Added a PixmapSlider class and changed Slider to inherit from it.

PixmapSlider is a subclass of QAbstractSlider.
It is independent of Skin.cpp. Slider is now only a wrapper to update the
QPixmaps on a skin change.
removed a workaround from equalizerwidget, that was necessary for the previous
implementation.
2-3 one line fixes I don't remember

src/widgets/pixmapslider.cpp

@@ -0,0 +1,195 @@
+/**
+ *  This file is a part of Promoe, an XMMS2 Client
+ *
+ *  Copyright (C) 2008 Thomas Frauendorfer
+ *
+ *  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.
+ */
+
+#include "pixmapslider.h"
+
+#include <QPixmap>
+#include <QStyle>
+#include <QPainter>
+#include <QPaintEvent>
+#include <QMouseEvent>
+
+PixmapSlider::PixmapSlider (QWidget *parent) : QAbstractSlider (parent)
+{
+	setSliderDown (false);
+}
+
+void
+PixmapSlider::setBackground (const QPixmap &pixmap)
+{
+	QPixmapList list;
+	list.append (pixmap);
+	setBackground (list);
+}
+
+void
+PixmapSlider::setBackground (const QPixmapList &list)
+{
+	m_backgrounds = list;
+	m_background_index = -1;
+}
+
+void
+PixmapSlider::setSliders (QPixmap normal, QPixmap pressed)
+{
+	m_normal = normal;
+	m_pressed = pressed;
+}
+
+void
+PixmapSlider::mouseMoveEvent (QMouseEvent *event)
+{
+	if (!isSliderDown ()) {
+		event->ignore ();
+		return;
+	}
+
+	int val = sliderMovePosition (event);
+
+	if (val == value ()) {
+		return;
+	}
+	QAbstractSlider::setValue (val);
+}
+
+void
+PixmapSlider::mousePressEvent (QMouseEvent *event)
+{
+	if (event->button () != Qt::LeftButton) {
+		event->ignore ();
+		return;
+	}
+
+	setSliderDown (true);
+
+	int val = sliderMovePosition (event);
+
+	if (val == value ()) {
+		return;
+	}
+	QAbstractSlider::setValue (val);
+
+	update ();
+}
+
+void
+PixmapSlider::mouseReleaseEvent (QMouseEvent *event)
+{
+	if (event->button () != Qt::LeftButton) {
+		event->ignore ();
+		return;
+	}
+
+	int val = sliderMovePosition (event);
+
+	QAbstractSlider::setValue (val);
+
+	setSliderDown (false);
+
+	update ();
+}
+
+int
+PixmapSlider::sliderMovePosition (QMouseEvent *event)
+{
+	if (orientation () == Qt::Vertical) {
+		return sliderValueFromPosition (event->y() - m_pressed.height () /2);
+	} else {
+		return sliderValueFromPosition (event->x() - m_pressed.width () /2);
+	}
+
+}
+
+void
+PixmapSlider::setValue (int val)
+{
+	if (isSliderDown ()){
+		return;
+	}
+	QAbstractSlider::setValue (val);
+}
+
+void
+PixmapSlider::paintEvent (QPaintEvent *event)
+{
+	QPainter p;
+	p.begin (this);
+	// draw background
+	if (!m_backgrounds.isEmpty ()) {
+		int bg_idx = backgroundIndex ();
+		QPixmap bg = m_backgrounds[bg_idx];
+		// only redraw the complete background, if the index changed
+		if (bg_idx == m_background_index) {
+			p.drawPixmap (event->rect (), bg, bg.rect ());
+		} else {
+			m_background_index = bg_idx;
+			p.drawPixmap (rect (), bg, bg.rect ());
+		}
+	}
+	// draw slider
+	QPixmap *slider = isSliderDown () ? &m_pressed : &m_normal;
+	QRect rect (slider->rect ());
+	if (orientation () == Qt::Vertical) {
+		rect.moveTop (sliderPositionFromValue ());
+		rect.moveLeft (1);
+	} else {
+		rect.moveLeft (sliderPositionFromValue ());
+		rect.moveTop (1);
+	}
+	p.drawPixmap (rect , *slider, slider->rect ());
+	p.end ();
+}
+
+int
+PixmapSlider::sliderPositionFromValue ()
+{
+	int span;
+	if (orientation () == Qt::Vertical) {
+		span = height () - m_normal.height ();
+	} else {
+		span = width () - m_normal.width ();
+	}
+
+    return QStyle::sliderPositionFromValue (minimum (), maximum (),
+	                                        sliderPosition (), span,
+											invertedAppearance ());
+}
+
+int
+PixmapSlider::sliderValueFromPosition (int pos)
+{
+	int span;
+	if (orientation () == Qt::Vertical) {
+		span = height () - m_normal.height ();
+	} else {
+		span = width () - m_normal.width ();
+	}
+
+	return  QStyle::sliderValueFromPosition (minimum (), maximum (), pos,
+	                                         span, invertedAppearance ());
+}
+
+int
+PixmapSlider::backgroundIndex ()
+{
+	if (m_backgrounds.isEmpty ()) {
+		return -1;
+	}
+
+	return QStyle::sliderPositionFromValue (minimum (), maximum (),
+	                                        sliderPosition (),
+	                                        m_backgrounds.size () - 1, false);
+}

src/widgets/pixmapslider.h

@@ -0,0 +1,69 @@
+/**
+ *  This file is a part of Promoe, an XMMS2 CLient
+ *
+ *  Copyright (C) 2008 Thomas Frauendorfer
+ *
+ *  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.
+ */
+
+#ifndef __PIXMAPSLIDER_H__
+#define __PIXMAPSLIDER_H__
+
+#include <QAbstractSlider>
+#include <QList>
+
+class QWidget;
+class QPixmap;
+class QPaintEvent;
+class QMouseEvent;
+
+typedef QList<QPixmap> QPixmapList;
+
+class PixmapSlider : public QAbstractSlider
+{
+	Q_OBJECT
+	public:
+		PixmapSlider (QWidget *parent);
+		~PixmapSlider () {}
+
+		void setValue (int val);
+
+		void setBackground (const QPixmap &);
+		void setBackground (const QPixmapList &);
+		QPixmapList backgrounds () const { return m_backgrounds; }
+
+		void setSliders (QPixmap normal, QPixmap pressed = QPixmap ());
+		QPixmap normalSlider () const { return m_normal; }
+		QPixmap pressedSlider () const { return m_pressed; }
+
+	protected slots:
+		void paintEvent (QPaintEvent *event);
+
+		void mouseMoveEvent (QMouseEvent *);
+		void mousePressEvent (QMouseEvent *);
+		void mouseReleaseEvent (QMouseEvent *);
+
+	protected:
+		int sliderMovePosition (QMouseEvent *);
+
+		int sliderPositionFromValue ();
+		int sliderValueFromPosition (int pos);
+		int backgroundIndex ();
+
+	private:
+		QPixmapList m_backgrounds;
+		QPixmap m_normal;
+		QPixmap m_pressed;
+
+		int m_background_index;
+};
+
+#endif

src/widgets/widgets.pri

@@ -1,6 +1,8 @@
-HEADERS += pixmapbutton.h
+HEADERS += pixmapbutton.h \
+           pixmapslider.h
 
-SOURCES += pixmapbutton.cpp
+SOURCES += pixmapbutton.cpp \
+           pixmapslider.cpp
 
 INCLUDEPATH += $$PWD
 DEPENDPATH += $$PWD