如何使用Python在像素网格中绘制圆形C((x,y),r)
,已知圆心(x,y)
和半径r
?假设像素网格足够大即可。
这是Python语言实现的RosettaCode中点圆算法
def circle(self, x0, y0, radius, colour=black):
f = 1 - radius
ddf_x = 1
ddf_y = -2 * radius
x = 0
y = radius
self.set(x0, y0 + radius, colour)
self.set(x0, y0 - radius, colour)
self.set(x0 + radius, y0, colour)
self.set(x0 - radius, y0, colour)
while x < y:
if f >= 0:
y -= 1
ddf_y += 2
f += ddf_y
x += 1
ddf_x += 2
f += ddf_x
self.set(x0 + x, y0 + y, colour)
self.set(x0 - x, y0 + y, colour)
self.set(x0 + x, y0 - y, colour)
self.set(x0 - x, y0 - y, colour)
self.set(x0 + y, y0 + x, colour)
self.set(x0 - y, y0 + x, colour)
self.set(x0 + y, y0 - x, colour)
self.set(x0 - y, y0 - x, colour)
Bitmap.circle = circle
bitmap = Bitmap(25,25)
bitmap.circle(x0=12, y0=12, radius=12)
bitmap.chardisplay()
from PIL import Image, ImageDraw
image = Image.new('1', (10, 10)) #create new image, 10x10 pixels, 1 bit per pixel
draw = ImageDraw.Draw(image)
draw.ellipse((2, 2, 8, 8), outline ='white')
print list(image.getdata())
输出:
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 255, 255, 0, 0, 0, 255, 255, 0, 0, 0, 255, 0, 0, 0, 0, 0, 255, 0, 0, 0, 255, 0, 0, 0, 0, 0, 255, 0, 0, 0, 255, 0, 0, 0, 0, 0, 255, 0, 0, 0, 255, 255, 0, 0, 0, 255, 255, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[x/255 for x in image.getdata()]
0
和1
的二维数组,其中1
表示圆的位置。 - user4175155