1. Label "Any quadrilateral" or "Rectangular frame with angle" that meets these two conditions at the same time. I haven't seen it yet. Yolo_mark can only label horizontal rectangular boxes. Most of labelImage can only label horizontal rectangular boxes, and most of LabelImage It is python, it is not as easy to use as c++ exe.
2. The principle of drawing any quadrilateral: first draw a rectangular frame, and then adjust the four vertices (select one of the four vertices, principle: when the mouse falls on a few pixels near a certain vertex, it is considered that this vertex is selected, then You can perform some operations on this vertex).
3. The principle of selecting the quadrilateral: the mouse pointer falls into the quadrilateral, and the click event triggers the selection operation.
4. The principle of adjusting the angle of the rectangle: Select the rectangle and rotate it clockwise or counterclockwise by several angles with the center of the rectangle as the origin (in response to mouse or keyboard events).