Kivy – Interactive Applications and Games in Python - Second Edition

Localizing coordinates – adding stickmen

In the last section, we used the to_parent() method (line 66) to translate the coordinates relative to the DrawingSpace, to its parent. Remember that we were inside DraggableWidget and the coordinates we received were relative to parent (DrawingSpace).

These coordinates are convenient for DraggableWidget because we positioned it in the parent's coordinates. The method allows us to use the coordinates in the parent's collide_point. This is no longer convenient for when we want to check the coordinates on the parent's parent space or when we need to draw something directly on the canvas of a Widget.

Before studying more examples, let's review the theory. You learned that RelativeLayout is very useful because ...