Fix icon size issues

src/iconprovider.cpp

@@ -58,8 +58,11 @@ void IconProvider::drop()
 QIcon IconProvider::getIcon(const QString &iconId)
 {
 #if defined(Q_WS_X11) && (QT_VERSION >= QT_VERSION_CHECK(4,6,0))
-  if(m_useSystemTheme)
-    return QIcon::fromTheme(iconId, QIcon(":/Icons/oxygen/"+iconId+".png"));
+  if(m_useSystemTheme) {
+    QIcon icon = QIcon::fromTheme(iconId, QIcon(":/Icons/oxygen/"+iconId+".png"));
+    icon = generateDifferentSizes(icon);
+    return icon;
+  }
 #endif
   return QIcon(":/Icons/oxygen/"+iconId+".png");
 }
@@ -69,6 +72,31 @@ void IconProvider::useSystemIconTheme(bool enable)
 {
   m_useSystemTheme = enable;
 }
+
+QIcon IconProvider::generateDifferentSizes(const QIcon &icon)
+{
+  QIcon new_icon;
+  QList<QSize> required_sizes;
+  required_sizes << QSize(16, 16) << QSize(24, 24);
+  QList<QIcon::Mode> modes;
+  modes << QIcon::Normal << QIcon::Active << QIcon::Selected << QIcon::Disabled;
+  foreach(const QSize& size, required_sizes) {
+    foreach(QIcon::Mode mode, modes) {
+      QPixmap pixoff = icon.pixmap(size, mode, QIcon::Off);
+      if(pixoff.height() > size.height())
+        pixoff = pixoff.scaled(size, Qt::KeepAspectRatio,  Qt::SmoothTransformation);
+      new_icon.addPixmap(pixoff, mode, QIcon::Off);
+      Q_ASSERT(pixoff.height() <= size.height());
+      QPixmap pixon = icon.pixmap(size, mode, QIcon::On);
+      if(pixon.height() > size.height())
+        pixon = pixoff.scaled(size, Qt::KeepAspectRatio,  Qt::SmoothTransformation);
+      new_icon.addPixmap(pixon, mode, QIcon::On);
+      Q_ASSERT(pixon.height() <= size.height());
+    }
+    Q_ASSERT(new_icon.availableSizes().contains(size));
+  }
+  return new_icon;
+}
 #endif
 
 QString IconProvider::getIconPath(const QString &iconId)

src/iconprovider.h

@@ -52,6 +52,9 @@ public:
 public:
   void useSystemIconTheme(bool enable);
 
+private:
+  QIcon generateDifferentSizes(const QIcon& icon);
+
 private:
   bool m_useSystemTheme;
 #endif