Method GetFrame

src/QtImageReader.cpp:151–192

Get an openshot::Frame object for a specific frame number of this reader.

// Get an openshot::Frame object for a specific frame number of this reader.
std::shared_ptr<Frame> QtImageReader::GetFrame(int64_t requested_frame)
{
    // Check for open reader (or throw exception)
    if (!is_open)
        throw ReaderClosed("The Image is closed.  Call Open() before calling this method.", path.toStdString());

	// Create a scoped lock, allowing only a single thread to run the following code at one time
	const std::lock_guard<std::recursive_mutex> lock(getFrameMutex);

    // Calculate max image size
    QSize current_max_size = calculate_max_size();

    // Scale image smaller (or use a previous scaled image)
    if (!cached_image || max_size != current_max_size) {
        // Check for SVG files and rasterize them to QImages
        if (path.toLower().endsWith(".svg") || path.toLower().endsWith(".svgz")) {
            load_svg_path(path);
        }

        // We need to resize the original image to a smaller image (for performance reasons)
        // Only do this once, to prevent tons of unneeded scaling operations
        cached_image = std::make_shared<QImage>(image->scaled(
                       current_max_size,
                       Qt::KeepAspectRatio, Qt::SmoothTransformation));

        // Set max size (to later determine if max_size is changed)
        max_size = current_max_size;
    }

    auto sample_count = Frame::GetSamplesPerFrame(
        requested_frame, info.fps, info.sample_rate, info.channels);
    auto sz = cached_image->size();

    // Create frame object
    auto image_frame = std::make_shared<Frame>(
            requested_frame, sz.width(), sz.height(), "#000000",
            sample_count, info.channels);
    image_frame->AddImage(cached_image);

    // return frame object
    return image_frame;
}

// Calculate the max_size QSize, based on parent timeline and parent clip settings
QSize QtImageReader::calculate_max_size() {