Principle of linear variable rectangle scaling矩形缩放原理运行图
"""
矩形缩放程序,本程序演示了矩形缩放原理。
"""
from turtle import *
def draw_rect(left,top,right,bottom):
"""根据左上角坐标和右下角坐标画矩形"""
width = right - left
height = top - bottom
t.goto(left,top)
t.pendown()
t.goto(left+width,top)
t.goto(right,bottom)
t.goto(left,top-height)
t.goto(left,top)
t.penup()
left,top = -20,10 # 左上角坐标
right,bottom = 20,-10 # 右下角坐标
width = right - left # 矩形宽度
height = top - bottom # 矩形高度
x0 = left + width/2 # 中心点x坐标
y0 = bottom + height/2 # 中心点y坐标
t = Turtle()
t.penup()
t.color('blue')
t.screen.delay(0)
draw_rect(left,top,right,bottom)
for scale in range(2,150): # 缩放比例
scale = scale / 10
x1 = x0 - 0.5 * width * scale
y1 = y0 + 0.5 * height * scale
x2 = x0 + 0.5 * width * scale
y2 = y0 - 0.5 * height * scale
draw_rect(x1,y1,x2,y2)
