传递 4 元组 RGBA 值,而不是 3 元组 RGB 值 (255, 128, 10):
canvas.ellipse((p_x - 5, p_y - 5, p_x + 5, p_y + 5),
fill=(255, 128, 10, 50))
例如,
import Image
import ImageDraw
img = Image.new('RGBA', size = (100, 100), color = (128, 128, 128, 255))
canvas = ImageDraw.Draw(img)
# Now I draw the circle:
p_x, p_y = 50, 50
canvas.ellipse((p_x - 5, p_y - 5, p_x + 5, p_y + 5), fill=(255, 128, 10, 50))
# now save and close
del canvas
img.save('/tmp/test.png', 'PNG')
![enter image description here](https://i.stack.imgur.com/ATdwP.png)