QImage转换图片格式，并替换特定颜色像素

Widget ::Widget ( QWidget *parent ) :

    QWidget(parent),

    ui(new Ui::Widget)

{

    ui->setupUi(this);

    QImage img("./111.jpg");

//    QImage img("./222.png");

    qDebug()<<img.format();

    union myrgb

    {

        uint rgba;

        uchar rgba_bits[4];

    };

    myrgb* mybits =(myrgb*) img.bits();

    int len = img.width()*img.height();

    while(len --> 0)

    {

        mybits->rgba = (mybits->rgba_bits[3]== 0)?0xffffffff:mybits->rgba;

        mybits++;

    }

    img.convertToFormat(QImage::Format_RGB888);

    img=img.scaled(260,260*img.height()/img.width());

    img.save("./img.bmp","bmp");

    ui->label->resize(260,260*img.height()/img.width());

    ui->label->setPixmap(QPixmap("./img.bmp").scaled(ui->label->size()));

}