Make the equalizer sliders stick in the middle around '0' when being dragged. Updates issue #166

src/CMakeLists.txt

@@ -72,6 +72,7 @@ set(CLEMENTINE-SOURCES
     equalizer.cpp
     equalizerslider.cpp
     tracksliderslider.cpp
+    stickyslider.cpp
 )
 
 # Header files that have Q_OBJECT in
@@ -134,6 +135,7 @@ set(CLEMENTINE-MOC-HEADERS
     groupbydialog.h
     equalizer.h
     equalizerslider.h
+    stickyslider.h
 )
 
 # UI files

src/equalizerslider.h

@@ -21,6 +21,7 @@
 
 #include "ui_equalizerslider.h"
 
+// Contains the slider and the label
 class EqualizerSlider : public QWidget {
   Q_OBJECT
 

src/equalizerslider.ui

@@ -33,7 +33,7 @@
       </spacer>
      </item>
      <item>
-      <widget class="QSlider" name="slider">
+      <widget class="StickySlider" name="slider">
        <property name="minimum">
         <number>-100</number>
        </property>
@@ -43,6 +43,12 @@
        <property name="orientation">
         <enum>Qt::Vertical</enum>
        </property>
+       <property name="sticky_center" stdset="0">
+        <number>0</number>
+       </property>
+       <property name="sticky_threshold" stdset="0">
+        <number>10</number>
+       </property>
       </widget>
      </item>
      <item>
@@ -69,6 +75,13 @@
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>StickySlider</class>
+   <extends>QSlider</extends>
+   <header>stickyslider.h</header>
+  </customwidget>
+ </customwidgets>
  <resources/>
  <connections/>
 </ui>

src/stickyslider.cpp

@@ -0,0 +1,36 @@
+/* This file is part of Clementine.
+
+   Clementine 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.
+
+   Clementine 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 Clementine.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "stickyslider.h"
+
+StickySlider::StickySlider(QWidget *parent)
+  : QSlider(parent),
+    sticky_center_(-1),
+    sticky_threshold_(10)
+{
+}
+
+void StickySlider::mouseMoveEvent(QMouseEvent *e) {
+  QSlider::mouseMoveEvent(e);
+
+  if (sticky_center_ == -1)
+    return;
+
+  const int v = value();
+  if (v <= sticky_center_ + sticky_threshold_ &&
+      v >= sticky_center_ - sticky_threshold_)
+    setValue(sticky_center_);
+}

src/stickyslider.h

@@ -0,0 +1,43 @@
+/* This file is part of Clementine.
+
+   Clementine 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.
+
+   Clementine 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 Clementine.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef STICKYSLIDER_H
+#define STICKYSLIDER_H
+
+#include <QSlider>
+
+class StickySlider : public QSlider {
+  Q_OBJECT
+  Q_PROPERTY(int sticky_center READ sticky_center WRITE set_sticky_center);
+  Q_PROPERTY(int sticky_threshold READ sticky_threshold WRITE set_sticky_threshold);
+
+ public:
+  StickySlider(QWidget* parent = 0);
+
+  int sticky_center() const { return sticky_center_; }
+  int sticky_threshold() const { return sticky_threshold_; }
+  void set_sticky_center(int center) { sticky_center_ = center; }
+  void set_sticky_threshold(int threshold) { sticky_threshold_ = threshold; }
+
+ protected:
+  void mouseMoveEvent(QMouseEvent* e);
+
+ private:
+  int sticky_center_;
+  int sticky_threshold_;
+};
+
+#endif // STICKYSLIDER_H