从QLabel获取QPixmap [英] Get the QPixmap from a QLabel

问题描述

我有一个 QLabel 调用图片其中 Pixmap 已设置为 QImage 。

我现在要在另一个函数中修改图像。

可以获取图片中的 Pixmap ？

I have a QLabel called Picture which Pixmap has been set to a QImage.
I now want to modify the image in another function.
Is it possible to get the Pixmapfrom the Picture?

我尝试下列操作，导致未处理的异常：

I tried the following, which results in an unhandled exception:

QPixmap const *pm = ui.Picture->pixmap();  
QImage image(pm->toImage());

有没有其他方法？

推荐答案

我想你会检查 pixmap（）函数的返回值。

I think you shall check the return value of the pixmap() function.

const QPixmap* pixmap = ui.Picture->pixmap();
if ( pixmap )
{
    QImage image( pixmap->toImage() );
}

也许你只是在图像未设置时调用函数，例外。

Maybe you just called the function when the image was not set and that caused the exception.

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