Split utilities functions into separate files

src/utilities/colorutils.cpp

@@ -0,0 +1,41 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2018-2021, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <QString>
+#include <QColor>
+
+#include "colorutils.h"
+
+namespace Utilities {
+
+QString ColorToRgba(const QColor &c) {
+
+  return QString("rgba(%1, %2, %3, %4)")
+      .arg(c.red())
+      .arg(c.green())
+      .arg(c.blue())
+      .arg(c.alpha());
+
+}
+
+bool IsColorDark(const QColor &color) {
+  return ((30 * color.red() + 59 * color.green() + 11 * color.blue()) / 100) <= 130;
+}
+
+}  // namespace Utilities