C++ QContent::open方法代码示例

QImage ExifContentPlugin::thumbnail( const QContent &content, const QSize &size, Qt::AspectRatioMode mode )
{
    QImage image;

    QIODevice *device = content.open();

    if (device) {
        QExifImageHeader exif;

        if (exif.loadFromJpeg(device)) {
            image = exif.thumbnail();

            if (!image.isNull() && size.isValid())
                image = image.scaled(size, mode, Qt::SmoothTransformation);
        }

        device->close();

        delete device;
    }

    return image;
}

/*!
    Loads a thumbnail representation of \a content.  The thumbnail will be scaled to \a size
    according to the given aspect ratio mode.
*/
QImage QContentStore::thumbnail(const QContent &content, const QSize &size, Qt::AspectRatioMode mode)
{
    QImage thumbnail;

    QString thumbPath = thumbnailPath(content.fileName());

    QFileInfo thumbInfo(thumbPath);

    if (thumbInfo.exists()) {
        if (thumbInfo.lastModified() > content.lastUpdated())
            thumbnail = readThumbnail(thumbPath, size, mode);
    } else {
        thumbnail = QContentFactory::thumbnail(content, size, mode);
    }

    if (thumbnail.isNull()) {
        if (QIODevice *device = content.open()) {
            QImageReader reader(device);

            if (reader.canRead()) {
                QSize scaledSize = reader.size();

                reader.setQuality(25);
                if (scaledSize.width() > 128 || scaledSize.height() > 128) {
                    scaledSize.scale(QSize(128, 128), Qt::KeepAspectRatio);

                    reader.setQuality( 49 ); // Otherwise Qt smooth scales
                    reader.setScaledSize(scaledSize);
                    reader.read(&thumbnail);

                    if (!thumbnail.isNull()) {
                        QImageWriter writer(thumbPath, QByteArray::fromRawData("PNG", 3));
                        writer.setQuality(25);
                        writer.write(thumbnail);

                        if (size.isValid())
                            thumbnail = thumbnail.scaled(size, mode);
                    }
                } else {
                    if (size.isValid()) {
                        scaledSize.scale(size, mode);
                        reader.setQuality( 49 ); // Otherwise Qt smooth scales
                        reader.setScaledSize(scaledSize);
                    }
                    reader.read(&thumbnail);
                }
            }

            delete device;
        }
    }

    if (thumbnail.isNull() && content.type().startsWith(m_audioPrefix)) {
        QDir dir = QFileInfo(content.fileName()).absoluteDir();

        foreach (const QString &fileName, m_folderThumbnails) {
            if (dir.exists(fileName)) {
                thumbnail = readThumbnail(dir.absoluteFilePath(fileName), size, mode);
                break;
            }
        }
    }

void CameraMainWindow::takePhotoNow()
{
    QImage img = camera->videocaptureview->image();
    if ( snapRequest != 0 ) {
        // Rescale the image and pop it into a QDSData object
        QImage scaledimg = img.scaled( snap_max,
                                       Qt::KeepAspectRatio,
                                       Qt::SmoothTransformation);
        QByteArray savedImageData;
        {
            QDataStream stream( &savedImageData, QIODevice::WriteOnly );
            stream << QPixmap::fromImage( scaledimg );
        }
        QDSData snappedImage( savedImageData, QMimeType( "image/x-qpixmap" ) );

        // Send response with the data
        snapRequest->respond( snappedImage );

        // Reset snap mode
        setSnapMode( false );
        delete snapRequest;
        snapRequest = 0;

        // Finished serving QDS request so close the application
        close();
        hideWaitScreen();
    } else {
        showWaitScreen();
        QContent f;
        QList<QString> c;

        f.setType("image/jpeg");
        f.setName(tr("Photo, %1","date")
                .arg(QTimeString::localYMDHMS(QDateTime::currentDateTime(),QTimeString::Short)));
        f.setMedia( settings->location->documentPath() );

        c.append(camcat);
        f.setCategories(c);

        QIODevice*  contentDevice = f.open(QIODevice::WriteOnly);

        if (contentDevice != 0)
        {
            QImage  temp = img.convertToFormat(QImage::Format_RGB32);

            temp.save(contentDevice, "JPEG", pquality);

            contentDevice->close();

            f.commit();

            pushThumb(f, img);

            hideWaitScreen();

        }
        else
        {
            QString errorText = f.errorString();
            if (errorText.isEmpty())
                errorText = tr("Unknown error");

            QMessageBox::warning(0,
                                 tr("Error saving photo"),
                                 tr("Could not save photo: %1").arg(errorText));
        }
    }

    preview();
}