// TODO: Set the fader position.
ui->faders->addWidget(channel);
- connect(ui_audio_miniview->fader, &QAbstractSlider::valueChanged,
+ connect(ui_audio_miniview->fader, &NonLinearFader::dbValueChanged,
bind(&MainWindow::mini_fader_changed, this, ui_audio_miniview, bus_index, _1));
}
}
QString::fromStdString(format_db(threshold_dbfs, DB_WITH_SIGN)));
}
-void MainWindow::mini_fader_changed(Ui::AudioMiniView *ui, int channel, int value)
+void MainWindow::mini_fader_changed(Ui::AudioMiniView *ui, int channel, double volume_db)
{
- float volume_db = value * 0.1f;
-
char buf[256];
- snprintf(buf, sizeof(buf), "%+.1f dB", volume_db);
- ui->fader_label->setText(buf);
+ if (isfinite(volume_db)) {
+ snprintf(buf, sizeof(buf), "%+.1f dB", volume_db);
+ ui->fader_label->setText(buf);
+ } else {
+ ui->fader_label->setText("-∞ dB");
+ }
global_mixer->get_audio_mixer()->set_fader_volume(channel, volume_db);
}
--- /dev/null
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <vector>
+#include <utility>
+
+#include <QResizeEvent>
+#include <QPainter>
+#include <QStyle>
+#include <QStyleOptionSlider>
+
+#include "nonlinear_fader.h"
+
+using namespace std;
+
+namespace {
+
+vector<pair<double, double>> fader_control_points = {
+ // The main area is from +6 to -12 dB (18 dB), and we use half the slider range for it.
+ { 6.0, 0.0 },
+ { -12.0, 0.5 },
+
+ // -12 to -21 is half the range (9 dB). Halve.
+ { -21.0, 0.625 },
+
+ // -21 to -30 (9 dB) gets the same range as the previous one.
+ { -30.0, 0.75 },
+
+ // -30 to -48 (18 dB) gets half of half.
+ { -48.0, 0.875 },
+
+ // -48 to -84 (36 dB) gets half of half of half.
+ { -84.0, 1.0 },
+};
+
+double slider_fraction_to_db(double db)
+{
+ if (db <= fader_control_points[0].second) {
+ return fader_control_points[0].first;
+ }
+ if (db >= fader_control_points.back().second) {
+ return fader_control_points.back().first;
+ }
+ for (unsigned i = 1; i < fader_control_points.size(); ++i) {
+ const double x0 = fader_control_points[i - 1].second;
+ const double x1 = fader_control_points[i].second;
+ const double y0 = fader_control_points[i - 1].first;
+ const double y1 = fader_control_points[i].first;
+ if (db >= x0 && db <= x1) {
+ const double t = (db - x0) / (x1 - x0);
+ return y0 + t * (y1 - y0);
+ }
+ }
+ assert(false);
+}
+
+double db_to_slider_fraction(double x)
+{
+ if (x >= fader_control_points[0].first) {
+ return fader_control_points[0].second;
+ }
+ if (x <= fader_control_points.back().first) {
+ return fader_control_points.back().second;
+ }
+ for (unsigned i = 1; i < fader_control_points.size(); ++i) {
+ const double x0 = fader_control_points[i].first;
+ const double x1 = fader_control_points[i - 1].first;
+ const double y0 = fader_control_points[i].second;
+ const double y1 = fader_control_points[i - 1].second;
+ if (x >= x0 && x <= x1) {
+ const double t = (x - x0) / (x1 - x0);
+ return y0 + t * (y1 - y0);
+ }
+ }
+ assert(false);
+}
+
+} // namespace
+
+NonLinearFader::NonLinearFader(QWidget *parent)
+ : QSlider(parent)
+{
+ update_slider_position();
+}
+
+void NonLinearFader::setDbValue(double db)
+{
+ db_value = db;
+ update_slider_position();
+ emit dbValueChanged(db);
+}
+
+void NonLinearFader::paintEvent(QPaintEvent *event)
+{
+ QStyleOptionSlider opt;
+ this->initStyleOption(&opt);
+ QRect gr = this->style()->subControlRect(QStyle::CC_Slider, &opt, QStyle::SC_SliderGroove, this);
+ QRect sr = this->style()->subControlRect(QStyle::CC_Slider, &opt, QStyle::SC_SliderHandle, this);
+
+ // FIXME: Where does the slider_length / 2 come from? I can't really find it
+ // in the Qt code, but it seems to match up with reality.
+ int slider_length = sr.height();
+ int slider_min = gr.top() + (slider_length / 2);
+ int slider_max = gr.bottom() + (slider_length / 2) - slider_length + 1;
+
+ QPainter p(this);
+
+ // Draw some ticks every 6 dB.
+ // FIXME: Find a way to make the slider wider, so that we have more space for tickmarks
+ // and some dB numbering.
+ int x_margin = 5;
+ p.setPen(Qt::darkGray);
+ for (int db = -84; db <= 6; db += 6) {
+ int y = slider_min + lrint(db_to_slider_fraction(db) * (slider_max - slider_min));
+ p.drawLine(QPoint(0, y), QPoint(gr.left() - x_margin, y));
+ p.drawLine(QPoint(gr.right() + x_margin, y), QPoint(width() - 1, y));
+ }
+
+ QSlider::paintEvent(event);
+}
+
+void NonLinearFader::resizeEvent(QResizeEvent *event)
+{
+ QSlider::resizeEvent(event);
+ inhibit_updates = true;
+ setRange(0, event->size().height() - 1);
+ inhibit_updates = false;
+ update_slider_position();
+}
+
+void NonLinearFader::sliderChange(SliderChange change)
+{
+ QSlider::sliderChange(change);
+ if (change == QAbstractSlider::SliderValueChange && !inhibit_updates) {
+ if (value() == 0) {
+ db_value = -HUGE_VAL;
+ } else {
+ double frac = 1.0 - value() / (height() - 1.0);
+ db_value = slider_fraction_to_db(frac);
+ }
+ emit dbValueChanged(db_value);
+ }
+}
+
+void NonLinearFader::update_slider_position()
+{
+ inhibit_updates = true;
+ setValue(lrint((1.0 - db_to_slider_fraction(db_value)) * (height() - 1.0)));
+ inhibit_updates = false;
+}
projects / nageru / commitdiff