Support alpha in hexadecimal colors

webapp/src/Controller/Jury/SubmissionController.php

@@ -1240,7 +1240,7 @@ protected function determineFileChanged(array $files, array $oldFiles): array
                     }
                 }
             }
-            if($isNewFile) {
+            if ($isNewFile) {
                 $result['addedfiles'][] = $newfile;
             }
         }

webapp/src/Entity/ContestProblem.php

@@ -261,7 +261,7 @@ public function validate(ExecutionContextInterface $context): void
     {
         if ($this->getColor() && Utils::convertToHex($this->getColor()) === null) {
             $context
-                ->buildViolation('This is not a valid color')
+                ->buildViolation('This is not a valid color.')
                 ->atPath('color')
                 ->addViolation();
         }

webapp/src/Service/EventLogService.php

@@ -487,7 +487,9 @@
                 $awards = [];
                 $this->dj->withAllRoles(function () use ($url, &$awards) {
                     $response = $this->dj->internalApiRequest($url);
-                    if ( !empty($response) ) $awards = Utils::jsonDecode($response);
+                    if (!empty($response)) {
+                      $awards = Utils::jsonDecode($response);
+                    }
                 });
                 foreach ($awards as $award) {
                     $this->insertEvent($contest, 'awards', $award['id'], $award);

webapp/src/Service/ExternalContestSourceService.php

@@ -1050,7 +1050,12 @@ protected function validateAndUpdateProblem(Event $event, EventData $data): void
             );
             $contestProblem->setShortname($data->label);
         }
-        if ($contestProblem->getColor() !== ($data->rgb)) {
+        if (preg_match('/^#[[:xdigit:]]{3}(?:[[:xdigit:]]{3}){0,2}$/', $data->rgb)) {
+            $this->logger->warning(
+                'Contest problem color does not match between feed (%s) and local (%s), but feed is invalid.',
+                [$data->rgb, $contestProblem->getColor()]
+            );
+        } elseif ($contestProblem->getColor() !== ($data->rgb)) {
             $this->logger->warning(
                 'Contest problem color does not match between feed (%s) and local (%s), updating',
                 [$data->rgb, $contestProblem->getColor()]

webapp/src/Twig/TwigExtension.php

@@ -1179,64 +1179,14 @@ public function fileTypeIcon(string $type): string
         return 'fas fa-file-' . $iconName;
     }
 
-    private function relativeLuminance(string $rgb): float
-    {
-        // See https://en.wikipedia.org/wiki/Relative_luminance
-        [$r, $g, $b] = Utils::parseHexColor($rgb);
-
-        [$lr, $lg, $lb] = [
-            pow($r / 255, 2.4),
-            pow($g / 255, 2.4),
-            pow($b / 255, 2.4),
-        ];
-
-        return 0.2126 * $lr + 0.7152 * $lg + 0.0722 * $lb;
-    }
-
-    private function apcaContrast(string $fgColor, string $bgColor): float
-    {
-        // Based on WCAG 3.x (https://www.w3.org/TR/wcag-3.0/)
-        $luminanceForeground = $this->relativeLuminance($fgColor);
-        $luminanceBackground = $this->relativeLuminance($bgColor);
-
-        $contrast = ($luminanceBackground > $luminanceForeground)
-            ? (pow($luminanceBackground, 0.56) - pow($luminanceForeground, 0.57)) * 1.14
-            : (pow($luminanceBackground, 0.65) - pow($luminanceForeground, 0.62)) * 1.14;
-
-        return round($contrast * 100, 2);
-    }
-
-    /**
-     * @return array{string, string}
-     */
-    private function hexToForegroundAndBorder(string $rgb): array
-    {
-        $background = Utils::parseHexColor($rgb);
-
-        // Pick a border that's a bit darker.
-        $darker = $background;
-        $darker[0] = max($darker[0] - 64, 0);
-        $darker[1] = max($darker[1] - 64, 0);
-        $darker[2] = max($darker[2] - 64, 0);
-        $border    = Utils::rgbToHex($darker);
-
-        // Pick the text color with the biggest absolute contrast.
-        $contrastWithWhite = $this->apcaContrast('#ffffff', $rgb);
-        $contrastWithBlack = $this->apcaContrast('#000000', $rgb);
-
-        $foreground = (abs($contrastWithBlack) > abs($contrastWithWhite)) ? '#000000' : '#ffffff';
-
-        return [$foreground, $border];
-    }
-
     public function problemBadge(ContestProblem $problem, bool $grayedOut = false): string
     {
         $rgb = Utils::convertToHex($problem->getColor() ?? '#ffffff');
         if ($grayedOut || empty($rgb)) {
             $rgb = Utils::convertToHex('whitesmoke');
         }
 
-        [$foreground, $border] = $this->hexToForegroundAndBorder($rgb);
+        [$foreground, $border] = Utils::hexToForegroundAndBorder($rgb);
 
         if ($grayedOut) {
             $foreground = 'silver';
@@ -1262,7 +1212,7 @@ public function problemBadgeMaybe(
             $rgb = Utils::convertToHex('whitesmoke');
         }
 
-        [$foreground, $border] = $this->hexToForegroundAndBorder($rgb);
+        [$foreground, $border] = Utils::hexToForegroundAndBorder($rgb);
 
         if (!$matrixItem->isCorrect) {
             $foreground = 'silver';

webapp/src/Utils/Utils.php

@@ -290,7 +290,7 @@
      */
     public static function convertToHex(string $color): ?string
     {
-        if (preg_match('/^#[[:xdigit:]]{3,6}$/', $color)) {
+        if (preg_match('/^#[[:xdigit:]]{3}(?:[[:xdigit:]]{3}){0,2}$/', $color)) {
             return $color;
         }
 
@@ -375,7 +375,62 @@
      */
     public static function rgbToHex(array $color): string
     {
-        return "#" . static::componentToHex($color[0]) . static::componentToHex($color[1]) . static::componentToHex($color[2]);
+        $result = "#";
+        for ($i=0; $i<count($color); $i++) {
+            $result .= static::componentToHex($color[$i]);
+        }
+        return $result;
+    }
+
+    public static function relativeLuminance(string $rgb): float
+    {
+        // See https://en.wikipedia.org/wiki/Relative_luminance
+        [$r, $g, $b] = static::parseHexColor($rgb);
+
+        [$lr, $lg, $lb] = [
+            pow($r / 255, 2.4),
+            pow($g / 255, 2.4),
+            pow($b / 255, 2.4),
+        ];
+
+        return 0.2126 * $lr + 0.7152 * $lg + 0.0722 * $lb;
+    }
+
+    public static function apcaContrast(string $fgColor, string $bgColor): float
+    {
+        // Based on WCAG 3.x (https://www.w3.org/TR/wcag-3.0/)
+        $luminanceForeground = static::relativeLuminance($fgColor);
+        $luminanceBackground = static::relativeLuminance($bgColor);
+
+        $contrast = ($luminanceBackground > $luminanceForeground)
+            ? (pow($luminanceBackground, 0.56) - pow($luminanceForeground, 0.57)) * 1.14
+            : (pow($luminanceBackground, 0.65) - pow($luminanceForeground, 0.62)) * 1.14;
+
+        return round($contrast * 100, 2);
+    }
+
+    /**
+     * @return array{string, string}
+     */
+    public static function hexToForegroundAndBorder(string $rgb): array
+    {
+        $background = Utils::parseHexColor($rgb);
+
+        // Pick a border that's a bit darker.
+        // We explicit keep the alpha channel as-is.
+        $darker = $background;
+        $darker[0] = max($darker[0] - 64, 0);
+        $darker[1] = max($darker[1] - 64, 0);
+        $darker[2] = max($darker[2] - 64, 0);
+        $border    = Utils::rgbToHex($darker);
+
+        // Pick the text color with the biggest absolute contrast.
+        $contrastWithWhite = static::apcaContrast('#ffffff', $rgb);
+        $contrastWithBlack = static::apcaContrast('#000000', $rgb);
+
+        $foreground = (abs($contrastWithBlack) > abs($contrastWithWhite)) ? '#000000' : '#ffffff';
+
+        return [$foreground, $border];
     }
 
     /**
@@ -1027,10 +1082,10 @@
     /**
      * Call ob_flush() unless the top-level output buffer does not allow it.
      */
     public static function ob_flush_if_possible(): bool
     {
         $status = ob_get_status();
         if ( empty($status) || ($status['flags'] & PHP_OUTPUT_HANDLER_CLEANABLE) ) {
             return ob_flush();
         }
         return false;

webapp/tests/Unit/Utils/UtilsTest.php

@@ -317,12 +317,17 @@ public function testConvertToHexConvert(): void
         self::assertEquals('#00BFFF', Utils::convertToHex('deep sky blue'));
         self::assertEquals('#FFD700', Utils::convertToHex('GOLD'));
         self::assertEquals('#B8860B', Utils::convertToHex('darkgoldenrod '));
+        self::assertEquals('#aabbcc', Utils::convertToHex('#aabbcc'));
+        self::assertEquals('#aaabbbccc', Utils::convertToHex('#aaabbbccc'));
+        self::assertEquals('#def', Utils::convertToHex('#def'));
+        self::assertEquals('#f1A', Utils::convertToHex('#f1A'));
     }
 
     public function testParseHexColor(): void
     {
         self::assertEquals([255, 255, 255], Utils::parseHexColor('#ffffff'));
         self::assertEquals([0, 0, 0], Utils::parseHexColor('#000000'));
+        self::assertEquals([0, 0, 0], Utils::parseHexColor('#000'));
         self::assertEquals([171, 205, 239], Utils::parseHexColor('#abcdef'));
         self::assertEquals([254, 220, 186], Utils::parseHexColor('#FEDCBA'));
     }
@@ -343,6 +348,34 @@ public function testRgbToHex(): void
         self::assertEquals('#fedcba', Utils::rgbToHex([254, 220, 186]));
     }
 
+    public function testRelativeLuminance(): void
+    {
+        self::assertEquals(0.0, Utils::relativeLuminance("#000000"));
+        self::assertEquals(1.0, Utils::relativeLuminance("#FFFfff"));
+        self::assertEquals(0.00751604342389449, Utils::relativeLuminance("#123"));
+    }
+
+    /**
+     * Test that the APCA contrast function returns the correct data
+     */
+    public function testApcaContrast(): void
+    {
+        self::assertEquals(-114.0, Utils::apcaContrast("#fff", "#000000"));
+        self::assertEquals(-114.0, Utils::apcaContrast("#ffffff", "#000000"));
+        self::assertEquals(-114.0, Utils::apcaContrast("#fffffffff", "#000"));
+        self::assertEquals(114.0, Utils::apcaContrast("#000000", "#ffffff"));
+        self::assertEquals(0.0, Utils::apcaContrast("#fffFFF", "#FFFfff"));
+        self::assertEquals(-0.36, Utils::apcaContrast("#111", "#111"));
+    }
+
+    public function testHexToForegroundAndBorder(): void
+    {
+        self::assertEquals(["#000000", "#bfbd9d"], Utils::hexToForegroundAndBorder("#fffDDD"));
+        self::assertEquals(["#ffffff", "#000000"], Utils::hexToForegroundAndBorder("#000000"));
+        self::assertEquals(["#000000", "#6a7b8c"], Utils::hexToForegroundAndBorder("#ABC"));
+        self::assertEquals(["#000000", "#6a7b8c"], Utils::hexToForegroundAndBorder("#AAABBBCCC"));
+    }
+
     /**
      * Test function that converts colour name to hex notation.
      * Returns null for unknown values.
@@ -351,7 +384,9 @@ public function testConvertToHexUnknown(): void
     {
         self::assertNull(Utils::convertToHex('doesnotexist'));
         self::assertNull(Utils::convertToHex('#aabbccdd'));
-        self::assertNull(Utils::convertToHex('#12346h'));
+        self::assertNull(Utils::convertToHex('#12345h'));
+        self::assertNull(Utils::convertToHex('#1234'));
+        self::assertNull(Utils::convertToHex('#12'));
     }
 
     /**
@@ -770,7 +805,7 @@ public function testSanitizeSvg(): void
                 <a xlink:href="javascript:alert(2)">test 2</a>
                 <a href="#test3">test 3</a>
                 <a xlink:href="#test">test 4</a>
-            
+
                 <a href="data:data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' onload='alert(88)'%3E%3C/svg%3E">test 5</a>
                 <a xlink:href="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' onload='alert(88)'%3E%3C/svg%3E">test 6</a>
                 <use xlink:href="defs.svg#icon-1"/>
@@ -783,7 +818,7 @@ public function testSanitizeSvg(): void
             <this>shouldn't be here</this>
             <script>alert(1);</script>
             <line fill="none" stroke="#000000" stroke-miterlimit="10" x1="541.54" y1="299.573" x2="543.179" y2="536.458"/>
-            
+
             </svg>
             EOF;
         $clean = Utils::sanitizeSvg($dirty);