imageconverter.cpp

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/*
   Copyright (C) 2009 Canonical
   Author: Aurélien Gâteau <aurelien.gateau@canonical.com>

   This program is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation, either version 2 or 3 of the License.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
   General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "imageconverter.h"

#include <QDBusArgument>
#include <QDBusMetaType>
#include <QImage>

namespace ImageConverter
{

struct SpecImage
{
    int width, height, rowStride;
    bool hasAlpha;
    int bitsPerSample, channels;
    QByteArray data;
};

QDBusArgument &operator<<(QDBusArgument &argument, const SpecImage &image)
{
    argument.beginStructure();
    argument << image.width << image.height << image.rowStride << image.hasAlpha;
    argument << image.bitsPerSample << image.channels << image.data;
    argument.endStructure();
    return argument;
}

const QDBusArgument &operator>>(const QDBusArgument &argument, SpecImage &image)
{
    argument.beginStructure();
    argument >> image.width >> image.height >> image.rowStride >> image.hasAlpha;
    argument >> image.bitsPerSample >> image.channels >> image.data;
    argument.endStructure();
    return argument;
}

} // namespace

// This must be before the QVariant::fromValue below (#211726)
Q_DECLARE_METATYPE(ImageConverter::SpecImage)

namespace ImageConverter
{
QVariant variantForImage(const QImage &_image)
{
    qDBusRegisterMetaType<SpecImage>();

    QImage image = _image.convertToFormat(QImage::Format_ARGB32);

    int rowStride = image.width() * 4;

    // Notification spec stores pixels in R,G,B,A order, regardless of
    // endianess
    // Qt represents pixels as 32 bit unsigned int. So the order depend on
    // endianess:
    // - In big endian the order is A,R,G,B
    // - In little endian the order is B,G,R,A
    QByteArray data;
    data.resize(rowStride * image.height());
    char* dst = data.data();
    for (int y=0; y<image.height(); ++y) {
        QRgb* src = (QRgb*)image.scanLine(y);
        QRgb* end = src + image.width();
        for (;src != end; ++src) {
            // Probably slow, but free of endianess issues
            *dst++ = qRed(*src);
            *dst++ = qGreen(*src);
            *dst++ = qBlue(*src);
            *dst++ = qAlpha(*src);
        }
    }

    SpecImage specImage;
    specImage.width = image.width();
    specImage.height = image.height();
    specImage.rowStride = rowStride;
    specImage.hasAlpha = true;
    specImage.bitsPerSample = 8;
    specImage.channels = 4;
    specImage.data = data;

    return QVariant::fromValue(specImage);
}

} // namespace