PIL ellipse函数画椭圆

该函数用于画椭圆。

函数原型ellipse(xy, fill=None, outline=None)

第一参数为椭圆的外切矩形， 当外切矩形是正方形时，形状为圆。xy指(x1, y1, x2, y2)可以看成是(left, top, right, bottom)

第二、三参数为填充颜色和线条颜色。

from PIL import Image
from PIL import ImageDraw

image = Image.open('1.jpg')
draw = ImageDraw.Draw(image)

draw.ellipse((590, 260, 620, 290), 'red')
image.show()

参考文献：
https://blog.csdn.net/guduruyu/article/details/71213717

所有颜色：

import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib.colors as colors
import math


fig = plt.figure()
ax = fig.add_subplot(111)

ratio = 1.0 / 3.0
count = math.ceil(math.sqrt(len(colors.cnames)))
x_count = count * ratio
y_count = count / ratio
x = 0
y = 0
w = 1 / x_count
h = 1 / y_count

for c in colors.cnames:
    pos = (x / x_count, y / y_count)
    ax.add_patch(patches.Rectangle(pos, w, h, color=c))
    ax.annotate(c, xy=pos)
    if y >= y_count-1:
        x += 1
        y = 0
    else:
        y += 1

plt.show()