arrow keys not being sent to readkey() #20

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1. suresttexas00

   changed the title [-]Usage info for readchar() of arrow keys[/-] [+]arrow keys not being sent to readkey()[/+] on Nov 27, 2016
2. guiweber commented on Mar 10, 2017

   

   guiweber

   on Mar 10, 2017

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   @suresttexas00 Have you tried if the arrows work with the code in PR #13 ? I remember I fixed that for at least Windows, but I might have fixed it for linux as well... I can't remember.
3. suresttexas00 commented on Mar 10, 2017

   

   suresttexas00

   on Mar 10, 2017

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   I'm working on testing that now. So far, all I know is that nothing is broken :P
4. suresttexas00 commented on Mar 10, 2017

   

   suresttexas00

   on Mar 10, 2017

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   # -*- coding: utf-8 -*-
   import readchar
   
   while True:
       keypress = readchar.readkey()
       print(keypress)
       if keypress in (readchar.key.CR, readchar.key.CTRL_C):
           break
   

   UP, RIGHT, DOWN, LEFT produces:

   ^[[B^[[D
   

   It is entirely random (Somewhere between the 1st and 3rd keypress) when a ^[[* character is printed. I am sure there might be a pattern that a gifted autistic might note; but I suck and it seems random to me :)
5. guiweber commented on Mar 10, 2017

   

   guiweber

   on Mar 10, 2017

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   The way special characters can be printed under Linux at the moment is different than on Windows. Try the following before anything else. Maybe it actually works:

   # -*- coding: utf-8 -*-
   import readchar
   
   while True:
       keypress = readchar.readkey()
       if keypress == readchar.key.UP:
           print("UP")
       elif keypress == readchar.key.DOWN:
           print("DOWN")
       elif keypress == readchar.key.LEFT:
           print("LEFT")
       elif keypress == readchar.key.RIGHT:
           print("RIGHT")
       elif keypress in (readchar.key.CR, readchar.key.CTRL_C):
           break
   

   If not, you probably need to look at the raw values returned by the following function in order to fix the arrows on linux
   char = os.read(sys.stdin.fileno(), 1)

   You might need more than one call to this function to get all the data from a single key press. Maybe there is a missing escape sequence in key.py that prevents getting the arrows.
6. suresttexas00 commented on Mar 10, 2017

   

   suresttexas00

   on Mar 10, 2017

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   I rewrote readchar_linux.py using the same logic and it now appears to detect the arrow keys now:

   import sys
   import os
   import select
   import tty
   import termios
   from . import key
   
   
   def readchar(wait_for_char=True):
       old_settings = termios.tcgetattr(sys.stdin)
       tty.setcbreak(sys.stdin.fileno())
       charbuffer = ''
   
       while True:
           char1 = getkey(wait_for_char, old_settings)
           if (charbuffer + char1) not in key.ESCAPE_SEQUENCES:
               return charbuffer + char1
           charbuffer += char1
   
   
   def getkey(wait_for_char, old_settings):
       charbuffer = ''
       try:
           if wait_for_char or select.select([sys.stdin, ], [], [], 0.0)[0]:
               char = os.read(sys.stdin.fileno(), 1)
               charbuffer = char if type(char) is str else char.decode()
       except Exception:
           pass
       finally:
           termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_settings)
       return charbuffer
   

   I'm sure that could be a little cleaner.. like I am not sure the wait_for_char argument is needed (or even the whole try:except) since readchar is not calling instances of itself here.
7. suresttexas00 commented on Mar 10, 2017

   

   suresttexas00

   on Mar 10, 2017

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   The next step would be to take these linux constants and map them to the same readable string values you are using in the windows version, so that they will compare equally on either system.

   have in keys.py:

   linux_keys = {
       # Single keys:
       UP: 'up',
       RIGHT: 'right',
   ...
   

   and then have the charbuffer scrubbed to replace:

   if charbuffer in linux_keys:
       return linux_keys[charbuffer]
   ...
   
8. suresttexas00 commented on Mar 14, 2017

   

   suresttexas00

   on Mar 14, 2017

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   Release 0.8
9. suresttexas00

   closed this as completedon Mar 14, 2017
10. magmax commented on Mar 14, 2017

    

    magmax

    on Mar 14, 2017

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    Release 1.0 tried to manage ESC key, but it is very confusing and obfuscate the code a lot. So I backtrack to 0.7 with some minor changes, where arrow keys were working fine.

    Thank you anyways for your effort.
11. suresttexas00 commented on Mar 15, 2017

    

    suresttexas00

    on Mar 15, 2017

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    got a new pull request based on my comment about # 1 fix above (so # 2 is still an issue - cant' get Esc key by itself or F11/F12.
12. suresttexas00 commented on Mar 15, 2017

    

    suresttexas00

    on Mar 15, 2017

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    I could probably fix that too, but it might break the windows part... and I own no windoze machines to test! :)