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#include "pathwidget.h"
#include <QtGui/qpainter.h>

PathWidget::PathWidget(QWidget *parent)
    : QWidget(parent)
{
    setAttribute(Qt::WA_OpaquePaintEvent);

    if (!context.create())
        qFatal("Could not create OpenCL context");

    program = context.buildProgramFromSourceFile(QLatin1String(":/pathdrawing.cl"));

    fillRectWithColor = program.createKernel("fillRectWithColor");
    fillRectWithColor.setLocalWorkSize(8, 8);
}

PathWidget::~PathWidget()
{
}

void PathWidget::paintEvent(QPaintEvent *)
{
    // Create a QCLImage2D object for the window surface.
    QSize wsize = size();
    if (wsize != windowSize)
        surfaceImage = QCLImage2D();
    if (surfaceImage.isNull()) {
        windowSize = wsize;
        surfaceImage = context.createImage2DDevice
            (QImage::Format_RGB32, windowSize, QCLMemoryObject::ReadWrite);
    }

    // Clear to the background color.
    QColor bgcolor = palette().color(backgroundRole());
    fillRect(0, 0, wsize.width(), wsize.height(), bgcolor);

    // Draw a rectangle at 150, 100.
    fillRect(150, 100, 300, 200, Qt::black);

    // Draw the window surface image to the actual window.
    QPainter painter(this);
    surfaceImage.drawImage(&painter, QPoint(0, 0));
}

void PathWidget::fillRect(int x, int y, int width, int height,
                          const QColor& color)
{
    // Round up the global work size so we can process the
    // rectangle in 8x8 local work size units.  The kernel will
    // ignore pixels that are outside the rectangle limits.
    fillRectWithColor.setGlobalWorkSize((width + 7) & ~7, (height + 7) & ~7);
    fillRectWithColor(surfaceImage, x, y, x + width, y + height, color);
}