aspectratiolayout.cpp

#include "aspectratiolayout.h"

AspectRatioLayout::AspectRatioLayout(QWidget *parent)
    : QLayout(parent), item(nullptr)
{}

AspectRatioLayout::~AspectRatioLayout()
{
    if (item)
        delete item;
}

void AspectRatioLayout::addItem(QLayoutItem *item)
{
    if(this->item)
        qWarning("AspectRatioLayout: Attempting to add more items.");
    this->item = item;
}

QLayoutItem *AspectRatioLayout::itemAt(int index) const
{
    if (index == 0)
        return item;
    return nullptr;
}

QLayoutItem *AspectRatioLayout::takeAt(int index)
{
    if (index == 0) {
        QLayoutItem *temp = item;
        item = nullptr;
        return temp;
    }
    return nullptr;
}

int AspectRatioLayout::count() const
{
    if (item)
        return 1;
    return 0;
}

QSize AspectRatioLayout::minimumSize() const
{
    if (item)
        return item->minimumSize();
    return QSize();
}

QSize AspectRatioLayout::sizeHint() const
{
    if (item)
        return item->sizeHint();
    return QSize();
}

void AspectRatioLayout::setGeometry(const QRect &rect)
{
    QLayout::setGeometry(rect);
     if (!item) return;

     auto height = rect.height();
     QSize hint = item->sizeHint();
     qreal aspectRatio = 0;
     if (hint.width() && hint.height())
             aspectRatio = static_cast<qreal>(hint.width()) / hint.height();

     auto currentWidth = qRound(rect.height() * aspectRatio);
     if (currentWidth <= rect.width()) {
         int offset = (rect.width() - currentWidth) / 2;
         item->setGeometry(QRect(rect.x() + offset, rect.y(), currentWidth, rect.height()));
     } else {
         int currentHeight = qRound(rect.width() / aspectRatio);
         int offset = (height - currentHeight) / 2;
         item->setGeometry(QRect(rect.x(), rect.y() + offset, rect.width(), currentHeight));
     }
}

Qt::Orientations AspectRatioLayout::expandingDirections() const
{
    return Qt::Orientations(0);
}