+#include "nonlinear_fader.h"
+
#include <assert.h>
#include <math.h>
-#include <stdio.h>
-#include <vector>
-#include <utility>
-
-#include <QResizeEvent>
#include <QPainter>
+#include <QPoint>
+#include <QRect>
#include <QStyle>
-#include <QStyleOptionSlider>
+#include <QStyleOption>
+#include <memory>
+#include <utility>
+#include <vector>
-#include "nonlinear_fader.h"
+#include "piecewise_interpolator.h"
+
+class QPaintEvent;
+class QWidget;
using namespace std;
namespace {
-vector<pair<double, double>> fader_control_points = {
+PiecewiseInterpolator interpolator({
// 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 },
+ // Adjust slightly so that the MIDI controller value of 106 becomes exactly 0.0 dB
+ // (cf. map_controller_to_float()); otherwise, we'd miss ever so slightly, which is
+ // really frustrating.
+ { 6.0, 1.0 },
+ { -12.0, 1.0 - (1.0 - 106.5/127.0) * 3.0 }, // About 0.492.
// -12 to -21 is half the range (9 dB). Halve.
- { -21.0, 0.625 },
+ { -21.0, 0.325 },
// -21 to -30 (9 dB) gets the same range as the previous one.
- { -30.0, 0.75 },
+ { -30.0, 0.25 },
// -30 to -48 (18 dB) gets half of half.
- { -48.0, 0.875 },
+ { -48.0, 0.125 },
// -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);
-}
+ { -84.0, 0.0 },
+});
} // namespace
// 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;
+ int slider_max = gr.top() + (slider_length / 2);
+ int slider_min = gr.bottom() + (slider_length / 2) - slider_length + 1;
QPainter p(this);
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));
+ int y = slider_min + lrint(interpolator.db_to_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 (value() == 0) {
db_value = -HUGE_VAL;
} else {
- double frac = 1.0 - value() / (height() - 1.0);
- db_value = slider_fraction_to_db(frac);
+ double frac = double(value() - minimum()) / (maximum() - minimum());
+ db_value = interpolator.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)));
+ double val = interpolator.db_to_fraction(db_value) * (maximum() - minimum()) + minimum();
+ setValue(lrint(val));
inhibit_updates = false;
}