Keyboard Mouse

kbm.py

# - A first approximation of using the keyboard as a trackpad
# - It uses curses/Xlib for input and mouse interaction, so if you don't
#   have those you're going to have a bad time
# - This is only a proof of concept, sniffing X for keystrokes and
#   finding out how to seamlessly pop in and out of
#   keyboard-as-trackpad-mode is left as an exercise to the reader
# - It turns out this isn't a very good control scheme, given the
#   limited vertical resolution (4-6 rows vs. ~12 columns), and that
#   it additionally suffers from all the problems inherent in
#   acceleration based control schemes
# - You will have to edit KEYBOARD_MAP to suit your own keyboard: I
#   use a dvorak layout, so it is unlikely to fit your
#   layout. Creating a program to automatically create the map from a
#   photo of a keyboard is left as an exercise to the reader
#
# "THE BEER-WARE LICENSE" (Revision 42):
# <thenoviceoof> wrote this file. As long as you retain this notice
# you can do whatever you want with this stuff. If we meet some day,
# and you think this stuff is worth it, you can buy me a beer in
# return
# - thenoviceoof

import curses
import math

import time
import traceback

import Xlib
from Xlib import display

DISPLAY = display.Display()

def move_mouse_x(x,y):
    DISPLAY.warp_pointer(x,y)
    DISPLAY.sync()
    
def dist(a, b):
    return ((a[0]-b[0])**2 + (a[1]-b[1])**2)**0.5

def drag(dx,dy):
    v = (dx**2 + dy**2)**0.5
    ang = math.atan2(dy,dx)
    v *= 0.9
    # threshold the velocity
    if v < 0.5:
        v = 0
    dx = v * math.cos(ang)
    dy = v * math.sin(ang)
    return dx,dy

KEYBOARD_MAP = {
    '1': (-0.3,-1),
    '2': (0.6,-1),
    '3': (1.6,-1),
    '4': (2.6,-1),
    '5': (3.6,-1),
    '6': (4.6,-1),
    '7': (5.6,-1),
    '8': (6.6,-1),
    '9': (7.6,-1),
    '0': (8.6,-1),
    '[': (9.6,-1),
    ']': (10.6,-1),

    '\'': (0,0),
    ',': (1,0),
    '.': (2,0),
    'p': (3,0),
    'y': (4,0),
    'f': (5,0),
    'g': (6,0),
    'c': (7,0),
    'r': (8,0),
    'l': (9,0),
    '/': (10,0),
    '=': (11,0),

    'a': (0.3,1),
    'o': (1.3,1),
    'e': (2.3,1),
    'u': (3.3,1),
    'i': (4.3,1),
    'd': (5.3,1),
    'h': (6.3,1),
    't': (7.3,1),
    'n': (8.3,1),
    's': (9.3,1),
    '-': (10.3,1),

    ';': (0.6,2),
    'q': (1.6,2),
    'j': (2.6,2),
    'k': (3.6,2),
    'x': (4.6,2),
    'b': (5.6,2),
    'm': (6.6,2),
    'w': (7.6,2),
    'v': (8.6,2),
    'z': (9.6,2),
}

def main():
    # velocity
    dx = 0
    dy = 0
    # previous keyboard position for acceleration
    prev = None
    prev_time = None
    # set up curses
    stdscr = curses.initscr()
    curses.cbreak()
    stdscr.nodelay(1)
    char = None
    while 1:
        # grab keystrokes
        char = stdscr.getch()
        # turn them into acceleration
        if char != -1 and chr(char) in KEYBOARD_MAP:
            t = time.time()
            char = chr(char)
            x,y = KEYBOARD_MAP[char]
            if prev and dist(prev, (x,y)) > 1.5:
                # assume this is the user picking up and moving their
                # finger
                dx, dy = 0, 0
            elif prev:
                # accelerate them over that away
                dx += (x - prev[0]) / (t - prev_time)
                dy += (y - prev[1]) / (t - prev_time)
            prev = (x,y)
            prev_time = t
        # move the mouse according to the velocity
        move_mouse_x(dx,dy)
        # decelerate the movement
        dx,dy = drag(dx,dy)
        time.sleep(0.02)

if __name__ == '__main__':
    try:
        main()
    except Exception, e:
        # clean up after curses
        curses.nocbreak()
        curses.endwin()
        # re-raising an exception is annoyingly opaque
        traceback.print_exc()