我有一个PyQt代码,它不断崩溃,给我错误消息QPixmap::fromImage: QPixmap cannot be created without a QGuiApplication QPixmap: Must construct a QGuiApplication before a QPixmap
这是一个相当简单的应用程序,我从一个名为CameraWidget
的类中读取帧,并应用函数def transform_perspective(self, frame, points)
来获取该帧的变换透视图。我将屏幕分成两个相等的部分,右半部分显示相机看到的帧,左半部分显示它的透视变换(我从另一个名为Canvas
的类获取坐标)
还有一个问题:左半部分并没有占据整个区域。很多部分都是黑色的。这是一张照片供你参考
这是一个相当长的课程,所以下面我将包括我认为问题所在的课程
class TopView(QtWidgets.QWidget):
def __init__(self, parent=None):
super(TopView, self).__init__(parent)
self.original_frame = CameraWidget('Abc.ts')
# Layouts and frames
self.frame = QtWidgets.QFrame()
layout = QtWidgets.QVBoxLayout()
layout.addWidget(self.frame)
layout.setContentsMargins(0,0,0,0)
layout.setSpacing(0)
self.setLayout(layout)
# frame left
self.frame_left = QtWidgets.QFrame()
self.get_frame_thread = Thread(target=self.transform_frame, args=())
self.get_frame_thread.daemon = True
self.get_frame_thread.start()
self.top_view_label = QtWidgets.QLabel()
self.top_view_label.setScaledContents(True)
self.layout_left = QtWidgets.QVBoxLayout()
self.layout_left.addWidget(self.top_view_label)
self.layout_left.setContentsMargins(0,0,0,0)
self.layout_left.setSpacing(0)
self.frame_left.setLayout(self.layout_left)
# frame right
self.frame_right = QtWidgets.QFrame()
self.frame_right.setStyleSheet("background-color: rgb(153, 187, 255)")
self.video_frame_1 = self.original_frame
# Create camera widgets
print('Creating Camera Widgets...')
self.layout_right = QtWidgets.QVBoxLayout()
self.layout_right.addWidget(self.video_frame_1)
self.layout_right.setContentsMargins(5,5,5,5)
self.frame_right.setLayout(self.layout_right)
self.layout_inner = QtWidgets.QHBoxLayout()
self.layout_inner.addWidget(self.frame_left, 50)
self.layout_inner.addWidget(self.frame_right, 50)
self.layout_inner.setContentsMargins(0,0,0,0)
self.layout_inner.setSpacing(0)
self.frame.setLayout(self.layout_inner)
self.setLayout(layout)
sizeObject = QtWidgets.QDesktopWidget().screenGeometry(0)
self.screen_width = int(0.7*sizeObject.width())
self.screen_height = int(0.7*sizeObject.height())
def event(self, e):
if e.type() in (QtCore.QEvent.Show, QtCore.QEvent.Resize):
print('')
return QtWidgets.QWidget.event(self, e)
def transform_frame(self):
while True:
try:
self.top_view_frame = self.transform_perspective(self.original_frame.get_video_frame(), self.original_frame.canvas.mapped_list)
h, w, ch = self.top_view_frame.shape
bytesPerLine = ch * w
self.img = QtGui.QImage(self.top_view_frame, w, h, bytesPerLine, QtGui.QImage.Format_RGB888)
self.pix = QtGui.QPixmap.fromImage(self.img)
if not sip.isdeleted(self.top_view_label):
self.top_view_label.setPixmap(self.pix)
except Exception as e:
print(e)
def transform_perspective(self, frame, points):
points = np.float32(points)
p2 = np.float32([[0, 0], [600, 0], [0, 600], [600, 600]])
self.matrix = cv2.getPerspectiveTransform(points, p2)
frame = cv2.warpPerspective(frame, self.matrix, (400, 600))
return frame
尽管OP没有提供MRE,但很容易注意到错误在于它正在禁止的次线程中创建QPixmap。相反,您应该将QImage发送到GUI线程,并在GUI线程中将其转换为QPixmap:
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