问题
Suppose I have drawn simple text (say just the letter 'x') with some font parameters (like size 20 font, etc.) onto an (x,y) location in a QLabel that holds a QPixmap. What are the relevant methods that I will need to override in order to detect a mouse event when a click occurs "precisely" over one of these drawn x's.
My first instinct is to lookup the stored (x,y) locations of drawn points and if the mouse current position is inside a tiny box around that (x,y) position, then I will execute some functionality, like allowing the user to adjust that point, and if not then execute normal mouse event functionality. However, the points I am interacting with are tracked features on human faces, like eyes, etc. Often, when someone is turning at an odd angle with the camera, etc., two distinct tracked points can be pretty much right on top of each other. Thus, no matter how well the user focuses on the desired key point, if there is some tolerance in the logic criteria in mouse event handling, there will be cases where the logic believes two different points are being clicked.
I want to minimize this sort of issue without making unreasonable precision of the click criteria. Is there some fundamentally different way to interpret selection of text (as in, when text is drawn to a pixmap, does there become any sort of attribute of that pixmap that is aware that text has been drawn at (x,y) and so that's what the user must be trying to click on?)
Any advice or examples of this sort of thing in PyQT would be greatly appreciated.
回答1:
Although you alluded to your plans for user interaction in your previous question, it is now clear that the Graphics View Framework may be more appropriate for what you are trying to do.
This is distinctly different from drawing in a widget. With this framework, you create a scene composed of graphic items (QGraphicsItem subclasses) and then assigne the scene to a view. Through the view, you can interact with the items in the scene. They can generate click events and even be dragged around. The documentation is extensive and looks complicated but conceptually, I think it is easier to understand.
来源：https://stackoverflow.com/questions/6222044/python-pyqt-how-to-detect-mouse-events-when-clicking-text-points-in-a-pixmap