先上效果图

代码

#!/usr/bin/env python

# coding=utf-8

from pylab import *

from matplotlib.ticker import MultipleLocator

import matplotlib.patches as patches

'''

1. 输入直线两端点 x0,y0 xn,yn

2. 计算初始值delta_x, delta_y,k=delta_y/delta_x,d=0, x=x0,y=y0

3. 绘制点x,y

4. d更新为d+k,若d>0.5,则x,y更新为x+1,y+1,d=d-1;否则x,y更新为x+1,y

5. 重复3,4直到直线画完

'''

def init(ax, width):

# 设置长宽

ax.axis([0, width, 0, width])

# 设置主刻度标签的位置,标签文本的格式

majorLocator = MultipleLocator(1)

minorLocator = MultipleLocator(0.5)

ax.xaxis.set_major_locator(majorLocator)

ax.yaxis.set_major_locator(majorLocator)

# ax.xaxis.set_minor_locator(minorLocator)

# ax.yaxis.set_minor_locator(minorLocator)

ax.grid(True) # x坐标轴的网格使用主刻度

def add_pixel(x, y, ax, c):

x = round(x)

y = round(y)

if c == 1:

ax.add_patch(patches.Rectangle((x - 0.5, y - 0.5), 1, 1, color='b'))

ax.plot(x, y, 'r.')

else:

ax.add_patch(patches.Rectangle((x - 0.5, y - 0.5), 1, 1))

ax.plot(x, y, 'y.')

if __name__ == '__main__':

# 将一行的字符串分割并转化为数字

x0, y0, x1, y1, width = map(int, input("输入直线的两点和画布的边长: ").split(' '))

if x0>x1:

x0,x1=x1,x0

y0,y1=y1,y0

ax = subplot(121, aspect='equal',

title='modified Bresenham') # 改进的bresenham

ax.plot([x0, x1], [y0, y1], '-k')

bx = subplot(122, aspect='equal', title='DDA') # DDA

bx.plot([x0, x1], [y0, y1], '-k')

# 图形初始化

init(ax, width)

init(bx, width)

delta_x = x1 - x0

delta_y = y1 - y0

d = 0

if delta_x == 0:

k = 999999999

else:

k = delta_y / delta_x

x = round(x0)

y = round(y0)

'''

DDA算法

'''

if k > -1 and k < 1:

# X 最大位移

while True:

if x > x1:

break

add_pixel(x, y, bx, 1)

x = x+1

y = y+k

elif k >= 1:

# Y 最大位移

while True:

if y > y1:

break

add_pixel(x, y, bx, 1)

y = y+1

x = x+1/k

else:

while True:

if y < y1:

break

add_pixel(x, y, bx, 1)

y = y-1

x = x-1/k

'''

k的范围

1. (0,1) x为最大位移，y正向增加

2. (1,+inf) y为最大位移，x正向增加

3. (0,-1) x为最大位移，y负向增加

4. (-1,-inf)y为最大位移，y减小。x正向增加

'''

x = x0

y = y0

if k > 1:

while True:

if y > y1:

break

add_pixel(x, y, ax, 0)

y = y + 1

d = d + 1 / k

if d > 0.5:

x = x + 1

d = d - 1

elif k > 0:

while True:

if x > x1:

break

add_pixel(x, y, ax, 0)

x = x + 1

d = d + k

if d > 0.5:

y = y + 1

d = d - 1

elif k > -1:

while True:

if x > x1:

break

add_pixel(x, y, ax, 0)

x = x + 1

d = d - k

if d > 0.5:

y = y - 1

d = d - 1

else:

while True:

if y < y1:

break

add_pixel(x, y, ax, 0)

y = y - 1

d = d - 1 / k

if d > 0.5:

x = x + 1

d = d - 1

show()