Theming: Colorize checkboxes depending on luminance

apps/theming/lib/controller/themingcontroller.php

@@ -214,6 +214,7 @@ class ThemingController extends Controller {
 		$cacheBusterValue = $this->config->getAppValue('theming', 'cachebuster', '0');
 		$responseCss = '';
 		$color = $this->config->getAppValue($this->appName, 'color');
+		$elementColor = Util::elementColor($color);
 		if($color !== '') {
 			$responseCss .= sprintf(
 				'#body-user #header,#body-settings #header,#body-public #header,#body-login,.searchbox input[type="search"]:focus,.searchbox input[type="search"]:active,.searchbox input[type="search"]:valid {background-color: %s}',
@@ -221,11 +222,11 @@ class ThemingController extends Controller {
 			);
 			$responseCss .= sprintf('
 				input[type="checkbox"].checkbox:checked + label:before {
-					background-image:url(/core/img/actions/checkmark-white.svg);
+					background-image:url(\'' . \OC::$WEBROOT . '/core/img/actions/checkmark-white.svg\');
 					background-color: %s; background-position: center center; background-size:contain;
 					width:12px; height:12px; padding:0; margin:1px 6px 7px 2px;
         		}',
-				$color
+				$elementColor
 			);
 		}
 		$logo = $this->config->getAppValue($this->appName, 'logoMime');

apps/theming/lib/util.php

@@ -38,6 +38,21 @@ class Util {
 		}
 	}
 
+	/**
+	 * get color for on-page elements:
+	 * theme color by default, grey if theme color is to bright
+	 * @param $color
+	 * @return string
+	 */
+	public static function elementColor($color) {
+		$l = self::calculateLuminance($color);
+		if($l>0.8) {
+			return '#969696';
+		} else {
+			return $color;
+		}
+	}
+
 	/**
 	 * @param string $color rgb color value
 	 * @return float

apps/theming/tests/lib/UtilTest.php

@@ -65,4 +65,14 @@ class UtilTest extends TestCase {
 		$invert = Util::invertTextColor('');
 		$this->assertEquals(false, $invert);
 	}
+
+	public function testElementColorDefault() {
+		$elementColor = Util::elementColor("#000000");
+		$this->assertEquals('#000000', $elementColor);
+	}
+
+	public function testElementColorOnBrightBackground() {
+		$elementColor = Util::elementColor('#ffffff');
+		$this->assertEquals('#969696', $elementColor);
+	}
 }