PyQt - 如何覆盖图像上的矩形

Question

在PyQt标签上显示图像后，我想在显示的图像上绘制一个矩形。请注意，我并不是指用户在图像上“绘制”矩形的地方绘制的，而是指我只是想在图像上创建一个矩形。我有matplotlib轴的等效代码，但我不知道如何在PyQt中做同样的事情。

# Create Figure/Axes Instance 
figure,axes = matplotlib.pyplot.subplots() 
axes.imshow(imageRGB) 

# Draw Rectangle 
axes.add_patch(matplotlib.patches.Rectangle((50,50),100,100,fill=False,edgecolor='red')) 

Answer 1

# convert image file into pixmap 
self.pixmap_image = QtGui.QPixmap(self.filename) 

# create painter instance with pixmap 
self.painterInstance = QtGui.QPainter(self.pixmap_image) 

# set rectangle color and thickness 
self.penRectangle = QtGui.QPen(QtCore.Qt.red) 
self.penRedBorder.setWidth(3) 

# draw rectangle on painter 
self.painterInstance.setPen(self.penRectangle) 
self.painterInstance.drawRect(xPos,yPos,xLen,yLen) 

# set pixmap onto the label widget 
self.ui.label_imageDisplay.setPixmap(self.pixmap_image) 
self.ui.label_imageDisplay.show()