Qt - 如何在QLabel图片上设置文本

Question

我认为需要使用QPainter，但我不知道如何将它们结合起来。

QLabel* imageLabel = new QLabel();
QImage image("c://image.png");
imageLabel->setPixmap(QPixmap::fromImage(image));
imageLabel->setAlignment(Qt::AlignCenter);

QPainter* painter = new QPainter();
painter->setPen(Qt::blue);
painter->setFont(QFont("Arial", 30));
painter->drawText(rect(), Qt::AlignCenter, "Text on Image");

- user375566

Answer 1

您需要告诉画家在哪里绘制：

QImage image("c://image.png");

// tell the painter to draw on the QImage
QPainter* painter = new QPainter(&image); // sorry i forgot the "&"
painter->setPen(Qt::blue);
painter->setFont(QFont("Arial", 30));
// you probably want the to draw the text to the rect of the image
painter->drawText(image.rect(), Qt::AlignCenter, "Text on Image");

QLabel* imageLabel = new QLabel();
imageLabel->setPixmap(QPixmap::fromImage(image));
imageLabel->setAlignment(Qt::AlignCenter);

- bjoernz

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这个不起作用。"没有匹配函数调用QPainter::QPainter（QImage&）"。 - user375566

候选者是QPainter :: QPainter（QPaintDevice *）...... 构造函数期望一个指针，因此您需要将图像的地址传递给构造函数。 - bjoernz

在图像上绘制还是覆盖QTextLabel更快？ - user1767754