Qt 彩色图片转换成黑白图

// 透明色为品红qRgba(255,0,255,255)

将非品红色转换成black,品红色转换成white,以做mask图用
QPixmap Form::convertToBW(const QImage &map)
{
 QImage img(map);
 for (int i = 0; i < img.height(); i++)
 {
  for (int j = 0; j < img.width(); j++)
  {
   if(img.pixel(j, i) == qRgba(255,0,255,255))
    img.setPixel(j, i, qRgba(255,255,255,255));//Or you can use qRgba(0,0,0,0) instead for trans
   else
    img.setPixel(j, i, qRgba(0,0,0,255));//Or you can use qRgba(0,0,0,0) instead for trans
  }
 }
 return QPixmap::fromImage(img, Qt::MonoOnly);
};

 

QPixmap Form::convertToBW(const QString &file)
{
 QImage img;
 img.load(file);
 return convertToBW(img);
}

调用方法：
QPixmap piximg = convertToBW("bg.png");
 piximg.save("kk05.png");