diff -r 89e065397ea6 -r e24348a560a6 demos/spectrum/app/spectrograph.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demos/spectrum/app/spectrograph.cpp	Fri Jun 11 14:24:45 2010 +0300
@@ -0,0 +1,242 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "spectrograph.h"
+#include <QPainter>
+#include <QMouseEvent>
+#include <QDebug>
+#include <QTimerEvent>
+
+const int NullTimerId = -1;
+const int NullIndex = -1;
+const int BarSelectionInterval = 2000;
+
+Spectrograph::Spectrograph(QWidget *parent)
+    :   QWidget(parent)
+    ,   m_barSelected(NullIndex)
+    ,   m_timerId(NullTimerId)
+    ,   m_lowFreq(0.0)
+    ,   m_highFreq(0.0)
+{
+    setMinimumHeight(100);
+}
+
+Spectrograph::~Spectrograph()
+{
+
+}
+
+void Spectrograph::setParams(int numBars, qreal lowFreq, qreal highFreq)
+{
+    Q_ASSERT(numBars > 0);
+    Q_ASSERT(highFreq > lowFreq);
+    m_bars.resize(numBars);
+    m_lowFreq = lowFreq;
+    m_highFreq = highFreq;
+    updateBars();
+}
+
+void Spectrograph::timerEvent(QTimerEvent *event)
+{
+    Q_ASSERT(event->timerId() == m_timerId);
+    Q_UNUSED(event) // suppress warnings in release builds
+    killTimer(m_timerId);
+    m_timerId = NullTimerId;
+    m_barSelected = NullIndex;
+    update();
+}
+
+void Spectrograph::paintEvent(QPaintEvent *event)
+{
+    Q_UNUSED(event)
+
+    QPainter painter(this);
+    painter.fillRect(rect(), Qt::black);
+
+    const int numBars = m_bars.count();
+
+    // Highlight region of selected bar
+    if (m_barSelected != NullIndex && numBars) {
+        QRect regionRect = rect();
+        regionRect.setLeft(m_barSelected * rect().width() / numBars);
+        regionRect.setWidth(rect().width() / numBars);
+        QColor regionColor(202, 202, 64);
+        painter.setBrush(Qt::DiagCrossPattern);
+        painter.fillRect(regionRect, regionColor);
+        painter.setBrush(Qt::NoBrush);
+    }
+
+    QColor barColor(51, 204, 102);
+    QColor clipColor(255, 255, 0);
+
+    // Draw the outline
+    const QColor gridColor = barColor.darker();
+    QPen gridPen(gridColor);
+    painter.setPen(gridPen);
+    painter.drawLine(rect().topLeft(), rect().topRight());
+    painter.drawLine(rect().topRight(), rect().bottomRight());
+    painter.drawLine(rect().bottomRight(), rect().bottomLeft());
+    painter.drawLine(rect().bottomLeft(), rect().topLeft());
+
+    QVector<qreal> dashes;
+    dashes << 2 << 2;
+    gridPen.setDashPattern(dashes);
+    painter.setPen(gridPen);
+
+    // Draw vertical lines between bars
+    if (numBars) {
+        const int numHorizontalSections = numBars;
+        QLine line(rect().topLeft(), rect().bottomLeft());
+        for (int i=1; i<numHorizontalSections; ++i) {
+            line.translate(rect().width()/numHorizontalSections, 0);
+            painter.drawLine(line);
+        }
+    }
+
+    // Draw horizontal lines
+    const int numVerticalSections = 10;
+    QLine line(rect().topLeft(), rect().topRight());
+    for (int i=1; i<numVerticalSections; ++i) {
+        line.translate(0, rect().height()/numVerticalSections);
+        painter.drawLine(line);
+    }
+
+    barColor = barColor.lighter();
+    barColor.setAlphaF(0.75);
+    clipColor.setAlphaF(0.75);
+
+    // Draw the bars
+    if (numBars) {
+        // Calculate width of bars and gaps
+        const int widgetWidth = rect().width();
+        const int barPlusGapWidth = widgetWidth / numBars;
+        const int barWidth = 0.8 * barPlusGapWidth;
+        const int gapWidth = barPlusGapWidth - barWidth;
+        const int paddingWidth = widgetWidth - numBars * (barWidth + gapWidth);
+        const int leftPaddingWidth = (paddingWidth + gapWidth) / 2;
+        const int barHeight = rect().height() - 2 * gapWidth;
+
+        for (int i=0; i<numBars; ++i) {
+            const qreal value = m_bars[i].value;
+            Q_ASSERT(value >= 0.0 && value <= 1.0);
+            QRect bar = rect();
+            bar.setLeft(rect().left() + leftPaddingWidth + (i * (gapWidth + barWidth)));
+            bar.setWidth(barWidth);
+            bar.setTop(rect().top() + gapWidth + (1.0 - value) * barHeight);
+            bar.setBottom(rect().bottom() - gapWidth);
+
+            QColor color = barColor;
+            if (m_bars[i].clipped)
+                color = clipColor;
+
+            painter.fillRect(bar, color);
+        }
+    }
+}
+
+void Spectrograph::mousePressEvent(QMouseEvent *event)
+{
+    const QPoint pos = event->pos();
+    const int index = m_bars.count() * (pos.x() - rect().left()) / rect().width();
+    selectBar(index);
+}
+
+void Spectrograph::reset()
+{
+    m_spectrum.reset();
+    spectrumChanged(m_spectrum);
+}
+
+void Spectrograph::spectrumChanged(const FrequencySpectrum &spectrum)
+{
+    m_spectrum = spectrum;
+    updateBars();
+}
+
+int Spectrograph::barIndex(qreal frequency) const
+{
+    Q_ASSERT(frequency >= m_lowFreq && frequency < m_highFreq);
+    const qreal bandWidth = (m_highFreq - m_lowFreq) / m_bars.count();
+    const int index = (frequency - m_lowFreq) / bandWidth;
+    if(index <0 || index >= m_bars.count())
+        Q_ASSERT(false);
+    return index;
+}
+
+QPair<qreal, qreal> Spectrograph::barRange(int index) const
+{
+    Q_ASSERT(index >= 0 && index < m_bars.count());
+    const qreal bandWidth = (m_highFreq - m_lowFreq) / m_bars.count();
+    return QPair<qreal, qreal>(index * bandWidth, (index+1) * bandWidth);
+}
+
+void Spectrograph::updateBars()
+{
+    m_bars.fill(Bar());
+    FrequencySpectrum::const_iterator i = m_spectrum.begin();
+    const FrequencySpectrum::const_iterator end = m_spectrum.end();
+    for ( ; i != end; ++i) {
+        const FrequencySpectrum::Element e = *i;
+        if (e.frequency >= m_lowFreq && e.frequency < m_highFreq) {
+            Bar &bar = m_bars[barIndex(e.frequency)];
+            bar.value = qMax(bar.value, e.amplitude);
+            bar.clipped |= e.clipped;
+        }
+    }
+    update();
+}
+
+void Spectrograph::selectBar(int index) {
+    const QPair<qreal, qreal> frequencyRange = barRange(index);
+    const QString message = QString("%1 - %2 Hz")
+                                .arg(frequencyRange.first)
+                                .arg(frequencyRange.second);
+    emit infoMessage(message, BarSelectionInterval);
+
+    if (NullTimerId != m_timerId)
+        killTimer(m_timerId);
+    m_timerId = startTimer(BarSelectionInterval);
+
+    m_barSelected = index;
+    update();
+}
+
+