Question

我正在帧缓冲区中绘制一个蓝色矩形，我想再次擦除它。在绘制矩形之前，我先复制粘贴矩形的背景，然后在2秒钟后将其粘贴到矩形上。矩形不会被删除。

#!/usr/bin/env python

import numpy as np
import time
from PIL import Image
from io import BytesIO

h, w, c = 1024, 1280, 4
fb = np.memmap('/dev/fb0', dtype='uint8',mode='w+', shape=(h,w,c))
x0, y0 = 50, 200
w, h = 300, 400

# Copy backbround:      Does not work?
n0 = fb.read[y0:y0+h, x0:x0+w]

# Paste blue rectangle to framebuffer:      This works.
img = Image.new('RGBA', size=(w, h), color=(255,0,0,255))
n = np.array(img)
fb[y0:y0+h, x0:x0+w] = n

# Erase image:       Does not work?
time.sleep(2)
fb[y0:y0+h, x0:x0+w] = n0

我在做什么错？如果将n0粘贴到帧缓冲区的另一个位置，则会得到一个蓝色矩形，而不是黑色矩形。

Answer 1

我自己使用np.copy解决了该问题：

import numpy as np
import time
from PIL import Image

h, w, c = 1024, 1280, 4
fb = np.memmap('/dev/fb0', dtype='uint8',mode='w+', shape=(h,w,c))
x0, y0 = 50, 200
w, h = 300, 400

# Copy background:
### n0 = fb.read[y0:y0+h, x0:x0+w]
n0 = np.copy(fb[y0:y0+h, x0:x0+w])

# Paste blue rectangle to framebuffer:      This works.
img = Image.new('RGBA', size=(w, h), color=(255,0,0,255))
n = np.array(img)
fb[y0:y0+h, x0:x0+w] = n

# Erase image:
time.sleep(2)
### fb[y0:y0+h, x0:x0+w] = n0
fb[y0:y0+h, x0:x0+w] = np.copy(n0)

复制并粘贴到帧缓冲区

1 个答案: