hashtags/lmms
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases 1 Wiki Activity

Support for dB models

Browse Source 
Add support for models that are in dB.

There's a new member `m_modelIsLinear` which can be set via the
constructor. The default value in the constructor is `true`.

Add the method `modelIsLinear` which can be used to query the parameter.
It is used in `calculateKnobPosYFromModel` and
`setVolumeByLocalPixelValue`. Both methods got extended to deal with
models in dB. They were also refactored to extract code that is common
for both cases.

Ensure that the constructor of `Fader` is called with `false` for
`CrossoverEQControlDialog` and `EqFader` because these use models that
are in dB.
This commit is contained in:
Michael Gregorius
2024-12-24 13:46:02 +01:00
parent f8e0bf5184
commit def44aee63
4 changed files with 91 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

131
src/gui/widgets/Fader.cpp
View File

@@ -62,9 +62,10 @@ namespace lmms::gui
SimpleTextFloat* Fader::s_textFloat = nullptr;
Fader::Fader(FloatModel* model, const QString& name, QWidget* parent) :
Fader::Fader(FloatModel* model, const QString& name, QWidget* parent, bool modelIsLinear) :
QWidget(parent),
FloatModelView(model, this)
FloatModelView(model, this),
m_modelIsLinear(modelIsLinear)
{
if (s_textFloat == nullptr)
{
@@ -85,8 +86,8 @@ Fader::Fader(FloatModel* model, const QString& name, QWidget* parent) :
}
Fader::Fader(FloatModel* model, const QString& name, QWidget* parent, const QPixmap& knob) :
Fader(model, name, parent)
Fader::Fader(FloatModel* model, const QString& name, QWidget* parent, const QPixmap& knob, bool modelIsLinear) :
Fader(model, name, parent, modelIsLinear)
{
m_knob = knob;
}
@@ -191,37 +192,55 @@ void Fader::wheelEvent (QWheelEvent* ev)
int Fader::calculateKnobPosYFromModel() const
{
// This method calculates the pixel position where the lower end of
// the fader knob should be for the amplification value in the model.
//
// The following assumes that the model describes an amplification,
// i.e. that values are in [0, max] and that 1 is unity, i.e. 0 dbFS.
auto* m = model();
auto const minV = model()->minValue();
auto const maxV = model()->maxValue();
auto const value = model()->value();
auto const minV = m->minValue();
auto const maxV = m->maxValue();
auto const value = m->value();
auto const distanceToMin = value - minV;
// Prevent dbFS calculations with zero or negative values
if (distanceToMin <= 0)
if (modelIsLinear())
{
return height();
// This method calculates the pixel position where the lower end of
// the fader knob should be for the amplification value in the model.
//
// The following assumes that the model describes an amplification,
// i.e. that values are in [0, max] and that 1 is unity, i.e. 0 dbFS.
auto const distanceToMin = value - minV;
// Prevent dbFS calculations with zero or negative values
if (distanceToMin <= 0)
{
return height();
}
else
{
auto const maxDb = ampToDbfs(maxV);
// Make sure that we do not get values less that the minimum fader dbFS
// for the calculations that will follow.
auto const actualDb = std::max(m_faderMinDb, ampToDbfs(value));
auto const ratio = (actualDb - m_faderMinDb) / (maxDb - m_faderMinDb);
// This returns results between:
// * m_knob.height() for a ratio of 1
// * height() for a ratio of 0
return height() - (height() - m_knob.height()) * std::pow(ratio, 3.);
}
}
else
{
auto const maxDb = ampToDbfs(maxV);
// The model is in dB so we just show that in a linear fashion
auto const clampedValue = std::clamp(value, minV, maxV);
// Make sure that we do not get values less that the minimum fader dbFS
// for the calculations that will follow.
auto const actualDb = std::max(m_faderMinDb, ampToDbfs(value));
auto const ratio = (actualDb - m_faderMinDb) / (maxDb - m_faderMinDb);
auto const ratio = (clampedValue - minV) / (maxV - minV);
// This returns results between:
// * m_knob.height() for a ratio of 1
// * height() for a ratio of 0
return height() - (height() - m_knob.height()) * std::pow(ratio, 3.);
return height() - (height() - m_knob.height()) * ratio;
}
}
@@ -234,37 +253,49 @@ void Fader::setVolumeByLocalPixelValue(int y)
// Assume that the middle of the fader should go there.
int const lowerFaderKnob = y + (m_knob.height() / 2);
if (lowerFaderKnob >= height())
// In some cases we need the clamped lower position of the fader knob so we can ensure
// that we only set allowed values in the model range.
int const clampedLowerFaderKnob = std::clamp(lowerFaderKnob, m_knob.height(), height());
if (modelIsLinear())
{
// We have to check this before clamping because otherwise we wouldn't be able to set -inf dB!
model()->setValue(0);
if (lowerFaderKnob >= height())
{
// Check the non-clamped value because otherwise we wouldn't be able to set -inf dB!
model()->setValue(0);
}
else
{
// We are in the case where we set a value that's different from -inf dB so we use the clamped value
// of the lower knob position so that we only set allowed values in the model range.
// First map the lower knob position to [0, 1] so that we can apply some curve mapping, e.g.
// square, cube, etc.
LinearMap<float> knobMap(float(m_knob.height()), 1., float(height()), 0.);
// Apply the inverse of what is done in calculateKnobPosYFromModel
auto const knobPos = std::pow(knobMap.map(clampedLowerFaderKnob), 1./3.);
float const maxDb = ampToDbfs(m->maxValue());
LinearMap<float> dbMap(1., maxDb, 0., m_faderMinDb);
float const dbValue = dbMap.map(knobPos);
// Pull everything that's quieter than the minimum fader dbFS value down to 0 amplification.
// This should not happen due to the steps above but let's be sure.
// Otherwise compute the amplification value from the mapped dbFS value but make sure that we
// do not exceed the maximum dbValue of the model
float ampValue = dbValue < m_faderMinDb ? 0. : dbfsToAmp(std::min(maxDb, dbValue));
model()->setValue(ampValue);
}
}
else
{
// We are in the case where we set a value different from -inf dB so we first clamp the
// lower position of the fader knob so that we only set allowed values in the model range.
int const clampedLowerFaderKnob = std::clamp(lowerFaderKnob, m_knob.height(), height());
LinearMap<float> valueMap(float(m_knob.height()), model()->maxValue(), float(height()), model()->minValue());
// First map the lower knob position to [0, 1] so that we can apply some curved mapping, e.g.
// square, cube, etc.
LinearMap<float> knobMap(float(m_knob.height()), 1., float(height()), 0.);
// Apply the inverse of what is done in calculateKnobPosYFromModel
auto const knobPos = std::pow(knobMap.map(clampedLowerFaderKnob), 1./3.);
float const maxDb = ampToDbfs(m->maxValue());
LinearMap<float> dbMap(1., maxDb, 0., m_faderMinDb);
float const dbValue = dbMap.map(knobPos);
// Pull everything that's quieter than the minimum fader dbFS value down to 0 amplification.
// This should not happen due to the steps above but let's be sure.
// Otherwise compute the amplification value from the mapped dbFS value but make sure that we
// do not exceed the maximum dbValue of the model
float ampValue = dbValue < m_faderMinDb ? 0. : dbfsToAmp(std::min(maxDb, dbValue));
model()->setValue(ampValue);
model()->setValue(valueMap.map(clampedLowerFaderKnob));
}
}