Custom tap sequence handling

Describe the bug
Sometimes my custom tap sequence gestures do not trigger, and I have finally identified the cause. When I place my hand on the trackpad, my fingertips do not lie in a straight line. Instead, they form an arc (or trapezoid shape, see screenshots below).

When using my laptop on my lap or on a table in front of me, the natural resting angle of my arm causes the arc of my fingertips to be rotated substantially to the left. I am right-handed, so when my right elbow is bent, my right hand points to the left.

The result of this is that my middle finger is almost directly above (in front of) my index finger on the trackpad, and sometimes it is slightly to the left. When that happens, BetterTouchTool interprets my middle finger tap as being in the furthest left position, instead of being the 2nd finger from the left.

Affected input device:
MacBook Pro trackpad

Here are some examples of my natural finger positions on the trackpad, taken as screenshots from the BetterTouchTool Live View window:

Notice that in the 1st and 3rd images, my middle finger (2nd from bottom) is further left than my index finger (bottom).

If my computer is further in front of me, the angle is different and the problem does not occur:

Device information:

  • Type of Mac: MacBook Pro
  • macOS version: 10.14.6
  • BetterTouchTool version: 3.206, but this has been an ongoing issue for a long time, it’s just that I only recently discovered the cause.

The behavior I would prefer is for BTT custom tap sequences to recognize finger position in terms of angle, that is clockwise or counterclockwise, instead of strictly left-to-right position. That way the same movement of fingers will trigger the same gesture regardless of how my arm is oriented.

This applies to 3-finger tap sequences and tip-taps as well. My middle finger is further forward than my index and ring finger, so their positions form an arc too:

It also applies for left-handed usage: with all the finger positions mirrored horizontally, the taps still form an arc and custom sequences should be recognized in terms of clockwise and counterclockwise angle.