blame: src/thumbnailworker.cpp

#include "thumbnailworker.h"

#include <QImageReader>

#include <QPainter>

ThumbnailWorker::ThumbnailWorker(const QString &path,

                                 int row,

                                 std::atomic_bool *cancelFlag)

    : m_path(path),

      m_row(row),

      m_cancelFlag(cancelFlag)

{

    setAutoDelete(true);

}

void ThumbnailWorker::run()

{

    if (*m_cancelFlag)

        return;

    QImageReader reader(m_path);

    reader.setAutoTransform(true);

    // Scale during decoding to avoid hitting the allocation limit

    // on very large images (Qt 6 defaults to 128 MB).

    QSize fullSize = reader.size();

    if (fullSize.isValid()) {

        QSize target = fullSize.scaled(128, 128, Qt::KeepAspectRatio);

        reader.setScaledSize(target);

    }

    QImage image = reader.read();

    if (*m_cancelFlag)

        return;

    if (!image.isNull())

    {

        // Scale to fit within 128x128 keeping aspect ratio

        // (may already be the right size if setScaledSize succeeded)

        QImage scaled = image.scaled(128, 128,

                                     Qt::KeepAspectRatio,

                                     Qt::SmoothTransformation);

        // Center on a 128x128 canvas with transparent/white fill

        QImage thumb(128, 128, QImage::Format_ARGB32_Premultiplied);

        thumb.fill(Qt::transparent);

        int x = (128 - scaled.width())  / 2;

        int y = (128 - scaled.height()) / 2;

        QPainter painter(&thumb);

        painter.drawImage(x, y, scaled);

        painter.end();

        emit finished(m_row, thumb);

    }

}