Table Of Contents
Drawing¶
Each widget has a canvas, i.e. a place to draw on. The canvas is a group of drawing instructions that should be executed whenever there is a change to the widget’s graphical representation.
You can add two types of instructions to the canvas: context instructions and vertex instructions. You can add instructions either from Python code or from the kv file (the preferred way). If you add them via the kv file, the advantage is that they are automatically updated when any property they depend on changes. In Python, you need to do this yourself.
In both cases, the canvas of MyWidget is re-drawn whenever the position
or the size of the widget changes.
You can use the
canvas.before or
canvas.after groups to separate
your instructions based on when you want them to be executed.
For an in-depth look at how Kivy’s graphics are handled, look
here.