Normalize potmeter widget values to [0.0, 1.0] instead of [0.0, 127.0].

This is another step towards getting rid of MIDI assumptions that are baked into
the widget system.

* Control parameter space for potmeters is now [0.0, 1.0] instead of [0.0,
  127.0].
* Non-linearity of parameter space (64 being the center value) now only applies
  to MIDI, not widgets.
* Fix all potmeter-style widgets to use [0.0, 1.0] for parameter values.

9 files changed, 72 insertions, 51 deletions

diff --git a/src/widget/knobeventhandler.h b/src/widget/knobeventhandler.h
index f638f5a87e..61a11951be 100644
--- a/src/widget/knobeventhandler.h
+++ b/src/widget/knobeventhandler.h
@@ -31,13 +31,12 @@ class KnobEventHandler {
             }
 
             double value = pWidget->getValue();
-            value += dist;
+            // For legacy (MIDI) reasons this is tuned to 127.
+            value += dist / 127.0;
             QCursor::setPos(m_startPos);
 
-            if (value > 127.0)
-                value = 127.0;
-            else if (value < 0.0)
-                value = 0.0;
+            // Clamp to [0.0, 1.0]
+            value = math_max(0.0, math_min(1.0, value));
 
             pWidget->setValue(value);
             emit(pWidget->valueChangedLeftDown(value));
@@ -80,11 +79,12 @@ class KnobEventHandler {
     }
 
     void wheelEvent(T* pWidget, QWheelEvent* e) {
-        double wheelDirection = e->delta() / 120.;
+        // For legacy (MIDI) reasons this is tuned to 127.
+        double wheelDirection = e->delta() / (120.0 * 127.0);
         double newValue = pWidget->getValue() + wheelDirection;
 
-        // Clamp to [0.0, 127.0]
-        newValue = math_max(0.0, math_min(127.0, newValue));
+        // Clamp to [0.0, 1.0]
+        newValue = math_max(0.0, math_min(1.0, newValue));
 
         pWidget->updateValue(newValue);
         e->accept();
diff --git a/src/widget/wdisplay.cpp b/src/widget/wdisplay.cpp
index 0d8bbf9cb5..7c325e598a 100644
--- a/src/widget/wdisplay.cpp
+++ b/src/widget/wdisplay.cpp
@@ -108,8 +108,7 @@ void WDisplay::setPixmap(QVector<PaintablePointer>* pPixmaps, int iPos,
 }
 
 int WDisplay::getActivePixmapIndex() const {
-    return static_cast<int>(
-        m_value * static_cast<double>(m_pixmaps.size()) / 128.0);
+    return static_cast<int>(m_value * m_pixmaps.size());
 }
 
 void WDisplay::paintEvent(QPaintEvent* ) {
diff --git a/src/widget/wknob.cpp b/src/widget/wknob.cpp
index e379643f29..d2b4f306ea 100644
--- a/src/widget/wknob.cpp
+++ b/src/widget/wknob.cpp
@@ -29,9 +29,7 @@ WKnob::~WKnob() {
 }
 
 int WKnob::getActivePixmapIndex() const {
-    // TODO(rryan): Ew.
-    int iNoPos = numPixmaps();
-    return (int)(((m_value-64.)*(((float)iNoPos-1.)/127.))+((float)iNoPos/2.));
+    return static_cast<int>(m_value * numPixmaps());
 }
 
 void WKnob::mouseMoveEvent(QMouseEvent* e) {
diff --git a/src/widget/wknobcomposed.cpp b/src/widget/wknobcomposed.cpp
index e1ef2d32f8..ef7e865ba1 100644
--- a/src/widget/wknobcomposed.cpp
+++ b/src/widget/wknobcomposed.cpp
@@ -69,8 +69,8 @@ void WKnobComposed::paintEvent(QPaintEvent* e) {
     if (!m_pKnob.isNull() && !m_pKnob->isNull()) {
         p.translate(width() / 2.0, height() / 2.0);
 
-        // Value is now in the range [0, 1].
-        double value = getValue() / 127.0;
+        // Value is in the range [0, 1].
+        double value = getValue();
 
         double angle = m_dMinAngle + (m_dMaxAngle - m_dMinAngle) * value;
         p.rotate(angle);
diff --git a/src/widget/woverview.cpp b/src/widget/woverview.cpp
index e7ae137379..f17f607932 100644
--- a/src/widget/woverview.cpp
+++ b/src/widget/woverview.cpp
@@ -120,14 +120,14 @@ void WOverview::setup(QDomNode node) {
     //qDebug() << "WOverview : m_markRanges" << m_markRanges.size();
 }
 
-void WOverview::setValue(double fValue) {
+void WOverview::setValue(double dValue) {
     if (!m_bDrag)
     {
         // Calculate handle position
-        int iPos = valueToPosition(fValue);
+        int iPos = valueToPosition(dValue);
         if (iPos != m_iPos) {
             m_iPos = iPos;
-            //qDebug() << "WOverview::setValue" << fValue << ">>" << m_iPos;
+            //qDebug() << "WOverview::setValue" << dValue << ">>" << m_iPos;
             update();
         }
     }
@@ -247,14 +247,14 @@ void WOverview::mouseMoveEvent(QMouseEvent* e) {
 void WOverview::mouseReleaseEvent(QMouseEvent* e) {
     mouseMoveEvent(e);
 
-    float fValue = positionToValue(m_iPos);
+    double dValue = positionToValue(m_iPos);
 
-    //qDebug() << "WOverview::mouseReleaseEvent" << e->pos() << m_iPos << ">>" << fValue;
+    //qDebug() << "WOverview::mouseReleaseEvent" << e->pos() << m_iPos << ">>" << dValue;
 
     if (e->button() == Qt::RightButton) {
-        emit(valueChangedRightUp(fValue));
+        emit(valueChangedRightUp(dValue));
     } else {
-        emit(valueChangedLeftUp(fValue));
+        emit(valueChangedLeftUp(dValue));
     }
     m_bDrag = false;
 }
@@ -466,9 +466,21 @@ void WOverview::paintText(const QString &text, QPainter *painter) {
 }
 
 void WOverview::resizeEvent(QResizeEvent *) {
-    //Those coeficient map position from [0;width-1] to value [14;114]
-    m_a = (float)((width()-1))/( 114.f - 14.f);
-    m_b = 14.f * m_a;
+    // Play-position potmeters range from -0.14 to 1.14. This is to give VC and
+    // MIDI control access to the pre-roll area.
+    // TODO(rryan): get these limits from the CO itself.
+    const double kMaxPlayposRange = 1.14;
+    const double kMinPlayposRange = -0.14;
+
+    // Values of zero and one in normalized space.
+    const double zero = (0.0 - kMinPlayposRange) / (kMaxPlayposRange - kMinPlayposRange);
+    const double one = (1.0 - kMinPlayposRange) / (kMaxPlayposRange - kMinPlayposRange);
+
+    // These coeficients convert between widget space and normalized value
+    // space.
+    m_a = (width() - 1) / (one - zero);
+    m_b = zero * m_a;
+
     m_waveformImageScaled = QImage();
     m_diffGain = 0;
 }
diff --git a/src/widget/woverview.h b/src/widget/woverview.h
index e5ffd81798..dd94276c44 100644
--- a/src/widget/woverview.h
+++ b/src/widget/woverview.h
@@ -84,11 +84,11 @@ class WOverview : public WWidget {
     // Append the waveform overview pixmap according to available data in waveform
     virtual bool drawNextPixmapPart() = 0;
     void paintText(const QString &text, QPainter *painter);
-    inline int valueToPosition(float value) const {
-        return static_cast<int>(m_a * value - m_b + 0.5);
+    inline int valueToPosition(double value) const {
+        return static_cast<int>(m_a * value - m_b);
     }
     inline double positionToValue(int position) const {
-        return (static_cast<float>(position) + m_b) / m_a;
+        return (static_cast<double>(position) + m_b) / m_a;
     }
 
     const QString m_group;
@@ -116,8 +116,8 @@ class WOverview : public WWidget {
     std::vector<WaveformMarkRange> m_markRanges;
 
     // Coefficient value-position linear transposition
-    float m_a;
-    float m_b;
+    double m_a;
+    double m_b;
 
     double m_dAnalyserProgress;
     bool m_bAnalyserFinalizing;
diff --git a/src/widget/wslidercomposed.cpp b/src/widget/wslidercomposed.cpp
index 189aa3b426..ced64e0506 100644
--- a/src/widget/wslidercomposed.cpp
+++ b/src/widget/wslidercomposed.cpp
@@ -101,16 +101,19 @@ void WSliderComposed::mouseMoveEvent(QMouseEvent * e) {
 
         int sliderLength = m_bHorizontal ? width() : height();
 
+        // Clamp to the range [0, sliderLength - m_iHandleLength].
         if (m_iPos > (sliderLength - m_iHandleLength)) {
             m_iPos = sliderLength - m_iHandleLength;
         } else if (m_iPos < 0) {
             m_iPos = 0;
         }
 
-        // value ranges from 0 to 127
-        m_value = (double)m_iPos * (127. / (double)(sliderLength - m_iHandleLength));
+        // Divide by (sliderLength - m_iHandleLength) to produce a normalized
+        // value in the range of [0.0, 1.0].  1.0
+        m_value = static_cast<double>(m_iPos) /
+                static_cast<double>(sliderLength - m_iHandleLength);
         if (!m_bHorizontal) {
-            m_value = 127. - m_value;
+            m_value = 1.0 - m_value;
         }
 
         // Emit valueChanged signal
@@ -128,9 +131,14 @@ void WSliderComposed::mouseMoveEvent(QMouseEvent * e) {
 }
 
 void WSliderComposed::wheelEvent(QWheelEvent *e) {
-    double wheelDirection = ((QWheelEvent *)e)->delta() / 120.;
-    double newValue = getValue() + (wheelDirection);
-    this->updateValue(newValue);
+    // For legacy (MIDI) reasons this is tuned to 127.
+    double wheelDirection = ((QWheelEvent *)e)->delta() / (120.0 * 127.0);
+    double newValue = getValue() + wheelDirection;
+
+    // Clamp to [0.0, 1.0]
+    newValue = math_max(0.0, math_min(1.0, newValue));
+
+    updateValue(newValue);
 
     e->accept();
 
@@ -192,18 +200,18 @@ void WSliderComposed::paintEvent(QPaintEvent *) {
     }
 }
 
-void WSliderComposed::setValue(double fValue) {
-    if (!m_bDrag && m_value != fValue) {
+void WSliderComposed::setValue(double dValue) {
+    if (!m_bDrag && m_value != dValue) {
         // Set value without emitting a valueChanged signal
         // and force display update
-        m_value = fValue;
+        m_value = dValue;
 
         // Calculate handle position
         if (!m_bHorizontal) {
-            fValue = 127-fValue;
+            dValue = 1.0 - dValue;
         }
         int sliderLength = m_bHorizontal ? width() : height();
-        m_iPos = (int)((fValue / 127.) * (double)(sliderLength - m_iHandleLength));
+        m_iPos = static_cast<int>(dValue * (sliderLength - m_iHandleLength));
 
         if (m_iPos > (sliderLength - m_iHandleLength)) {
             m_iPos = sliderLength - m_iHandleLength;
diff --git a/src/widget/wvumeter.cpp b/src/widget/wvumeter.cpp
index 363f114005..e099343619 100644
--- a/src/widget/wvumeter.cpp
+++ b/src/widget/wvumeter.cpp
@@ -103,9 +103,8 @@ void WVuMeter::setPixmaps(const QString &vuFilename,
     }
 }
 
-void WVuMeter::setValue(double fValue)
-{
-    int idx = (int)(fValue * (float)(m_iNoPos)/128.);
+void WVuMeter::setValue(double dValue) {
+    int idx = static_cast<int>(dValue * m_iNoPos);
     // Range check
     if (idx > m_iNoPos)
         idx = m_iNoPos;
@@ -113,7 +112,7 @@ void WVuMeter::setValue(double fValue)
         idx = 0;
 
     setPeak(idx);
-    m_value = fValue;
+    m_value = dValue;
 
     QTime currentTime = QTime::currentTime();
     int msecsElapsed = m_lastUpdate.msecsTo(currentTime);
@@ -160,7 +159,7 @@ void WVuMeter::paintEvent(QPaintEvent *) {
     }
 
     if (!m_pPixmapVu.isNull() && !m_pPixmapVu->isNull()) {
-        int idx = (int)(m_value*(float)(m_iNoPos)/128.);
+        int idx = static_cast<int>(m_value * m_iNoPos);
 
         // Range check
         if (idx > m_iNoPos)
diff --git a/src/widget/wwaveformviewer.cpp b/src/widget/wwaveformviewer.cpp
index 1c5b842215..cf10c0a511 100644
--- a/src/widget/wwaveformviewer.cpp
+++ b/src/widget/wwaveformviewer.cpp
@@ -100,11 +100,16 @@ void WWaveformViewer::mouseMoveEvent(QMouseEvent* event) {
         m_pScratchPosition->slotSet(targetPosition);
     } else if (m_bBending) {
         QPoint diff = event->pos() - m_mouseAnchor;
-        // start at the middle of 0-127, and emit values based on
-        // how far the mouse has traveled horizontally
-        double v = 64.0 + diff.x()/10.0f;
-        // clamp to [0, 127]
-        v = math_min(127.0, math_max(0.0, v));
+        // Start at the middle of [0.0, 1.0], and emit values based on how far
+        // the mouse has traveled horizontally. Note, for legacy (MIDI) reasons,
+        // this is tuned to 127.
+        // NOTE(rryan): This is basically a direct connection to the "wheel"
+        // control since we manually connect it in LegacySkinParser regardless
+        // of whether the skin specifies it. See ControlTTRotaryBehavior to see
+        // where this value is handled.
+        double v = 0.5 + (diff.x() / 1270.0);
+        // clamp to [0.0, 1.0]
+        v = math_min(1.0, math_max(0.0, v));
         emit(valueChangedRightDown(v));
     }
 }