update doc, and refactor color utility functions

Author: jedib0t

text/256_COLOR_ANALYSIS.md

@@ -15,6 +15,11 @@ Used heavily in the other packages in this repo ([list](../list),
     - Foreground colors (Black, Red, Green, Yellow, Blue, Magenta, Cyan, White)
     - Background colors (matching foreground set)
     - Hi-intensity variants for both foreground and background
+    - **256-color palette support** - Extended color support for terminals
+      - Standard 16 colors (0-15)
+      - RGB cube colors (16-231) - 216 colors organized in a 6x6x6 cube
+      - Grayscale colors (232-255) - 24 shades of gray
+      - Helper functions: `Fg256Color(index)`, `Bg256Color(index)`, `Fg256RGB(r, g, b)`, `Bg256RGB(r, g, b)`
     - Text attributes (Bold, Faint, Italic, Underline, Blink, Reverse, Concealed, CrossedOut)
     - Automatic color detection based on environment variables (`NO_COLOR`, `FORCE_COLOR`, `TERM`)
     - Global enable/disable functions for colors
@@ -76,6 +81,7 @@ Used heavily in the other packages in this repo ([list](../list),
     - `EscSeqParser` - Parser for advanced escape sequence parsing and tracking
       - Supports both CSI (Control Sequence Introducer) and OSI (Operating System Command) formats
       - Tracks active formatting codes and can generate consolidated escape sequences
+      - Full support for 256-color escape sequences (`\x1b[38;5;n`m` and `\x1b[48;5;n`m`)
 
 ### Cursor Control
 

text/README.md

@@ -3,6 +3,12 @@
 
 package text
 
+import "os"
+
 func areANSICodesSupported() bool {
-	return true
+	// On Unix systems, ANSI codes are generally supported unless TERM is "dumb"
+	// This is a basic check; 256-color sequences are ANSI sequences and will
+	// be handled by terminals that support them (or ignored by those that don't)
+	term := os.Getenv("TERM")
+	return term != "dumb"
 }

text/ansi_unix.go

@@ -9,6 +9,7 @@ import (
 	"sync"
 )
 
+// colorsEnabled is true if colors are enabled and supported by the terminal.
 var colorsEnabled = areColorsOnInTheEnv() && areANSICodesSupported()
 
 // DisableColors (forcefully) disables color coding globally.
@@ -21,17 +22,24 @@ func EnableColors() {
 	colorsEnabled = true
 }
 
-// areColorsOnInTheEnv returns true is colors are not disable using
+// areColorsOnInTheEnv returns true if colors are not disabled using
 // well known environment variables.
 func areColorsOnInTheEnv() bool {
-	if os.Getenv("FORCE_COLOR") == "1" {
+	// FORCE_COLOR takes precedence - if set to a truthy value, enable colors
+	forceColor := os.Getenv("FORCE_COLOR")
+	if forceColor != "" && forceColor != "0" && forceColor != "false" {
 		return true
 	}
-	if os.Getenv("NO_COLOR") == "" || os.Getenv("NO_COLOR") == "0" {
-		return os.Getenv("TERM") != "dumb"
+
+	// NO_COLOR: if set to any non-empty value (except "0"), disable colors
+	// Note: "0" is treated as "not set" to allow explicit enabling via NO_COLOR=0
+	noColor := os.Getenv("NO_COLOR")
+	if noColor != "" && noColor != "0" {
+		return false
 	}
 
-	return false
+	// Default: check TERM - if not "dumb", assume colors are supported
+	return os.Getenv("TERM") != "dumb"
 }
 
 // The logic here is inspired from github.com/fatih/color; the following is