• Ell's avatar
    app: use adaptive chunk size when rendering projections · a1706bbd
    Ell authored
    In GimpProjection, use an adaptive chunk size when rendering the
    projection asynchronously, rather than using a fixed chunk size.
    The chunk size is determined according to the number of pixels
    processed during the last frame, and the time it took to process
    them, aiming for some target frame-rate (currently, 15 FPS).  In
    other words, the chunks become bigger when processing is fast, and
    smaller when processing is slow.  We're currently aiming for
    generally-square chunks, whose sides are powers of 2, within a
    predefined range.
    Note that the chunk size represents a trade off between throughput
    and responsiveness: bigger chunks result in better throughput,
    since each individual chunk incurs an overhead, in particular when
    rendering area filters or multithreaded ops, while smaller chunks
    result in better responsiveness, since the time each chunk
    individual takes to render is smaller, allowing us to more
    accurately meet the target frame rate.  With this commit, we aim to
    find a good compromise dynamically, rather than statically.
    The use of adaptive chunk sizes can be disabled by defining the
    environment variable GIMP_NO_ADAPTIVE_CHUNK_SIZE, in which case we
    use a fixed chunk size, as before.
gimpprojection.c 46.3 KB