Qt/C++ 改变图片亮度算法 注意是算法

由于项目需要，结合网上的资源，提供这三种方法来改变图片亮度

 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; yheight(); ++y)
     {
         for(int x=0; xwidth(); ++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;
 }

总体思路就是获取每一个像素点，再通过一个什么什么算法计算出该出该像素的值,再重新设置该像素点的值，差不多就是这样

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更多文章：http://blog.csdn.net/what951006