Move PlaylistProxyStyle to it's own file

src/playlist/playlistproxystyle.h

@@ -0,0 +1,53 @@
+/*
+ * Strawberry Music Player
+ * This file was part of Clementine.
+ * Copyright 2010, David Sansome <me@davidsansome.com>
+ * Copyright 2018-2023, 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/>.
+ *
+ */
+
+#ifndef PLAYLISTPROXYSTYLE_H
+#define PLAYLISTPROXYSTYLE_H
+
+#include "config.h"
+
+#include <QProxyStyle>
+#include <QCommonStyle>
+#include <QString>
+
+#include "core/scoped_ptr.h"
+
+class QPainter;
+
+// This proxy style works around a bug/feature introduced in Qt 4.7's QGtkStyle
+// that uses Gtk to paint row backgrounds, ignoring any custom brush or palette the caller set in the QStyleOption.
+// That breaks our currently playing track animation, which relies on the background painted by Qt to be transparent.
+// This proxy style uses QCommonStyle to paint the affected elements.
+
+class PlaylistProxyStyle : public QProxyStyle {
+  Q_OBJECT
+
+ public:
+  explicit PlaylistProxyStyle(const QString &style);
+
+  void drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const override;
+  void drawPrimitive(PrimitiveElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const override;
+
+ private:
+  ScopedPtr<QCommonStyle> common_style_;
+};
+
+#endif  // PLAYLISTPROXYSTYLE_H