release: v3.2.0 - Enterprise Edition with Live Web Dashboard, PDF/Excel Exporters, Framework Stubs & 110 WCAG Rules

src/Rules/ColorBlindnessContrast.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace YakNet\AccessibilityConsole\Rules;
+
+use DOMElement;
+use Spatie\Color\Hex;
+use YakNet\AccessibilityConsole\Color\Contrast\ContrastRatioCalculator;
+use YakNet\AccessibilityConsole\Color\Simulators\DeuteranopiaSimulator;
+use YakNet\AccessibilityConsole\Color\Simulators\ProtanopiaSimulator;
+use YakNet\AccessibilityConsole\Core\Severity;
+use YakNet\AccessibilityConsole\Core\Violation;
+use YakNet\AccessibilityConsole\Core\WCAGStandard;
+
+class ColorBlindnessContrast extends AbstractRule
+{
+    public function getId(): string { return 'WCAG_1_4_1_COLOR_BLINDNESS_CONTRAST'; }
+    public function getDescription(): string { return 'Text and background color contrast must remain accessible (minimum 4.5:1) under color vision deficiency simulations (Deuteranopia, Protanopia).'; }
+    public function getStandard(): WCAGStandard { return WCAGStandard::AA; }
+    public function getSeverity(): Severity { return Severity::WARNING; }
+    public function getLevel(): int { return 4; }
+
+    public function check(DOMElement $element): ?Violation
+    {
+        if (!$element->hasAttribute('style')) {
+            return null;
+        }
+
+        $style = $element->getAttribute('style');
+        $colorHex = $this->extractColorFromStyle($style, 'color');
+        $bgHex = $this->extractColorFromStyle($style, 'background-color') ?? $this->extractColorFromStyle($style, 'background');
+
+        if (!$colorHex || !$bgHex) {
+            return null;
+        }
+
+        try {
+            $fgRgb = Hex::fromString($colorHex)->toRgb();
+            $bgRgb = Hex::fromString($bgHex)->toRgb();
+        } catch (\Throwable) {
+            return null;
+        }
+
+        // Simulate Deuteranopia & Protanopia using dedicated simulators
+        $simulations = [
+            'Deuteranopia' => [
+                'fg' => DeuteranopiaSimulator::simulate($fgRgb),
+                'bg' => DeuteranopiaSimulator::simulate($bgRgb),
+            ],
+            'Protanopia' => [
+                'fg' => ProtanopiaSimulator::simulate($fgRgb),
+                'bg' => ProtanopiaSimulator::simulate($bgRgb),
+            ],
+        ];
+
+        foreach ($simulations as $type => $sim) {
+            $contrast = ContrastRatioCalculator::calculate($sim['fg'], $sim['bg']);
+            if ($contrast < 4.5) {
+                return $this->createViolation(
+                    $element,
+                    sprintf('Insufficient color contrast (%.2f:1) under %s color blindness simulation (minimum 4.5:1 required).', $contrast, $type),
+                    sprintf('Adjust foreground color (%s) or background color (%s) to increase contrast for users with %s.', $colorHex, $bgHex, $type)
+                );
+            }
+        }
+
+        return null;
+    }
+
+    private function extractColorFromStyle(string $style, string $property): ?string
+    {
+        if (preg_match('/' . preg_quote($property, '/') . '\s*:\s*(#[0-9a-fA-F]{3,6})/i', $style, $matches)) {
+            $hex = $matches[1];
+            if (strlen($hex) === 4) {
+                $hex = '#' . $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
+            }
+            return $hex;
+        }
+        return null;
+    }
+}