Re: [DIGImend-users] Huion 610p tablet and hardware buttons

[<co...@pi...>]

Dear Alec,

Some times ago, I had a discussion with someone on how to map the button 
of the tablet, here is the solution we came up with :

(a little disclaimer: I am not exactly a computer scientist and I have 
managed to make the key "work" but it is not really clean and I won't be 
able to explain every step in depth ^^.
A documentation that has helped me a lot is available on the arch wiki : 
https://wiki.archlinux.org/index.php/Map_scancodes_to_keycodes)

Anyway, here is the full process I have followed :
1. First, you need to identify the vendor_id and product_id of your 
tablet by looking for it in the usb device list (with the 'lsusb' 
command), my vendor ID is 256C and my product ID is 006E. I guess they 
are the same for you but you may want to check.
2. Then, you can create the .hwdb file containing your rules in 
/etc/udev/hwdb.d
I have called mine huion.hwdb
Before writing the rules for the tablet, you need to specify that those 
rules will apply to this device by specifying its ID as :
keyboard:usb:v256Cp006E*
  KEYBOARD_KEY_700e0=unknown # This is a rule, see below

After the first line, each rule line begins with a space. A rule is 
defined on the left of the equality by the input key and on the right by 
the new key you want to have.
3. To identify scancodes, I have used the command 'evtest' in root. It 
asks you to choose the right device, for some reasons I had several 
huion tablet listed, so I tried them all and used the one that actually 
responded to the input buttons.
You can find in the attached file the output I get when I press the 
eraser button.
The first 5 lines seem to be triggered by the push down of the button 
and the last 5 ones by the release.

The first line say that the first key to be pressed has the code 700e1 
and the following line tells us that it is LEFT_SHIFT.
Then the two following lines say that the key KPMINUS is pressed and its 
code is 70056
Hence, by default, pressing the eraser button leads to "shift"+ "-" 
which is not exactly what I want. And by testing the other buttons you 
will see that each one uses some key modifier like Alt or Ctrl.

4. Now that you have identified the inputs associated to this button, 
you can remap it in your .hwdb file
--> From this point I have made very personal choices that you may want 
to change ^^
I have decided to get rid of the modifier keys "shift", "alt" and "ctrl" 
so I have first mapped them to the key "rightctrl" (I did not find a way 
to completely discard these inputs), and then I have assigned the other 
inputs to key that are not on my keyboard : f13->f21

Here is my .hwdb file :

keyboard:usb:v256Cp006E*
  KEYBOARD_KEY_700e0=rightctrl # map ctrl to something useless like 
rightctrl
  KEYBOARD_KEY_700e1=rightctrl # shift -> rightctrl
  KEYBOARD_KEY_700e2=rightctrl # alt -> rightctrl
  KEYBOARD_KEY_7003d=f13 # back button -> f13
  KEYBOARD_KEY_70016=f14 # eraser --> f14
  KEYBOARD_KEY_70056=f15 # pencil --> f15
  KEYBOARD_KEY_70057=f16 # + --> f16
  KEYBOARD_KEY_7000a=f17 # - -->f17
  KEYBOARD_KEY_70019=f18 # pencil + --> f18
  KEYBOARD_KEY_7001b=f21 # pencil - --> f21
  KEYBOARD_KEY_70006=f20 # hand --> f20

I have assigned the inputs to keys that are not on my keyboard to be 
able to use the same button for different shortcut depending on the used 
application by using "autokey" which enables to remap (again...) keys to 
others depending on the current application.

(For autokey, see for instance 
http://www.howtogeek.com/howto/26913/how-to-customize-shortcut-keys-for-any-linux-application/ 
)

5. to load the rules you must do (as root) :

udevadm hwdb --update
udevadm trigger

6. You can check your rules by launching evtest again.

I think that there is a cleaner way to proceed, especially concerning 
the modifier keys, but it seems to work...
I hope this helps!


Le 25.03.2015 14:39, Alec Teal a écrit :
> I hate to do this but it's been 5 days and now all I'm finding from
> search results are my own questions.
> 
> This is not an area I've ever had to deal with (anything with the 
> letter
> x infront of it that is) but I really need at least an undo button.
> 
> I did try with xbindkeys, but I don't want to remap "normal" keyboard
> shortcuts and Gimp doesn't recognise that the tablet has hardware 
> buttons.
> 
> Also the undo button (top one, causes active window to [attempt] to
> close) causes a segfault with xbindkeys -k which is really weird.
> 
> Anyway how can I help fix this? I really need that undo button.
> 
> Thanks,
> 
> Alec
> 
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