transmission/qt/ColumnResizer.cc

/*
 * This file Copyright (C) 2015 Mnemosyne LLC
 *
 * It may be used under the GNU GPL versions 2 or 3
 * or any future license endorsed by Mnemosyne LLC.
 *
 */

#include <QEvent>
#include <QGridLayout>
#include <QTimer>

#include "ColumnResizer.h"

namespace
{

int itemColumnSpan(QGridLayout* layout, QLayoutItem const* item)
{
    for (int i = 0, count = layout->count(); i < count; ++i)
    {
        if (layout->itemAt(i) != item)
        {
            continue;
        }

        int row, column, rowSpan, columnSpan;
        layout->getItemPosition(i, &row, &column, &rowSpan, &columnSpan);
        return columnSpan;
    }

    return 0;
}

} // namespace

ColumnResizer::ColumnResizer(QObject* parent) :
    QObject(parent),
    myTimer(new QTimer(this)),
    myLayouts()
{
    myTimer->setSingleShot(true);
    connect(myTimer, SIGNAL(timeout()), SLOT(update()));
}

void ColumnResizer::addLayout(QGridLayout* layout)
{
    myLayouts << layout;
    scheduleUpdate();
}

bool ColumnResizer::eventFilter(QObject* object, QEvent* event)
{
    if (event->type() == QEvent::Resize)
    {
        scheduleUpdate();
    }

    return QObject::eventFilter(object, event);
}

void ColumnResizer::update()
{
    int maxWidth = 0;

    for (QGridLayout* const layout : myLayouts)
    {
        for (int i = 0, count = layout->rowCount(); i < count; ++i)
        {
            QLayoutItem* item = layout->itemAtPosition(i, 0);

            if (item == nullptr || itemColumnSpan(layout, item) > 1)
            {
                continue;
            }

            maxWidth = qMax(maxWidth, item->sizeHint().width());
        }
    }

    for (QGridLayout* const layout : myLayouts)
    {
        layout->setColumnMinimumWidth(0, maxWidth);
    }
}

void ColumnResizer::scheduleUpdate()
{
    myTimer->start(0);
}