Proof of concept of working key handling

huion_keys.py

@@ -0,0 +1,81 @@
+from _xdo_cffi import ffi, lib
+
+BUTTON_BINDINGS = [
+    # left side, top to bottom
+    None,
+    None,
+    None,
+    None,
+
+    b'a',
+    b'b',
+    b'c',
+    b'd',
+
+    # right side, top to bottom
+    None,
+    None,
+    None,
+    None,
+
+    b'e',
+    b'f',
+    b'g',
+    b'h',
+
+    # scroll strip, up/down
+    # even though the Kamvas 22 (2019) has two scroll strips, they both send
+    # the same button codes
+    None,
+    None,
+]
+
+def main():
+    xdo = lib.xdo_new(ffi.NULL)
+    hidraw_path = get_tablet_hidraw()
+    hidraw = open(hidraw_path, 'rb')
+    while True:
+        btn = get_button_press(hidraw)
+        print("Got button %d" % (btn,))
+        if BUTTON_BINDINGS[btn]:
+            lib.xdo_send_keysequence_window(
+                xdo, lib.CURRENTWINDOW, BUTTON_BINDINGS[btn], 10)
+
+
+def get_tablet_hidraw():
+    return '/dev/hidraw3'
+
+
+BUTTON_BITS = {
+    0x01: 0,
+    0x02: 1,
+    0x04: 2,
+    0x08: 3,
+    0x10: 4,
+    0x20: 5,
+    0x40: 6,
+    0x80: 7,
+}
+
+def get_button_press(hidraw):
+    while True:
+        sequence = hidraw.read(12)
+        # don't think there's anything we care about that doesn't start with 0xf7
+        if sequence[0] != 0xf7:
+            pass
+        if sequence[1] == 0xe0: # buttons
+            # doesn't seem like the tablet will let you push two buttons at once
+            if sequence[4] > 0:
+                return BUTTON_BITS[sequence[4]]
+            elif sequence[5] > 0:
+                # right-side buttons are 8-15, so add 8
+                return BUTTON_BITS[sequence[5]] + 8
+            else:
+                # must be button release (all zeros)
+                continue
+        elif sequence[1] == 0xf0: # scroll strip
+            pass # TODO: implement this
+
+
+if __name__ == "__main__":
+    main()

xdo_test.py

@@ -4,7 +4,8 @@ from _xdo_cffi import ffi, lib
 
 X = 200
 
+# should make mouse cursor walk across screen
 xdo = lib.xdo_new(ffi.NULL)
-for i in range(20):
+for i in range(15):
     lib.xdo_move_mouse(xdo, X * i, 500, 0)
     time.sleep(0.1)