Function main

compute/example/qimage_blur.cpp:92–145

this example shows how to load an image using Qt, apply a simple box blur filter, and then display it in a Qt window.

// this example shows how to load an image using Qt, apply a simple
// box blur filter, and then display it in a Qt window.
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    // check command line
    if(argc < 2){
        std::cout << "usage: qimage_blur [FILENAME]" << std::endl;
        return -1;
    }

    // load image using Qt
    QString fileName = argv[1];
    QImage qimage(fileName);

    size_t height = qimage.height();
    size_t width = qimage.width();
    size_t bytes_per_line = qimage.bytesPerLine();

    qDebug() << "height:" << height
             << "width:" << width
             << "bytes per line:" << bytes_per_line
             << "depth:" << qimage.depth()
             << "format:" << qimage.format();

    // create compute context
    compute::device gpu = compute::system::default_device();
    compute::context context(gpu);
    compute::command_queue queue(context, gpu);
    std::cout << "device: " << gpu.name() << std::endl;

    // get the opencl image format for the qimage
    compute::image_format format =
        compute::qt_qimage_format_to_image_format(qimage.format());

    // create input and output images on the gpu
    compute::image2d input_image(context, width, height, format);
    compute::image2d output_image(context, width, height, format);

    // copy host qimage to gpu image
    compute::qt_copy_qimage_to_image2d(qimage, input_image, queue);

    // apply box filter
    box_filter_image(input_image, output_image, 7, 7, queue);

    // copy gpu blurred image from to host qimage
    compute::qt_copy_image2d_to_qimage(output_image, qimage, queue);

    // show image as a pixmap
    QLabel label;
    label.setPixmap(QPixmap::fromImage(qimage));
    label.show();

    return app.exec();
}