From a621e80eb68901fa35ebaa02a86d5726b2bc16e3 Mon Sep 17 00:00:00 2001
From: Ivailo Monev <xakepa10@gmail.com>
Date: Fri, 24 May 2024 12:21:14 +0300
Subject: [PATCH] plasma: use 0 to 100 range for the mixer applet sliders

loses some precision but otherwise it is as if wheel events do nothing to
sliders if the ALSA volume range is big because wheel events are on fixed
delta instead of factor of the slider min and max (those of Plasma::Slider
anyway)

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>
---
 plasma/applets/mixer/mixer.cpp | 54 ++++++++++++++++++++++------------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/plasma/applets/mixer/mixer.cpp b/plasma/applets/mixer/mixer.cpp
index c3953591..26791d29 100644
--- a/plasma/applets/mixer/mixer.cpp
+++ b/plasma/applets/mixer/mixer.cpp
@@ -171,12 +171,6 @@ static int kVolumeStep()
     return qMax(QApplication::wheelScrollLines(), 1);
 }
 
-static int kStepVolume(const int value, const int maxvalue, const int step)
-{
-    const qreal valuefactor = (qreal(maxvalue) / 100);
-    return (value + (valuefactor * step));
-}
-
 static QIcon kMixerIcon(QObject *parent, const int value)
 {
     QIcon result;
@@ -228,6 +222,13 @@ public:
                          const QString &alsaelementname,
                          QGraphicsWidget *parent);
 
+
+    void setVolume(const long alsavolumemin, const long alsavolumemax, const long alsavolume);
+    long alsaVolume() const;
+
+    long alsavolumemin;
+    long alsavolumemax;
+    long alsavolume;
     uint alsaelementindex;
     snd_mixer_selem_channel_id_t alsaelementchannel;
     QString alsaelementname;
@@ -238,10 +239,33 @@ MixerSlider::MixerSlider(const uint _alsaelementindex,
                          const QString &_alsaelementname,
                          QGraphicsWidget *parent)
     : Plasma::Slider(parent),
+    alsavolumemin(0),
+    alsavolumemax(0),
+    alsavolume(0),
     alsaelementindex(_alsaelementindex),
     alsaelementchannel(_alsaelementchannel),
     alsaelementname(_alsaelementname)
 {
+    setOrientation(Qt::Vertical);
+    setRange(0, 100);
+    setValue(0);
+    setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Expanding);
+    setMinimumSize(s_minimumslidersize);
+    setToolTip(QString::fromLocal8Bit(snd_mixer_selem_channel_name(alsaelementchannel)));
+}
+
+void MixerSlider::setVolume(const long _alsavolumemin, const long _alsavolumemax, const long _alsavolume)
+{
+    alsavolumemin = _alsavolumemin;
+    alsavolumemax = _alsavolumemax;
+    alsavolume = _alsavolume;
+    setValue(kFixedVolume(alsavolume, alsavolumemax));
+}
+
+long MixerSlider::alsaVolume() const
+{
+    const qreal valuefactor = (qreal(alsavolumemax) / 100);
+    return (valuefactor * value());
 }
 
 
@@ -477,12 +501,7 @@ bool MixerTabWidget::setup(const QByteArray &alsacardname)
             }
             const QString alsaelementchannelname = QString::fromLocal8Bit(snd_mixer_selem_channel_name(alsaelementchannel));
             MixerSlider* slider = new MixerSlider(alsaelementindex, alsaelementchannel, alsaelementname, frame);
-            slider->setOrientation(Qt::Vertical);
-            slider->setRange(int(alsavolumemin), int(alsavolumemax));
-            slider->setValue(int(alsavolume));
-            slider->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Expanding);
-            slider->setMinimumSize(s_minimumslidersize);
-            slider->setToolTip(alsaelementchannelname);
+            slider->setVolume(alsavolumemin, alsavolumemax, alsavolume);
             connect(
                 slider, SIGNAL(sliderMoved(int)),
                 this, SLOT(slotSliderMovedOrChanged(int))
@@ -714,7 +733,7 @@ void MixerTabWidget::decreaseVolume()
 {
     foreach (MixerSlider *slider, sliders) {
         if (slider->alsaelementname == m_mainelement) {
-            slider->setValue(kStepVolume(slider->value(), slider->maximum(), -kVolumeStep()));
+            slider->setValue(qMax(slider->value() - kVolumeStep(), 0));
         }
     }
 }
@@ -722,7 +741,7 @@ void MixerTabWidget::increaseVolume()
 {
     foreach (MixerSlider *slider, sliders) {
         if (slider->alsaelementname == m_mainelement) {
-            slider->setValue(kStepVolume(slider->value(), slider->maximum(), kVolumeStep()));
+            slider->setValue(qMax(slider->value() + kVolumeStep(), 100));
         }
     }
 }
@@ -743,13 +762,13 @@ void MixerTabWidget::slotSliderMovedOrChanged(const int value)
             kDebug() << "Changing" << slider->alsaelementindex << "volume to" << value;
             const bool alsahascapture = snd_mixer_selem_has_capture_volume(alsaelement);
             if (alsahascapture) {
-                const int alsaresult = snd_mixer_selem_set_capture_volume(alsaelement, slider->alsaelementchannel, long(value));
+                const int alsaresult = snd_mixer_selem_set_capture_volume(alsaelement, slider->alsaelementchannel, slider->alsaVolume());
                 if (alsaresult != 0) {
                     kWarning() << "Could not set capture volume" << snd_strerror(alsaresult);
                     return;
                 }
             } else {
-                const int alsaresult = snd_mixer_selem_set_playback_volume(alsaelement, slider->alsaelementchannel, long(value));
+                const int alsaresult = snd_mixer_selem_set_playback_volume(alsaelement, slider->alsaelementchannel, slider->alsaVolume());
                 if (alsaresult != 0) {
                     kWarning() << "Could not set playback volume" << snd_strerror(alsaresult);
                     return;
@@ -834,8 +853,7 @@ int k_alsa_element_callback(snd_mixer_elem_t *alsaelement, unsigned int alsamask
                 if (!gotvolumes) {
                     continue;
                 }
-                slider->setRange(int(alsavolumemin), int(alsavolumemax));
-                slider->setValue(int(alsavolume));
+                slider->setVolume(alsavolumemin, alsavolumemax, alsavolume);
             }
         }
     }