feat(theming): Separate background and primary color

While the primary color is intended to highlight elements,
it can not always be used as the background color.
So now primary is independent from background a user set,
the background color is, if not set directly, calculated as the mean color
of the background image. That color is then used as a fallback if the
background image could not be loaded and for calculating the color of the text used on the app menu and dashboard (they render directly on the background).

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

1 files changed, 16 insertions, 28 deletions

diff --git a/apps/theming/lib/Themes/CommonThemeTrait.php b/apps/theming/lib/Themes/CommonThemeTrait.php
index cf2427e823e..6d74a7bcdfc 100644
--- a/apps/theming/lib/Themes/CommonThemeTrait.php
+++ b/apps/theming/lib/Themes/CommonThemeTrait.php
@@ -130,49 +130,37 @@ trait CommonThemeTrait {
 		if ($user !== null
 			&& !$this->themingDefaults->isUserThemingDisabled()
 			&& $this->appManager->isEnabledForUser(Application::APP_ID)) {
-			$adminBackgroundDeleted = $this->config->getAppValue(Application::APP_ID, 'backgroundMime', '') === 'backgroundColor';
 			$backgroundImage = $this->config->getUserValue($user->getUID(), Application::APP_ID, 'background_image', BackgroundService::BACKGROUND_DEFAULT);
+			$backgroundColor = $this->config->getUserValue($user->getUID(), Application::APP_ID, 'background_color', $this->themingDefaults->getColorPrimary());
+
 			$currentVersion = (int)$this->config->getUserValue($user->getUID(), Application::APP_ID, 'userCacheBuster', '0');
-			$isPrimaryBright = $this->util->invertTextColor($this->primaryColor);
+			$isBackgroundBright = $this->util->invertTextColor($backgroundColor);
+			$backgroundTextColor = $this->util->invertTextColor($backgroundColor) ? '#000000' : '#ffffff';
+
+			$variables = [
+				'--color-background-plain' => $backgroundColor,
+				'--color-background-plain-text' => $backgroundTextColor,
+				'--background-image-invert-if-bright' => $isBackgroundBright ? 'invert(100%)' : 'no',
+			];
 
 			// The user removed the background
 			if ($backgroundImage === BackgroundService::BACKGROUND_DISABLED) {
-				return [
-					// Might be defined already by admin theming, needs to be overridden
-					'--image-background' => 'none',
-					'--color-background-plain' => $this->primaryColor,
-					// If no background image is set, we need to check against the shown primary colour
-					'--background-image-invert-if-bright' => $isPrimaryBright ? 'invert(100%)' : 'no',
-				];
+				// Might be defined already by admin theming, needs to be overridden
+				$variables['--image-background'] = 'none';
 			}
 
 			// The user uploaded a custom background
 			if ($backgroundImage === BackgroundService::BACKGROUND_CUSTOM) {
 				$cacheBuster = substr(sha1($user->getUID() . '_' . $currentVersion), 0, 8);
-				return [
-					'--image-background' => "url('" . $this->urlGenerator->linkToRouteAbsolute('theming.userTheme.getBackground') . "?v=$cacheBuster')",
-					'--color-background-plain' => $this->themingDefaults->getColorPrimary(),
-					'--background-image-invert-if-bright' => $isPrimaryBright ? 'invert(100%)' : 'no',
-				];
-			}
-
-			// The user is using the default background and admin removed the background image
-			if ($backgroundImage === BackgroundService::BACKGROUND_DEFAULT && $adminBackgroundDeleted) {
-				return [
-					// --image-background is not defined in this case
-					'--color-background-plain' => $this->primaryColor,
-					'--background-image-invert-if-bright' => $isPrimaryBright ? 'invert(100%)' : 'no',
-				];
+				$variables['--image-background'] = "url('" . $this->urlGenerator->linkToRouteAbsolute('theming.userTheme.getBackground') . "?v=$cacheBuster')";
 			}
 
 			// The user picked a shipped background
 			if (isset(BackgroundService::SHIPPED_BACKGROUNDS[$backgroundImage])) {
-				return [
-					'--image-background' => "url('" . $this->urlGenerator->linkTo(Application::APP_ID, "img/background/$backgroundImage") . "')",
-					'--color-background-plain' => $this->primaryColor,
-					'--background-image-invert-if-bright' => BackgroundService::SHIPPED_BACKGROUNDS[$backgroundImage]['theming'] ?? null === BackgroundService::THEMING_MODE_DARK ? 'invert(100%)' : 'no',
-				];
+				$variables['--image-background'] = "url('" . $this->urlGenerator->linkTo(Application::APP_ID, "img/background/$backgroundImage") . "')";
 			}
+
+			return $variables;
 		}
 
 		return [];