MyDoubleSlider.cpp

// Copyright (c) 2014-2021 Josh Blum
// SPDX-License-Identifier: BSL-1.0

#include "MyDoubleSlider.hpp"
#include <cmath> //lround

MyDoubleSlider::MyDoubleSlider(const Qt::Orientation orientation, QWidget *parent):
    QSlider(orientation, parent),
    _minimum(0.0),
    _maximum(100.0),
    _stepSize(1.0)
{
    connect(this, &QSlider::valueChanged, this, &MyDoubleSlider::handleIntValueChanged);
}

double MyDoubleSlider::value(void) const
{
    int int_norm = QSlider::value()-QSlider::minimum();
    double scale = int_norm/double(QSlider::maximum()-QSlider::minimum());
    double float_norm = scale*(_maximum - _minimum);
    return float_norm + _minimum;
}

void MyDoubleSlider::setValue(const double val)
{
    double float_norm = val - _minimum;
    double scale = float_norm/(_maximum - _minimum);
    int int_norm = std::lround(scale*(QSlider::maximum()-QSlider::minimum()));
    QSlider::setValue(int_norm + QSlider::minimum());
}

void MyDoubleSlider::setMinimum(const double min)
{
    auto oldValue = this->value();
    _minimum = min;
    this->updateRange(oldValue);
}

void MyDoubleSlider::setMaximum(const double max)
{
    auto oldValue = this->value();
    _maximum = max;
    this->updateRange(oldValue);
}

void MyDoubleSlider::setSingleStep(const double val)
{
    auto oldValue = this->value();
    _stepSize = val;
    this->updateRange(oldValue);
}

void MyDoubleSlider::handleIntValueChanged(const int)
{
    emit this->valueChanged(this->value());
}

void MyDoubleSlider::updateRange(const double oldValue)
{
    QSlider::setMinimum(_minimum/_stepSize);
    QSlider::setMaximum(_maximum/_stepSize);
    this->setValue(oldValue);
}