Qt 改变图片亮度算法

QImage Bright1(QImage &image,int brightness)
{
	uchar *line =image.scanLine(0); 
	uchar *pixel = line;

	for (int y = 0; y < image.height(); ++y)
	{
		pixel = line;
		for (int x = 0; x < image.width(); ++x)
		{
			*pixel = qBound(0, *pixel + brightness, 255);
			*(pixel + 1) = qBound(0, *(pixel + 1) + brightness, 255);
			*(pixel + 2) = qBound(0, *(pixel + 2) + brightness, 255);
			pixel += 4;
		}

		line += image.bytesPerLine();
	}
	return image;
}


QImage Bright2(QImage &image,int brightness)
{
	QImage origin = image;
	QColor oldColor;
	int delta = brightness;
	int r=0,g=0,b=0;
	uchar *line =image.scanLine(0); 
	uchar *pixel = line;
	QImage * newImage = new QImage(origin.width(), origin.height(), QImage::Format_ARGB32);
	for(int y=0; y<newImage->height(); ++y)
	{
		for(int x=0; x<newImage->width(); ++x)
		{
			oldColor = QColor(image.pixel(x,y));
			r = oldColor.red() + brightness;
			g = oldColor.green() + brightness;
			b = oldColor.blue() + brightness;
			newImage->setPixel(x,y, qRgb(r,g,b));
		}
	}

	return *newImage;
}
 
QImage Bright3(QImage& source, int factor)
{
	if (factor < -255 || factor > 255)
		return source;

	int red, green, blue;
	int pixels = source.width() * source.height();
	unsigned int *data = (unsigned int *)source.bits();
	for (int i = 0; i < pixels; ++i)
	{
		red= qRed(data[i])+ factor;
		red = (red < 0x00) ? 0x00 : (red > 0xff) ? 0xff : red;
		green= qGreen(data[i])+factor;
		green = (green < 0x00) ? 0x00 : (green > 0xff) ? 0xff : green;
		blue= qBlue(data[i])+factor;
		blue =  (blue  < 0x00) ? 0x00 : (blue  > 0xff) ? 0xff : blue ;
		data[i] = qRgba(red, green, blue, qAlpha(data[i]));
	}
	return source;
}