Basic shapes

Before we start, let me introduce the Python code that we will use in most of this chapter's examples:

1. # File name: drawing.py
2. from kivy.app import App
3. from kivy.uix.relativelayout import RelativeLayout
4. 
5. class DrawingSpace(RelativeLayout):
6.   pass
7. 
8. class DrawingApp(App):
9.   def build(self):
10.     return DrawingSpace()
11. 
12. if __name__=="__main__":
13.   DrawingApp().run()

We have created the subclass DrawingSpace from RelativeLayout. We could have chosen any Widget but we are going to integrate some of these ideas into our comic creator project later on, it is best to use RelativeLayout which the comic creator uses as drawing space.

There are two types of instructions that we can add to a Canvas instance. These instructions are represented by two base classes: VertexInstructions and ContextInstructions.

Note

The VertexInstruction subclasses allows us to draw vector shapes in the coordinate space. The ContexInstruction classes let us apply changes...