Files
lmms/plugins/CrossoverEQ/CrossoverEQControlDialog.cpp
Michael Gregorius 3c3441bb0c Faders with a dB scale (instead of linear/percentage) (#7636)
* Use dbFS scale for the faders

Make the faders use a linear dbFS scale. They now also change position on first click and can then be dragged.

The `Fader` class now has a new property called `m_faderMinDb`. It's the minimum value before the amplification drops down fully to 0. It is needed because we cannot represent a scale from -inf to maxDB.

Rename `knobPosY` to `calculateKnobPosYFromModel` and move the implementation into the cpp file. The method now first converts the model's current amplification value to dbFS and then computes a ratio based on that values and the minimum and maximum dbFS values.

Add the method `setVolumeByLocalPixelValue` which takes a local y coordinate of the widget and sets the amplification of the model based on a dbFS scale.

Adjust `mousePressEvent` and `mouseMoveEvent` so that they mostly take the local y coordinate of the event and use that to adjust the model via `setVolumeByLocalPixelValue`.

Remove `m_moveStartPoint` and `m_startValue` and they are not needed anymore.

* Apply curve to faders

Apply a curve, i.e. the cube function and its inverse, to the fader
positions to that we have more space to work with in the "interesting"
areas around 0 dB and less space in the area where we tend to "-inf dB".

Set the minimum dB value of the fader to -120 dB to increase the potential
headroom.

* Support for dB models

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.

* Show current dB value of fader in tool tip

Show the current value of the fader in its tool tip. Please note that
this value is always shown in dB because the goal should be to get rid
of the linear values for the faders.

Some of the code is extracted into the new method
`Fader::getModelValueAsDbString` which is shared by
`Fader::modelValueChanged` (also new) and `Fader::updateTextFloat`.

Please note that `getModelValueAsDbString` will use "dB" instead of
"dBFS" as the unit and that it will format "-inf dB" instead of "-∞ dB".
These changes will also be visible in the text float that is used to
show the new values as the fader is being dragged.

* Let users enter values in dB

Let users enter values in dB in the dialog that opens with a double
click.

The minimum value that can be entered is the minimum value that the
fader allows to set, i.e. -120 dB. The maximum value is the maximum
value of the model converted to dB. As of now this is ~6 dB. The
current value is converted to dB. If it corresponds to "-inf dB", i.e.
if the amplification is 0 then the minimum value is used.

* Remove option "Display volume as dBFS"

Remove the option "Display volume as dBFS" from the settings dialog and
the check box option "Volume as dBFS" from the "View" menu. Volumes are
now always treated as dB, i.e. all evaluations of the property
"displaydbfs" have been removed which results in assuming that this
option is always true.

The upgrade code in `ConfigManager::upgrade_1_1_91` was left as is.
However, a note was added which informs the reader that the value of
"displaydbfs" is not evaluated anymore.

* Extend Fader::wheelEvent

Extend `Fader::wheelEvent` for the case where the model is not a dB
model (`modelIsLinear() == true`), e.g. for the mixer faders. In that
case it works as follows. Each step increments or decrements by 1 dB if
no modifier is pressed. With "Shift" pressed the increment value is 3 dB.
With "STRG" ("CTRL") pressed the increment value is reduced to 0.1 dB. If
the value goes below the minimum positive dB value that is allowed by the
fader then the fader is set to "-inf dB", i.e. zero amplification. If the
fader is set to "-inf dB" and the users want to increase the value then
it is first set to the minimum positive value that is allowed by the
fader.

If the model is a dB model then the same behavior as before is used.
Although it should be considered to adjust this case as well. These
models are used by the faders of the Crossover Equalizer, Equalizer,
Compressor and Delay and they are not very usable with the mouse wheel.

* Adjust the wheel behavior for faders with dB models

Make the faders of the Crossover Equalizer, Equalizer, Compressor and
Delay behave like the mixer faders, i.e. step in sizes of 3 dB, 1dB and
0.1 dB depending on whether a modifier key is pressed or not.

Extract some common code to do so and add some `const` keywords.

* Less "jumpy" knobs

Implement a more stable knob behavior.

Remove the jumping behavior if the users directly click on a volume
knob. By storing the offset from the knob center and taking it into
account during the changes it now also feels like the users are
dragging the knob.

Changes to the amplification are now only applied when the mouse is
moved. This makes the double click behavior much more stable, i.e. if
users click on the knob when it is at 0 dB the dialog will also show
0 dB and not something like 0.3 dB because the first click is already
registered as a change of volume.

If the users click next to the knob the amplification will still be
changed immediately to that value.

## Technical details

To make the knobs more stable a variable called `m_knobCenterOffset` was
introduced. It stores the offset of the click from the knob center so
that this value can be taken into account for in the method
`setVolumeByLocalPixelValue`.

* Make MSVC happy

Add an indication that a float value is assigned to a float variable.

* Introduce constexpr for scaling exponent

Introduce the `constexpr c_dBScalingExponent` which describes the
scaling exponent that's used to scale the dB scale in both directions.
This will simplify potential adjustments by keeping the values
consistent everywhere.

* Draw fader ticks

Draw fader ticks in case the model is a linear one. This means that for
now they should only be painted for the mixer faders but not for the
faders of the Compressor, Delay, etc.

Extract the computation of the scaled ratio between the maximum model dB
value and the minimum supported fader dB value into the new private
method `computeScaledRatio`. This is necessary because it is needed to
paint the fader knob at the correct position (using the knob bottom as
the reference) and to paint the fader ticks at the correct position
(using the knob center).

Introduce the private method `paintFaderTicks` which paints the fader
ticks.

Note: to paint some non-evenly spaced fader ticks replace the `for`
expression in `paintFaderTicks` with something like the following:
```
for (auto & i : {6.f, 0.f, -6.f, -12.f, -24.f, -36.f, -48.f, -60.f, -72.f, -84.f, -96.f, -108.f, -120.f})
```

* Fader adjustments via keyboard

Allow the adjustment of the faders via the keyboard. Using the up or
plus key will increment the fader value whereas the down or minus key
will decrement it. The same key modifiers as for the wheel event apply:
* No modifier: adjust by 1 dB
* Shift: adjust by 3 dB
* Control: adjust by 0.1 dB

Due to the very similar behavior of the mouse wheel and key press
handling some common functionality was factored out:
* Determinination of the (absolute) adjustment delta value by
  insprecting the modifier keys of an event. Factored into
  `determineAdjustmentDelta`.
* Adjustment of the model by a given dB delta value. Factored into
  `adjustModelByDBDelta`.

* Move the fader of the selected channel

Move the fader of the selected channel instead of the fader that has
focus when the up/plus or down/minus keys are pressed. Doing so also
feels more natural because users can already change the selected
channel via the left and right keys and now they can immediately adjust
the volume of the currently selected channel while doing so.

Key events are now handled in `MixerView::keyPressEvent` instead of
`Fader::keyPressEvent` and the latter is removed. `MixerChannelView`
now has a method called `fader` which provides the associated fader.
This is needed so that the event handler of `MixerView` can act upon
the currently selected fader.

## Changes in Fader
The `Fader` class provides two new public methods.

The `adjust` method takes the modifier key(s) and the adjustment
direction and then decides internally how the modifier keys are mapped
to increment values. This is done to keep the mapping between modifier
keys and increment values consistent across different clients, e.g. the
key event of the `MixerView` and the wheel event of the `Fader` itself.
The direction is provided by the client because the means to determine
the direction can differ between clients and cases, e.g. a wheel event
determines the direction differently than a key event does.

The method `adjustByDecibelDelta` simply adjusts the fader by the given
delta amount. It currently is not really used in a public way but it
still makes sense to provide this functionality in case a parent class
or client wants to manipulate the faders by its very own logic.

Because the `Fader` class does not react itself to key press events
anymore the call to `setFocusPolicy` is removed again.

* Enter fader value when space key pressed

Let the users enter the fader value via dialog when the space key is
pressed.

Extract the dialog logic into the new method `adjustByDialog` and call
it from `MixerView::keyPressEvent`.

Make `Fader::mouseDoubleClickEvent` delegate to `adjustByDialog` and
also fix the behavior by accepting the event.

* More prominent fader ticks around 0 dB

Make the fader ticks around 0 dB more prominent but drawing them
slightly wider and with a more opaque color.

* Work around a Qt bug

Work around a Qt bug in conjunction with the scroll wheel and the Alt
key. Simply return 0 for the fader delta as soon as Alt is pressed.

* Fix wheel events without any modifier

Fix the handling of wheel events without any modifier key being pressed.

Commit ff435d551b accidentally tested against Alt using a logical OR
instead of an AND.

* Code review changes

First set of code review changes:
* Use Doxygen style documentation comments
* Remove comment about `displaydbfs` from upgrade routine
* White-space changes for touched lines.

* Make minimum dB value a constexpr

Make the minimum dB value a constexpr in the implementation file because
currently it's an implementation detail that should not be of any
interest to any other client.

So `m_faderMinDb` becomes `c_faderMinDb`.

* More flexible painting of fader ticks

Paint the fader ticks in a more systematic and flexible way. This also
removes some "magic numbers", e.g. by using `c_faderMinDb` instead of
`-120.f` as the lower limit.

The upper limit, i.e. the "starting point" is now also computed using
the maximum value of the model so that the fader will still paint
correctly if it ever changes.

* Make the zero indicator bolder

Make the zero indicator tick of the fader bolder.

* Make rendering of fader ticks a preference

Make rendering of fader ticks a preference which is off by default.

Introduce the new option "Show fader ticks" to the setup dialog and save
it to the UI attribute `showfaderticks`.

The configuration value is currently evaluated in `Fader::paintEvent`.
If this leads to performance problems it might be better to introduce a
boolean member to the `Fader` class which caches that value.

* Move constexprs to anonymous namespace
2025-03-01 20:08:04 +01:00

120 lines
4.0 KiB
C++

/*
* CrossoverEQControlDialog.cpp - A native 4-band Crossover Equalizer
* good for simulating tonestacks or simple peakless (flat-band) equalization
*
* Copyright (c) 2014 Vesa Kivimäki <contact/dot/diizy/at/nbl/dot/fi>
* Copyright (c) 2006-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
*
* This file is part of LMMS - https://lmms.io
*
* This program 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 2 of the License, or (at your option) any later version.
*
* This program 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 this program (see COPYING); if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
*
*/
#include "CrossoverEQControlDialog.h"
#include "CrossoverEQControls.h"
#include "embed.h"
#include "LedCheckBox.h"
#include "Knob.h"
#include "Fader.h"
#include <QPixmap>
namespace lmms::gui
{
CrossoverEQControlDialog::CrossoverEQControlDialog( CrossoverEQControls * controls ) :
EffectControlDialog( controls )
{
setAutoFillBackground( true );
QPalette pal;
pal.setBrush( backgroundRole(), PLUGIN_NAME::getIconPixmap( "artwork" ) );
setPalette( pal );
setFixedSize( 167, 178 );
// knobs
auto xover12 = new Knob(KnobType::Bright26, this);
xover12->move( 29, 11 );
xover12->setModel( & controls->m_xover12 );
xover12->setLabel( "1/2" );
xover12->setHintText( tr( "Band 1/2 crossover:" ), " Hz" );
auto xover23 = new Knob(KnobType::Bright26, this);
xover23->move( 69, 11 );
xover23->setModel( & controls->m_xover23 );
xover23->setLabel( "2/3" );
xover23->setHintText( tr( "Band 2/3 crossover:" ), " Hz" );
auto xover34 = new Knob(KnobType::Bright26, this);
xover34->move( 109, 11 );
xover34->setModel( & controls->m_xover34 );
xover34->setLabel( "3/4" );
xover34->setHintText( tr( "Band 3/4 crossover:" ), " Hz" );
QPixmap const fader_knob(PLUGIN_NAME::getIconPixmap("fader_knob2"));
// faders
auto gain1 = new Fader(&controls->m_gain1, tr("Band 1 gain"), this, fader_knob, false);
gain1->move( 7, 56 );
gain1->setDisplayConversion( false );
gain1->setHintText( tr( "Band 1 gain:" ), " dBFS" );
gain1->setRenderUnityLine(false);
auto gain2 = new Fader(&controls->m_gain2, tr("Band 2 gain"), this, fader_knob, false);
gain2->move( 47, 56 );
gain2->setDisplayConversion( false );
gain2->setHintText( tr( "Band 2 gain:" ), " dBFS" );
gain2->setRenderUnityLine(false);
auto gain3 = new Fader(&controls->m_gain3, tr("Band 3 gain"), this, fader_knob, false);
gain3->move( 87, 56 );
gain3->setDisplayConversion( false );
gain3->setHintText( tr( "Band 3 gain:" ), " dBFS" );
gain3->setRenderUnityLine(false);
auto gain4 = new Fader(&controls->m_gain4, tr("Band 4 gain"), this, fader_knob, false);
gain4->move( 127, 56 );
gain4->setDisplayConversion( false );
gain4->setHintText( tr( "Band 4 gain:" ), " dBFS" );
gain4->setRenderUnityLine(false);
// leds
auto mute1 = new LedCheckBox("", this, tr("Band 1 mute"), LedCheckBox::LedColor::Green);
mute1->move( 15, 154 );
mute1->setModel( & controls->m_mute1 );
mute1->setToolTip(tr("Mute band 1"));
auto mute2 = new LedCheckBox("", this, tr("Band 2 mute"), LedCheckBox::LedColor::Green);
mute2->move( 55, 154 );
mute2->setModel( & controls->m_mute2 );
mute2->setToolTip(tr("Mute band 2"));
auto mute3 = new LedCheckBox("", this, tr("Band 3 mute"), LedCheckBox::LedColor::Green);
mute3->move( 95, 154 );
mute3->setModel( & controls->m_mute3 );
mute3->setToolTip(tr("Mute band 3"));
auto mute4 = new LedCheckBox("", this, tr("Band 4 mute"), LedCheckBox::LedColor::Green);
mute4->move( 135, 154 );
mute4->setModel( & controls->m_mute4 );
mute4->setToolTip(tr("Mute band 4"));
}
} // namespace lmms::gui