Add DpiScaler for fixed pixel sizes conversion

src/libtomahawk/CMakeLists.txt

@@ -101,6 +101,7 @@ set( libGuiSources
     resolvers/JSResolverHelper.cpp
     resolvers/ScriptEngine.cpp
 
+    utils/DpiScaler.cpp
     utils/ImageRegistry.cpp
     utils/WidgetDragFilter.cpp
     utils/XspfGenerator.cpp

src/libtomahawk/utils/DpiScaler.cpp

@@ -0,0 +1,62 @@
+/* === This file is part of Tomahawk Player - <http://tomahawk-player.org> ===
+ *
+ *   Copyright 2013, Teo Mrnjavac <teo@kde.org>
+ *
+ *   Tomahawk 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.
+ *
+ *   Tomahawk 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 Tomahawk. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "DpiScaler.h"
+
+
+namespace TomahawkUtils
+{
+
+
+DpiScaler::DpiScaler( const QPaintDevice* that )
+    : that( that )
+{
+}
+
+
+QSize
+DpiScaler::scaled( int w, int h ) const
+{
+    float ratioX = that->logicalDpiX() / 100.0;
+    float ratioY = that->logicalDpiY() / 100.0;
+    return QSize( qRound( w * ratioX ), qRound( h * ratioY ) );
+}
+
+
+QSize
+DpiScaler::scaled( const QSize& size ) const
+{
+    return scaled( size.width(), size.height() );
+}
+
+
+int
+DpiScaler::scaledX( int x ) const
+{
+    return scaled( x, 0 ).width();
+}
+
+
+int
+DpiScaler::scaledY( int y ) const
+{
+    return scaled( 0, y ).height();
+}
+
+
+}

src/libtomahawk/utils/DpiScaler.h

@@ -0,0 +1,51 @@
+/* === This file is part of Tomahawk Player - <http://tomahawk-player.org> ===
+ *
+ *   Copyright 2013, Teo Mrnjavac <teo@kde.org>
+ *
+ *   Tomahawk 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.
+ *
+ *   Tomahawk 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 Tomahawk. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DPISCALER_H
+#define DPISCALER_H
+
+#include "DllMacro.h"
+
+#include <QPaintDevice>
+#include <QSize>
+
+namespace TomahawkUtils
+{
+
+/**
+ * @brief The DpiScaler class provides some convenience methods to recompute fixed pixel sizes
+ * into values suitable for different environment DPI settings.
+ * Usage:
+ * class Foo : public QWidget, private TomahawkUtils::DpiScaler {...};
+ */
+class DLLEXPORT DpiScaler
+{
+public:
+    DpiScaler( const QPaintDevice* that );
+    QSize scaled( int w, int h ) const;
+    QSize scaled( const QSize& size ) const;
+    int scaledX( int x ) const;
+    int scaledY( int y ) const;
+
+private:
+    const QPaintDevice* that;
+};
+
+}
+
+#endif // DPISCALER_H