ImageProvider.cpp

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// ======================================================================
//  ImageProvider.cpp
// ======================================================================
//                   This file is a part of the book 
//             "Qt 5.10 Professional programming with C++"
//                       http://qt-book.com
// ======================================================================
//  Copyright (c) 2017 by Max Schlee
// ======================================================================

#include "ImageProvider.h"

// ----------------------------------------------------------------------
ImageProvider::ImageProvider()
    : QQuickImageProvider(QQuickImageProvider::Image)
{
}

// ----------------------------------------------------------------------
QImage ImageProvider::brightness(const QImage& imgOrig, int n)
{
    QImage imgTemp = imgOrig.convertToFormat(QImage::Format_ARGB32);
    qint32 nHeight = imgTemp.height();
    qint32 nWidth  = imgTemp.width();

    for (qint32 y = 0; y < nHeight; ++y) {
        QRgb* tempLine = reinterpret_cast<QRgb*>(imgTemp.scanLine(y));

        for (qint32 x = 0; x < nWidth; ++x) {
             int r = qRed(*tempLine) + n;
             int g = qGreen(*tempLine) + n;
             int b = qBlue(*tempLine) + n;
             int a = qAlpha(*tempLine);

             *tempLine++ = qRgba(r > 255 ? 255 : r < 0 ? 0 : r,
                                 g > 255 ? 255 : g < 0 ? 0 : g,
                                 b > 255 ? 255 : b < 0 ? 0 : b,
                                 a
                                );
        }
    }

    return imgTemp;
}

// ----------------------------------------------------------------------
QImage ImageProvider::requestImage(const QString& strId, QSize* ps, const QSize& /*requestedSize*/)
{
    QStringList lst = strId.split(";");
    bool        bOk = false;
    int         nBrightness = lst.last().toInt(&bOk);
    QImage      img = brightness(QImage(":/" + lst.first()), nBrightness);

    if (ps) {
        *ps = img.size();
    }

    return img;
}