turtle.py

import mathimport stringclass Turtle:    def __init__(self, model, theta):        self.model = model        self.theta = theta        self.margin = 0        self.x0 = 0        self.y0 = 0        self.alpha0 = 0            def draw(self, draw_line):        x = self.x0        y = self.y0        alpha = self.alpha0        stack = []                for l in self.model:            if l == "+": alpha += self.theta            elif l == "-": alpha -= self.theta            elif l in string.ascii_uppercase:                x_new = x + math.cos(alpha)                y_new = y + math.sin(alpha)                draw_line((x, y), (x_new, y_new))                x = x_new                y = y_new            elif l in string.ascii_lowercase:                x += math.cos(alpha)                y += math.sin(alpha)            elif l == "[": stack.append((x, y, alpha))            elif l == "]": x, y, alpha = stack.pop()    def get_bounds(self):        min = [0, 0]        max = [0, 0]        def update_bounds(p1, p2):            def upd_bounds(p):                x, y = p                if x > max[0]: max[0] = x                elif x < min[0]: min[0] = x                if y > max[1]: max[1] = y                elif y < min[1]: min[1] = y            upd_bounds(p1)            upd_bounds(p2)        self.draw(update_bounds)        return (min[0], min[1]), (max[0], max[1])    def get_scaling_fn(self, res):        min_b, max_b = self.get_bounds()        m2 = self.margin * 2        s = min((res[0] - m2) / (max_b[0] - min_b[0]), (res[1] - m2) / (max_b[1] - min_b[1]))        x0 = -min_b[0] * s        y0 = -min_b[1] * s        def scaling_fn(p):            x_scr = x0 + self.margin + p[0] * s            y_scr = y0 + self.margin + p[1] * s            return x_scr, y_scr        return scaling_fn