title: How to interactively draw points onto a Pixmap that is on a QLabel in PyQT
body: <p>I am building a small GUI interface and I have a QLabel that draws images from a directory onto itself by setting them as the pixmap. I want the user to be able to interactively click points on this pixmap and have a small green 'x' appear at the clicked locations. I have tried re-implementing the paintEvent method, but this is not the functionality I want at all. paintEvent is what gets called every time there is a reason to paint on the QLabel... whereas I want to leave the base drawing (the image) alone and simply place points on top of the already-drawn image. Eventually, I am going to want the user to be able to interactively track these points through a sequence of images, using third-party tracking algorithms. Thus, I need the capability of having the user move points around, remove points, add points, and modify them without needing to re-draw the image behind them. There are several tutorials online about simply drawing points, but they all involve re-implementing the paintEvent method and then connecting a mouseEvent to the paintEvent. I am trying to specifically avoid this. Any suggestions?</p>