symfony · fabpot · Jul 22, 2022 · Jul 21, 2022
@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+6.2
+---
+
+* Improve truecolor terminal detection in some cases
+* Add support for 256 color terminals (conversion from Ansi24 to Ansi8 if terminal is capable of it)
+
 6.1
 ---
 

@@ -117,17 +117,7 @@ private function parseColor(string $color, bool $background = false): string
         }
 
         if ('#' === $color[0]) {
-            $color = substr($color, 1);
-
-            if (3 === \strlen($color)) {
-                $color = $color[0].$color[0].$color[1].$color[1].$color[2].$color[2];
-            }
-
-            if (6 !== \strlen($color)) {
-                throw new InvalidArgumentException(sprintf('Invalid "%s" color.', $color));
-            }
-
-            return ($background ? '4' : '3').$this->convertHexColorToAnsi(hexdec($color));
+            return ($background ? '4' : '3').Terminal::getTermColorSupport()->convertFromHexToAnsiColorCode($color);
         }
 
         if (isset(self::COLORS[$color])) {
@@ -140,41 +130,4 @@ private function parseColor(string $color, bool $background = false): string
 
         throw new InvalidArgumentException(sprintf('Invalid "%s" color; expected one of (%s).', $color, implode(', ', array_merge(array_keys(self::COLORS), array_keys(self::BRIGHT_COLORS)))));
     }
-
-    private function convertHexColorToAnsi(int $color): string
-    {
-        $r = ($color >> 16) & 255;
-        $g = ($color >> 8) & 255;
-        $b = $color & 255;
-
-        // see https://github.com/termstandard/colors/ for more information about true color support
-        if ('truecolor' !== getenv('COLORTERM')) {
-            return (string) $this->degradeHexColorToAnsi($r, $g, $b);
-        }
-
-        return sprintf('8;2;%d;%d;%d', $r, $g, $b);
-    }
-
-    private function degradeHexColorToAnsi(int $r, int $g, int $b): int
-    {
-        if (0 === round($this->getSaturation($r, $g, $b) / 50)) {
-            return 0;
-        }
-
-        return (round($b / 255) << 2) | (round($g / 255) << 1) | round($r / 255);
-    }
-
-    private function getSaturation(int $r, int $g, int $b): int
-    {
-        $r = $r / 255;
-        $g = $g / 255;
-        $b = $b / 255;
-        $v = max($r, $g, $b);
-
-        if (0 === $diff = $v - min($r, $g, $b)) {
-            return 0;
-        }
-
-        return (int) $diff * 100 / $v;
-    }
 }
@@ -0,0 +1,124 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Console\Output;
+
+use Symfony\Component\Asset\Exception\InvalidArgumentException;
+
+/**
+ * @author Fabien Potencier <[email protected]>
+ * @author Julien Boudry <[email protected]>
+ */
+enum AnsiColorMode
+{
+    /**
+     * Classical 4-bit Ansi colors, including 8 classical colors and 8 bright color. Output syntax is "ESC[${foreGroundColorcode};${backGroundColorcode}m"
+     * Must be compatible with all terminals and it's the minimal version supported.
+     */
+    case Ansi4;
+
+    /**
+     * 8-bit Ansi colors (240 differents colors + 16 duplicate color codes, ensuring backward compatibility).
+     * Output syntax is: "ESC[38;5;${foreGroundColorcode};48;5;${backGroundColorcode}m"
+     * Should be compatible with most terminals.
+     */
+    case Ansi8;
+
+    /**
+     * 24-bit Ansi colors (RGB).
+     * Output syntax is: "ESC[38;2;${foreGroundColorcodeRed};${foreGroundColorcodeGreen};${foreGroundColorcodeBlue};48;2;${backGroundColorcodeRed};${backGroundColorcodeGreen};${backGroundColorcodeBlue}m"
+     * May be compatible with many modern terminals.
+     */
+    case Ansi24;
+
+    /**
+     * Converts an RGB hexadecimal color to the corresponding Ansi code.
+     */
+    public function convertFromHexToAnsiColorCode(string $hexColor): string
+    {
+        $hexColor = str_replace('#', '', $hexColor);
+
+        if (3 === \strlen($hexColor)) {
+            $hexColor = $hexColor[0].$hexColor[0].$hexColor[1].$hexColor[1].$hexColor[2].$hexColor[2];
+        }
+
+        if (6 !== \strlen($hexColor)) {
+            throw new InvalidArgumentException(sprintf('Invalid "#%s" color.', $hexColor));
+        }
+
+        $color = hexdec($hexColor);
+
+        $r = ($color >> 16) & 255;
+        $g = ($color >> 8) & 255;
+        $b = $color & 255;
+
+        return match ($this) {
+            self::Ansi4 => (string) $this->convertFromRGB($r, $g, $b),
+            self::Ansi8 => '8;5;'.((string) $this->convertFromRGB($r, $g, $b)),
+            self::Ansi24 => sprintf('8;2;%d;%d;%d', $r, $g, $b)
+        };
+    }
+
+    private function convertFromRGB(int $r, int $g, int $b): int
+    {
+        return match ($this) {
+            self::Ansi4 => $this->degradeHexColorToAnsi4($r, $g, $b),
+            self::Ansi8 => $this->degradeHexColorToAnsi8($r, $g, $b),
+            default => throw new InvalidArgumentException("RGB cannot be converted to {$this->name}.")
+        };
+    }
+
+    private function degradeHexColorToAnsi4(int $r, int $g, int $b): int
+    {
+        if (0 === round($this->getSaturation($r, $g, $b) / 50)) {
+            return 0;
+        }
+
+        return (int) ((round($b / 255) << 2) | (round($g / 255) << 1) | round($r / 255));
+    }
+
+    private function getSaturation(int $r, int $g, int $b): int
+    {
+        $r = $r / 255;
+        $g = $g / 255;
+        $b = $b / 255;
+        $v = max($r, $g, $b);
+
+        if (0 === $diff = $v - min($r, $g, $b)) {
+            return 0;
+        }
+
+        return (int) ((int) $diff * 100 / $v);
+    }
+
+    /**
+     * Inspired from https://github.com/ajalt/colormath/blob/e464e0da1b014976736cf97250063248fc77b8e7/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/Ansi256.kt code (MIT license).
+     */
+    private function degradeHexColorToAnsi8(int $r, int $g, int $b): int
+    {
+        if ($r === $g && $g === $b) {
+            if ($r < 8) {
+                return 16;
+            }
+
+            if ($r > 248) {
+                return 231;
+            }
+
+            return (int) round(($r - 8) / 247 * 24) + 232;
+        } else {
+            return 16 +
+                    (36 * (int) round($r / 255 * 5)) +
+                    (6 * (int) round($g / 255 * 5)) +
+                    (int) round($b / 255 * 5);
+        }
+    }
+}
@@ -11,12 +11,49 @@
 
 namespace Symfony\Component\Console;
 
+use Symfony\Component\Console\Output\AnsiColorMode;
+
 class Terminal
 {
     private static ?int $width = null;
     private static ?int $height = null;
     private static ?bool $stty = null;
 
+    /**
+     * About Ansi color types: https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
+     * For more information about true color support with terminals https://github.com/termstandard/colors/.
+     */
+    public static function getTermColorSupport(): AnsiColorMode
+    {
+        // Try with $COLORTERM first
+        if (\is_string($colorterm = getenv('COLORTERM'))) {
+            $colorterm = strtolower($colorterm);
+
+            if (str_contains($colorterm, 'truecolor')) {
+                return AnsiColorMode::Ansi24;
+            }
+
+            if (str_contains($colorterm, '256color')) {
+                return AnsiColorMode::Ansi8;
+            }
+        }
+
+        // Try with $TERM
+        if (\is_string($term = getenv('TERM'))) {
+            $term = strtolower($term);
+
+            if (str_contains($term, 'truecolor')) {
+                return AnsiColorMode::Ansi24;
+            }
+
+            if (str_contains($term, '256color')) {
+                return AnsiColorMode::Ansi8;
+            }
+        }
+
+        return AnsiColorMode::Ansi4;
+    }
+
     /**
      * Gets the terminal width.
      */

@@ -16,7 +16,7 @@
 
 class ColorTest extends TestCase
 {
-    public function testAnsiColors()
+    public function testAnsi4Colors()
     {
         $color = new Color();
         $this->assertSame(' ', $color->apply(' '));
@@ -33,21 +33,27 @@ public function testAnsiColors()
 
     public function testTrueColors()
     {
-        if ('truecolor' !== getenv('COLORTERM')) {
-            $this->markTestSkipped('True color not supported.');
-        }
+        $colorterm = getenv('COLORTERM');
+        putenv('COLORTERM=truecolor');
 
-        $color = new Color('#fff', '#000');
-        $this->assertSame("\033[38;2;255;255;255;48;2;0;0;0m \033[39;49m", $color->apply(' '));
+        try {
+            $color = new Color('#fff', '#000');
+            $this->assertSame("\033[38;2;255;255;255;48;2;0;0;0m \033[39;49m", $color->apply(' '));
 
-        $color = new Color('#ffffff', '#000000');
-        $this->assertSame("\033[38;2;255;255;255;48;2;0;0;0m \033[39;49m", $color->apply(' '));
+            $color = new Color('#ffffff', '#000000');
+            $this->assertSame("\033[38;2;255;255;255;48;2;0;0;0m \033[39;49m", $color->apply(' '));
+        } finally {
+            (false !== $colorterm) ? putenv('COLORTERM='.$colorterm) : putenv('COLORTERM');
+        }
     }
 
-    public function testDegradedTrueColors()
+    public function testDegradedTrueColorsToAnsi4()
     {
         $colorterm = getenv('COLORTERM');
+        $term = getenv('TERM');
+
         putenv('COLORTERM=');
+        putenv('TERM=');
 
         try {
             $color = new Color('#f00', '#ff0');
@@ -56,7 +62,28 @@ public function testDegradedTrueColors()
             $color = new Color('#c0392b', '#f1c40f');
             $this->assertSame("\033[31;43m \033[39;49m", $color->apply(' '));
         } finally {
-            putenv('COLORTERM='.$colorterm);
+            (false !== $colorterm) ? putenv('COLORTERM='.$colorterm) : putenv('COLORTERM');
+            (false !== $term) ? putenv('TERM='.$term) : putenv('TERM');
+        }
+    }
+
+    public function testDegradedTrueColorsToAnsi8()
+    {
+        $colorterm = getenv('COLORTERM');
+        $term = getenv('TERM');
+
+        putenv('COLORTERM=');
+        putenv('TERM=symfonyTest-256color');
+
+        try {
+            $color = new Color('#f57255', '#8993c0');
+            $this->assertSame("\033[38;5;210;48;5;146m \033[39;49m", $color->apply(' '));
+
+            $color = new Color('#000000', '#ffffff');
+            $this->assertSame("\033[38;5;16;48;5;231m \033[39;49m", $color->apply(' '));
+        } finally {
+            (false !== $colorterm) ? putenv('COLORTERM='.$colorterm) : putenv('COLORTERM');
+            (false !== $term) ? putenv('TERM='.$term) : putenv('TERM');
         }
     }
 }