Method grabMagnifiedRegion

YACReader/viewer.cpp:925–1084

}

QImage Viewer::grabMagnifiedRegion(const QPoint &viewerPos, const QSize &glassSize, float zoomLevel) const
{
    const int glassW = glassSize.width();
    const int glassH = glassSize.height();
    const int zoomW = static_cast<int>(glassW * zoomLevel);
    const int zoomH = static_cast<int>(glassH * zoomLevel);
    const QColor bgColor = Configuration::getConfiguration().getBackgroundColor(theme.viewer.defaultBackgroundColor);

    if (continuousScroll) {
        // --- continuous mode ---
        // map viewer coords to continuousWidget coords
        const int scrollPos = verticalScrollBar()->sliderPosition();
        const int cwX = viewerPos.x();
        const int cwY = viewerPos.y() + scrollPos;
        const int widgetW = continuousWidget->width();

        // use the page under the cursor to derive source-to-widget scale factors,
        // so the result image is sized at source resolution (like single-page mode)
        int centerPageIdx = continuousViewModel->pageAtY(cwY);
        centerPageIdx = qBound(0, centerPageIdx, continuousViewModel->numPages() - 1);
        const QImage *centerImg = continuousPageProvider->image(centerPageIdx);
        const QSize centerScaledSize = continuousViewModel->scaledPageSize(centerPageIdx);

        float wFactor = 1.0f, hFactor = 1.0f;
        if (centerImg && !centerImg->isNull() && !centerScaledSize.isEmpty()) {
            wFactor = static_cast<float>(centerImg->width()) / centerScaledSize.width();
            hFactor = static_cast<float>(centerImg->height()) / centerScaledSize.height();
        }

        // result image sized in source-resolution pixels (full quality)
        const int resultW = static_cast<int>(zoomW * wFactor);
        const int resultH = static_cast<int>(zoomH * hFactor);

        QImage result(resultW, resultH, QImage::Format_RGB32);
        result.fill(bgColor);

        // zoom region in widget coordinates (centered on cursor)
        const int regionLeft = cwX - zoomW / 2;
        const int regionTop = cwY - zoomH / 2;
        const int regionRight = regionLeft + zoomW;
        const int regionBottom = regionTop + zoomH;

        // find which pages overlap the zoom region
        int firstPage = continuousViewModel->pageAtY(regionTop);
        int lastPage = continuousViewModel->pageAtY(regionBottom);
        firstPage = qBound(0, firstPage, continuousViewModel->numPages() - 1);
        lastPage = qBound(0, lastPage, continuousViewModel->numPages() - 1);

        QPainter painter(&result);
        for (int i = firstPage; i <= lastPage; ++i) {
            const QImage *srcImg = continuousPageProvider->image(i);
            if (!srcImg || srcImg->isNull()) {
                continue;
            }

            const QSize scaledSize = continuousViewModel->scaledPageSize(i);
            const int pageY = continuousViewModel->yPositionForPage(i);
            int pageX = (widgetW - scaledSize.width()) / 2;