QImage::setPixel: Index ... out of range

void codec::on_MAP_clicked()
{  
    for(int y=1; y<height-1; y++)
    {
        for (int x=1; x<width-1; x++)
        {
            picture_copy.setPixel(x, y, call_MAP(x, y));
        }
    }
 }

QRgb codec::call_MAP(int w, int h)
{
    int r, g, b;
    QRgb pixel_val, pixel_val_1, pixel_val_2, pixel_val_3;
//======================P(x)
    pixel_val=picture.pixel(w,h);
    pixel_val_1=picture.pixel(w-1, h);
    pixel_val_2=picture.pixel(w,h-1);
    pixel_val_3=picture.pixel(w-1,h-1);

//=======================================================================R
    if (qMax(qRed(pixel_val_1), qRed(pixel_val_2))<=qRed(pixel_val_3))
    {
        r=qMin(qRed(pixel_val_1), qRed(pixel_val_2));
    }

    else if (qMin(qRed(pixel_val_1), qRed(pixel_val_2))>=qRed(pixel_val_3))
    {
        r=qMax(qRed(pixel_val_1), qRed(pixel_val_2));
    }

    else
    {
        r=qRed(pixel_val_1)+qRed(pixel_val_2)-qRed(pixel_val_3);
    }
//=======================================================================G
    if (qMax(qGreen(pixel_val_1), qGreen(pixel_val_2))<=qGreen(pixel_val_3))
    {
        g=qMin(qGreen(pixel_val_1), qGreen(pixel_val_2));
    }

    else if (qMin(qGreen(pixel_val_1), qGreen(pixel_val_2))>=qGreen(pixel_val_3))
    {
        g=qMax(qGreen(pixel_val_1), qGreen(pixel_val_2));
    }

    else
    {
        g=qGreen(pixel_val_1)+qGreen(pixel_val_2)-qGreen(pixel_val_3);
    }


//=======================================================================B

    if (qMax(qBlue(pixel_val_1), qBlue(pixel_val_2))<=qBlue(pixel_val_3))
    {
        b=qMin(qBlue(pixel_val_1), qBlue(pixel_val_2));
    }

    else if (qMin(qBlue(pixel_val_1), qBlue(pixel_val_2))>=qBlue(pixel_val_3))
    {
        b=qMax(qBlue(pixel_val_1), qBlue(pixel_val_2));
    }

    else
    {
        b=qBlue(pixel_val_1)+qBlue(pixel_val_2)-qBlue(pixel_val_3);
    }

     pixel_val=qRgb(r, g, b);
     return pixel_val;
}

pixel_val=qRgb(r, g, b); 

    if (picture_name.isNull())
    {
        ui->results->setText("Picture not inserted");
        return;
    }

void codec::on_MAP_clicked() {
    picture_copy = QImage(width, height, QImage::Format_RGB888);
    for(int y=1; y<height-1; y++) { // czy tu nie powinno być y=0?
        for (int x=1; x<width-1; x++) { // czy tu nie powinno być x=0?
            picture_copy.setPixel(x, y, call_MAP(x, y));
        }
    }
}