#ifndef ASPECTRATIOWIDGET_HPP
#define ASPECTRATIOWIDGET_HPP

#include <QWidget>
#include <QBoxLayout>

class AspectRatioWidget : public QWidget
{
    Q_OBJECT
public:
    AspectRatioWidget(QWidget *parent = 0) : QWidget(parent)
    {
        m_layout = new QHBoxLayout();
        m_layout->setSpacing(0);
        m_layout->setContentsMargins(0, 0, 0, 0);
        setLayout(m_layout);
    }

    // the widget we want to keep the ratio
    void setAspectWidget(QWidget* widget, const double ratio = 1.0) {
        m_aspect_widget = widget;
        m_layout->addWidget(widget);
        m_ratio = ratio;
    }
    void setRatio(const double ratio) {
        m_ratio = ratio;
        applyAspectRatio();
    }

protected:
    void resizeEvent(QResizeEvent *event) {
        (void)event;
        applyAspectRatio();
    }

public slots:
    void applyAspectRatio() {
        int w = this->width();
        int h = this->height();
        double aspect = static_cast<double>(h)/static_cast<double>(w);

        if(aspect < m_ratio) // parent is too wide
        {
            int target_width = static_cast<int>(static_cast<double>(h)/m_ratio);
            m_aspect_widget->setMaximumWidth(target_width);
            m_aspect_widget->setMaximumHeight(h);

        }
        else // parent is too high
        {
            int target_heigth = static_cast<int>(static_cast<double>(w)*m_ratio);
            m_aspect_widget->setMaximumHeight(target_heigth);
            m_aspect_widget->setMaximumWidth(w);
        }
    }

private:
    QHBoxLayout* m_layout;

    QWidget* m_aspect_widget;

    double m_ratio;
};

#endif // ASPECTRATIOWINDOW_H