aboutdialog: support patreon list

app/dialog/about/scrollinglabel.h

@@ -0,0 +1,71 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2021 Olive Team
+
+  This program 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.
+
+  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+***/
+
+#ifndef SCROLLINGLABEL_H
+#define SCROLLINGLABEL_H
+
+#include <QTimer>
+#include <QWidget>
+
+namespace olive {
+
+class ScrollingLabel : public QWidget
+{
+  Q_OBJECT
+public:
+  ScrollingLabel(QWidget* parent = nullptr);
+  ScrollingLabel(const QStringList& text, QWidget* parent = nullptr);
+
+  void SetText(const QStringList& text);
+
+  void StartAnimating()
+  {
+    timer_.start();
+  }
+
+  void StopAnimating()
+  {
+    timer_.stop();
+  }
+
+protected:
+  virtual void paintEvent(QPaintEvent* e) override;
+
+private:
+  static void SetOpacityOfScanLine(uchar* scan_line, int width, int channels, double mul);
+
+  static const int kMinLineHeight;
+
+  QStringList text_;
+
+  int text_height_;
+
+  QTimer timer_;
+
+  int animate_;
+
+private slots:
+  void AnimationUpdate();
+
+};
+
+}
+
+#endif // SCROLLINGLABEL_H