Modified effect parameter handling to improve user experience

This change is to work around a limitation in the Phonon::EffectWidget
class.  This widget only displays sliders for parameters with numeric
values if the variant type of the parameter is QReal and the range is
exactly -1.0 to +1.0; otherwise, a spinbox is displayed. This is
rather inconvenient for many effects, such as the audio equalizer, for
which a slider is a much more natural UI control.

The MMF backend therefore reports the type of numeric parameters to
be QReal, and the range to be -1.0 to +1.0.  Internally, the integer
range for the parameter is stored.  Changes to the parameter value are
converted from the client-side, floating point representation to the
internal, integer representation.

Task-number: QTBUG-4659
Reviewed-by: Espen Riskedal

1 files changed, 72 insertions, 0 deletions

diff --git a/src/3rdparty/phonon/mmf/effectparameter.h b/src/3rdparty/phonon/mmf/effectparameter.h
new file mode 100644
index 0000000..3008159
--- /dev/null
+++ b/src/3rdparty/phonon/mmf/effectparameter.h
@@ -0,0 +1,72 @@
+/*  This file is part of the KDE project.
+
+Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+
+This library is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 2.1 or 3 of the License.
+
+This library 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#ifndef PHONON_MMF_EFFECTPARAMETER_H
+#define PHONON_MMF_EFFECTPARAMETER_H
+
+#include <Phonon/EffectParameter>
+
+QT_BEGIN_NAMESPACE
+
+namespace Phonon
+{
+namespace MMF
+{
+
+/**
+ * @short Parameter value for an audio effect
+ *
+ * The base class is extended in order to work around a shortcoming
+ * in Phonon::EffectWidget.  This widget only displays sliders for
+ * parameters with numeric values if the variant type of the parameter
+ * is QReal and the range is exactly -1.0 to +1.0; otherwise, a
+ * spinbox is used to set numeric parameters.  This is rather
+ * inconvenient for many effects, such as the audio equalizer, for
+ * which a slider is a much more natural UI control.
+ *
+ * For many such parameters, we therefore report the type to be QReal
+ * and the range to be -1.0 to +1.0.  This class stores the actual
+ * integer range for the parameter, and provides the toInternalValue
+ * function for converting between the client-side floating point
+ * value and the internal integer value.
+ */
+class EffectParameter : public Phonon::EffectParameter
+{
+public:
+    EffectParameter();
+    EffectParameter(int parameterId, const QString &name, Hints hints,
+                    const QVariant &defaultValue, const QVariant &min = QVariant(),
+                    const QVariant &max = QVariant(), const QVariantList &values = QVariantList(),
+                    const QString &description = QString());
+
+    void setInternalRange(qint32 min, qint32 max);
+    qint32 toInternalValue(qreal external) const;
+
+private:
+    bool                    m_hasInternalRange;
+    QPair<qint32, qint32>   m_internalRange;
+
+};
+
+}
+}
+
+QT_END_NAMESPACE
+
+#endif
+