在QGraphicsView中播放图像序列(神秘内存泄漏) [英] Playing image sequence in QGraphicsView (Mysterious Memory Leak)
问题描述
我正在尝试处理图像序列,并使用OpenCV和PyQt5对结果进行视频处理.我有一些遍历目录的代码,读取图像,并尝试 将它们显示在QGraphicsView
上.
I'm trying to process an image sequence and make a video of the results using OpenCV and PyQt5. I've got some code that loops through a directory, reads in the images, and tries to display them on a QGraphicsView
.
def on_start(self):
for f in self.image_list:
img = cv2.imread(f)
img = cv2qimage(img, False)
self.scene.set_qimage(img)
self.scene
继承自QGraphicsScene
.
def set_qimage(self, qimage):
self.pixmap = QPixmap.fromImage(qimage)
self.addPixmap(self.pixmap)
问题在于,每次我调用addPixmap()
时,图像都被添加到所有其他图像的顶部,并且很快我的内存不足,一切都崩溃了.
当前代码不包含任何处理步骤,它只是将numpy ndarry转换为QImage并将QPixmap添加到场景中.
The problem is everytime I call addPixmap()
the image is just added on top of all the other images and soon I run out of memory and everything crashes.
The current code doesn't include any of the processing steps, it just converts the numpy ndarry to a QImage and adds the QPixmap to the scene.
什么是更新QGraphicsScene的正确方法,以便我可以流式传输图像序列?
推荐答案
每次使用addPixmap()
时,您都在创建新的QGraphicsPixmapItem
,不必要地增加了内存.解决方案是创建一个QGraphicsPixmapItem
并重新使用它.另外,处理任务可能会阻塞主线程,因此您必须使用线程来执行繁重的任务,并通过信号发送QImage
.
Every time you use addPixmap()
you are creating a new QGraphicsPixmapItem
adding memory unnecessarily. The solution is to create a QGraphicsPixmapItem
and reuse it. In addition the processing task can block the main thread so you must use a thread to do the heavy task and send the QImage
through signals.
class ProcessWorker(QObject):
imageChanged = pyqtSignal(QImage)
def doWork(self):
for f in self.image_list:
img = cv2.imread(f)
img = cv2qimage(img, False)
self.imageChanged.emit(img)
QThread.msleep(1)
class Widget(QWidget):
def __init__(self, parent=None):
QWidget.__init__(self, parent)
lay = QVBoxLayout(self)
gv = QGraphicsView()
lay.addWidget(gv)
scene = QGraphicsScene(self)
gv.setScene(scene)
self.pixmap_item = QGraphicsPixmapItem()
scene.addItem(self.pixmap_item)
self.workerThread = QThread()
self.worker = ProcessWorker()
self.worker.moveToThread(self.workerThread)
self.workerThread.finished.connect(self.worker.deleteLater)
self.workerThread.started.connect(self.worker.doWork)
self.worker.imageChanged.connect(self.setImage)
self.workerThread.start()
@pyqtSlot(QImage)
def setImage(self, image):
pixmap = QPixmap.fromImage(image)
self.pixmap_item.setPixmap(pixmap)
if __name__ == '__main__':
app = QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
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