DrawRect and change color of pixels in all directions

[mythili]

Hi,
I am going to change the color of pixels when its white by dragging the mouse from one point to another. I am drawing a rectangle over the startp point and endpoint i.e., drawRect and checking the each pixel color. In mouseMove I am able to draw the rect in all directions but I am not able to highlight the pixels in all directions. This is done only from TopLeft to BottomRight. I need this same in all directions. Please help me. Here is my code.

@QPoint hili_start_point,hili_end_point;
int hili_start_x,hili_start_y,hili_end_x,hili_end_y;
QRect hiliselectionRect;

void writingArea::paintEvent(QPaintEvent *event)
{
QPainter painter(this);
painter.setPen(QPen(QBrush(QColor(0,0,0,180)),1,Qt::DashLine));
painter.setBrush(QBrush(QColor(255,255,0,180)));
painter.drawRect(hiliselectionRect);
}

void writingArea::mousePressEvent(QMouseEvent *event)
{
hili_start_point = event->pos();
hili_start_x = hili_start_point.x();
hili_start_y = hili_start_point.y();
hiliselectionRect.setTopLeft(event->pos());
hiliselectionRect.setBottomRight(event->pos());
}

void writingArea::mouseMoveEvent(QMouseEvent *event)
{
hiliselectionRect.setBottomRight(event->pos());
update();
}

void writingArea::mouseReleaseEvent(QMouseEvent *event)
{
hili_end_point = event->pos();
hili_end_x = hili_end_point.x();
hili_end_y = hili_end_point.y();

    QRgb col;
    QRect draw_rect(hili_start_x,hili_start_y,hili_end_x - hili_start_x,hili_end_y-hili_start_y);

    QPixmap high_pixmap(draw_rect.size());
    QImage high_image = image.copy(draw_rect);
    QPainter high_painter(&image);
    int width = draw_rect.width();
    int height = draw_rect.height();
    for (int i = hili_start_x; i < width + hili_start_x; ++i)
    {
        for (int j = hili_start_y; j < height + hili_start_y; ++j)
        {
            col = image.pixel(i, j);
            QColor tempColor(col);
            if (tempColor == Qt::white)
            {
                image.setPixel(i, j, qRgb(255,255,0));
            }
        }
    }
    int rad = (myPenWidth / 2) + 2;
    update(draw_rect.normalized().adjusted(-rad, -rad, +rad, +rad));

}@

[raven-worx]

[quote author="mythili" date="1369372022"]In mouseMove I am able to draw the rect in all directions but I am not able to highlight the pixels in all directions.[/quote]
What exactly do you mean with "highlight the pixels in all directions"?