--- a
+++ b/GUI/progresswidget/progresswidgetif.h
@@ -0,0 +1,58 @@
+/* Copyright (C) 2015 J.F.Dockes
+ *   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 2 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, write to the
+ *   Free Software Foundation, Inc.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef _PROGRESSWIDGETIF_H_INCLUDED_
+#define _PROGRESSWIDGETIF_H_INCLUDED_
+
+#include <QWidget>
+#include <QString>
+
+// Abstract interface for a volume control.
+class ProgressWidgetIF : public QWidget {
+    Q_OBJECT;
+
+public:
+    ProgressWidgetIF(QWidget *parent = 0)
+        : QWidget(parent) {
+    }
+    virtual ~ProgressWidgetIF() {}
+
+public slots:
+    // All times are in seconds
+
+    virtual void setTotalTime(int value) = 0;
+
+    // Set value and do whatever we do when it changes (emit
+    // signals)
+    virtual void seek(int value) = 0;
+    // Increment/decrement value and do whatever we do when it
+    // changes (emit signals). steps are in units of step_unit (x %)
+    virtual void step(int steps) = 0;
+    virtual void set_step_value_pc(int percent) = 0;
+    virtual void set_step_value_secs(int secs) = 0;
+    // Set-up display, keep quiet
+    virtual void setUi(int value) = 0;
+    virtual void setSkinSuffix(const QString&) {
+    }
+    
+signals:
+    // Emitted when requested position changes, either because the
+    // user acted on the slider, or seek() was called
+    void progressChanged(int);
+};
+
+#endif /* _PROGRESSWIDGETIF_H_INCLUDED_ */