1. LING 408/508: Programming for Linguists Lecture 23 November 25 th

2. Last Time Library graphics.py – built on top of Tkinter (Python interface to Tk) – built on top of Tk (graphics library) – built on top of X11 (graphics library) on Ubuntu

3. graphics.py

4. Object inheritance (see graphics.py code): GraphicsObject – Point: draw, move, clone – Text: clone, move, draw, setText, getText, setFace – Polygon: clone, getPoints, move, draw – _Bbox: move Rectangle: draw Oval: clone, draw – Circle: clone, getRadius Line: clone, draw, setArrow

5. Directly in wish tcl/tk Stylistic variation… graphics.py : use primitive object Point tk : uses plain x,y coordinates

6. Interactive Graphics textbook 5.7: –p = win.getMouse() returns a Point

7. Interactive Graphics

9. textbook 5.7: –input = Entry(center,width) creates a user- editable text box

10. Interactive Graphics

12. graphics.py API

15. Color: Color names: – see http://wiki.tcl.tk/37701http://wiki.tcl.tk/37701

16. graphics.py API

21. Section 6.2-6.4 Happy birthday example nested function calls: Note: parameters are passed by value (copying) -not by reference (pointer) -(some other programming languages allow both options)

22. Section 6.5 To send a value back, use – return Multiple values can be returned: Note: None is returned when there is no return statement

23. triangle2.py Calculates the perimeter of a triangle you draw.

24. triangle2.py Note: parameters are passed by value (copying) -mutable objects (Point)

25. triangle2.py