adjust slider scensitivity

sliderValueChanged.cpp

void WaveformComponent::sliderValueChanged (juce::Slider *slider)
{
    if(slider == &zoom_slider_) {
        double v = slider->getValue();
        int const size_min = 64;    //! 2^6
        int const size_max = 16384; //! 2^14
        
        //! スライダーの感度を調整する変数。
        //! 値を大きくするほど、center位置でのズーム率が下がる
        double const amount = JUCE_LIVE_CONSTANT(1024);
        
        double const min_x = log(size_min + amount);
        double const max_x = log(size_max + amount);
        
        double r = v / slider->getMaximum();
        
        double const current_x = r * (max_x - min_x) + min_x;
        
        int new_size = (int)std::round(exp(current_x)) - amount;
        
        if(new_size < size_min) {
            new_size = size_min;
        }
        if(new_size > size_max) {
            new_size = size_max;
        }
        
        SetViewSize(new_size);
    }
}