色块反色

我的控制台背景是白的...

README.md

@@ -69,6 +69,12 @@ itchat.auto_login(enableCmdQR = True)
 itchat.auto_login(enableCmdQR = 2)
 ```
 
+默认控制台背景色为暗色（黑色），若背景色为浅色（白色），可以将enableCmdQR赋值为负值：
+
+```python
+itchat.auto_login(enableCmdQR = -1)
+```
+
 ### 退出程序后暂存登陆状态
 
 通过如下命令登陆，即使程序关闭，一定时间内重新开启也可以不用重新扫码。

README.rst

@@ -71,6 +71,12 @@ Because of width of some character differs from systems, you may adjust the enab
     # for some linux system, width of block character is one instead of two, so enableCmdQR should be 2
     itchat.auto_login(enableCmdQR = 2)
 
+Default background color of command line is dark (black), if it's not, you may set enableCmdQR to be negative:
+
+.. code:: python
+
+    itchat.auto_login(enableCmdQR = -1)
+
 *Hot reload*
 
 By using the following command, you may reload the program without re-scan QRCode in some time.

README_EN.md

@@ -68,6 +68,12 @@ Because of width of some character differs from systems, you may adjust the enab
 itchat.auto_login(enableCmdQR = 2)
 ```
 
+Default background color of command line is dark (black), if it's not, you may set enableCmdQR to be negative:
+
+```python
+itchat.auto_login(enableCmdQR = -1)
+```
+
 ### Hot reload
 
 By using the following command, you may reload the program without re-scan QRCode in some time.

itchat/tools.py

@@ -63,19 +63,20 @@ def print_qr(fileDir):
     else:
         os.startfile(fileDir)
 try:
-    from PIL import Image 
+    from PIL import Image
     def print_cmd_qr(fileDir, size = 37, padding = 3,
             white = BLOCK, black = '  ', enableCmdQR = True):
         img     = Image.open(fileDir)
         times   = img.size[0] / (size + padding * 2)
         rgb     = img.convert('RGB')
         try:
             blockCount = int(enableCmdQR)
-            assert(0 < blockCount)
+            assert(0 < abs(blockCount))
         except:
             blockCount = 1
         finally:
-            white *= blockCount
+            white *= abs(blockCount)
+            if blockCount < 0: white, black = black, white
         sys.stdout.write(' '*50 + '\r')
         sys.stdout.flush()
         qr = white * (size + 2) + '\n'