旋转背景 PYQT5

Question

我正在尝试使用按钮旋转背景图像并在窗口上修剪图像，但它不起作用，我不知道为什么它不起作用。

但是当我按下按钮时，我的图像就消失了......

这是我的代码：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QGridLayout, QPushButton
from PyQt5.QtGui import QPixmap

class myApplication(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(myApplication, self).__init__(parent)

        self.img = QtGui.QImage()
        pixmap = QtGui.QPixmap("ola.png")
    

        self.label = QLabel(self)
        self.label.setMinimumSize(600, 600)
        self.label.setAlignment(QtCore.Qt.AlignCenter)
        self.label.setPixmap(pixmap)

        grid = QGridLayout()

        button = QPushButton('Rotate 15 degrees')
        button.clicked.connect(self.rotate_pixmap)

        grid.addWidget(self.label, 0, 0)
        grid.addWidget(button, 1, 0)

        self.setLayout(grid)

        self.rotation = 0

    def rotate_pixmap(self):

        pixmap = QtGui.QPixmap(self.img)
        self.rotation += 15

        transform = QtGui.QTransform().rotate(self.rotation)
        pixmap = pixmap.transformed(transform, QtCore.Qt.SmoothTransformation)

        self.label.setPixmap(pixmap)

if __name__ == '__main__':

    app = QApplication([])

    w = myApplication()  
    w.show()    

    sys.exit(app.exec_())

Answer 1

"self.img" 是一个空的 QImage 并且您正在旋转该元素。这个想法是旋转QPixmap：

class myApplication(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(myApplication, self).__init__(parent)

        self.rotation = 0

        self.pixmap = QtGui.QPixmap("ola.png")

        self.label = QLabel()
        self.label.setMinimumSize(600, 600)
        self.label.setAlignment(QtCore.Qt.AlignCenter)
        self.label.setPixmap(self.pixmap)

        button = QPushButton("Rotate 15 degrees")
        button.clicked.connect(self.rotate_pixmap)

        grid = QGridLayout(self)
        grid.addWidget(self.label, 0, 0)
        grid.addWidget(button, 1, 0)

    def rotate_pixmap(self):
        pixmap = self.pixmap.copy()
        self.rotation += 15
        transform = QtGui.QTransform().rotate(self.rotation)
        pixmap = pixmap.transformed(transform, QtCore.Qt.SmoothTransformation)
        self.label.setPixmap(pixmap)