils.py

@@ -20,6 +20,7 @@ from unidecode import unidecode
 from unidiff import PatchSet
 
 from common.patching_config import PatchingConfig
+from common.term_colors import background_dark_or_light
 
 MAGIC_MBOX_MARKER_STANDARD = "Mon Sep 17 00:00:00 2001"
 MAGIC_MBOX_MARKER_B4 = "git@z Thu Jan  1 00:00:00 1970"
@@ -703,11 +704,12 @@ class PatchInPatchFile:
 				color = "yellow"
 			else:
 				color = "red"
+		bold = 'bold dim' if background_dark_or_light() == 'light' else 'bold'
 		# @TODO: once our ansi-haste supports it, use [link url=file://blaaa]
 		if self.parent.multiple_patches_in_file:
-			return f"[bold][{color}]{self.markdown_name(skip_markdown=True)}[/bold](:{self.counter})"
+			return f"[{bold}][{color}]{self.markdown_name(skip_markdown=True)}[/{bold}](:{self.counter})"
 		else:
-			return f"[bold {color}]{self.markdown_name(skip_markdown=True)}"
+			return f"[{bold} {color}]{self.markdown_name(skip_markdown=True)}"
 
 	def rich_patch_output(self):
 		ret = self.patch_output
@@ -716,10 +718,11 @@ class PatchInPatchFile:
 			'yellow': ['with fuzz', 'offset ', ' hunks ignored', ' hunk ignored'],
 			'red': ['hunk FAILED', 'hunks FAILED']
 		}
+		bold = 'bold dim' if background_dark_or_light() == 'light' else 'bold'
 		# use Rich's syntax highlighting to highlight with color
 		for color in color_tags:
 			for tag in color_tags[color]:
-				ret = ret.replace(tag, f"[bold {color}]{tag}[/bold {color}]")
+				ret = ret.replace(tag, f"[{bold} {color}]{tag}[/{bold} {color}]")
 		return ret
 
 	def apply_patch_date_to_files(self, working_dir, options):

lib/tools/common/term_colors.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+#
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2024 Darsey Litzenberger, dlitz@dlitz.net
+#
+# This file is a part of the Armbian Build Framework
+# https://github.com/armbian/build/
+#
+
+import os
+
+
+def background_dark_or_light():
+	"""
+	Returns:
+		'dark' if the terminal background is dark,
+		'light' if the terminal background is light, or
+		'' if the terminal background color is unknown.
+	"""
+	colorfgbg = os.environ.get("COLORFGBG", "")
+	try:
+		_, bg = colorfgbg.split(';')
+		bg = int(bg)
+	except ValueError:
+		return ""
+	if 0 <= bg <= 6 or bg == 8:
+		return "dark"
+	elif bg == 7 or 9 <= bg <= 15:
+		return "light"
+	return ""