QString file =QFileDialog::getSaveFileName(0,tr("choose a filename to save under"), QDir::currentPath(),"Images(*.bmp)");
if (image.isNull()){
QMessageBox::information(0, tr("Image SaveAs"),
tr("Cannot save to %1").arg(file));
ShowMessage("Null Image.");
return false;
}else {
ShowMessage(tr("save to %1 succeed").arg(file));
return image.save(file,"BMP");
如何才能使保存的文件自动带上格式而不需要手动输入