Qt QPixmap QPainter问题

发布于 2024-10-17 01:47:53 字数 520 浏览 4 评论 0原文

我有一段代码，其中包含以下代码行：

int dsize = 100;
QPainter *painter;
QPixmap *img;
QLabel *l_img;

painter = new QPainter;
img = new QPixmap(dsize, dsize);

l_img = new QLabel;
l_img->setPixmap(*img);

painter->begin(img);
painter->fillRect(img->rect(), Qt::white);

QPen pen(Qt::black, 12);
painter->setPen(pen);
painter->drawLine(40, 40, 40, 100);

painter->end();
l_img->show();

然而，当我运行代码时，我没有看到任何带有黑色矩形的白色图像。事实上我看到的是用大字体写的窗口标题。似乎没什么用，我只是得到了这样的图像。我做错了什么？

谢谢你！

原文

I have a piece of code that has this lines of code:

int dsize = 100;
QPainter *painter;
QPixmap *img;
QLabel *l_img;

painter = new QPainter;
img = new QPixmap(dsize, dsize);

l_img = new QLabel;
l_img->setPixmap(*img);

painter->begin(img);
painter->fillRect(img->rect(), Qt::white);

QPen pen(Qt::black, 12);
painter->setPen(pen);
painter->drawLine(40, 40, 40, 100);

painter->end();
l_img->show();

How ever when I run the code, I don't see any white image with a black rectangle on it. In fact what I see is the title of the window written in big fonts. Nothing seems to work, I just get an image like that. What am I doing wrong?

Thank you!

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