More Drawing Tools ( Canvas class; Curves) www.cis.syr.edu/~mohan/gra6.ppt Canvas class Provides simple methods for creating screen window, establishing world window, mapping them, and simple Turtle graphics routines (moveto, lineto,…) Supporting classes:
( Canvas class; Curves)
using default values for all parameters.
These functions make it easy to build complex drawings from simple ones.
forward(len, 1); turn(angle); len += increment;
Graphics shapes can be described in many ways, each with its own [dis]advantages:
x(t)=A.x +(B.x-A.x)t, y(t)= A.y+(B.y-A.y)t
x(t)=W cos(t), y(t)= H sin (t)
To extract implicit form, we would have to eliminate the parameter t from the equations.
Parametric forms specified using three functions x(t), y(t), z(t), e.g.,
x(t)=(a sin(ct) +b) cos(t),
y(t)=(a sin(ct) +b) sin(t), z(t)= a cos (ct)