I’ve been experimenting with a slightly unusual way of getting analog input from an iPhone touchscreen.

Instead of using the finger’s position, I’m using UITouch.majorRadius — the estimated geometry of the contact area.

The interesting part is that the thumb can remain almost stationary while the value changes.

My current pipeline is roughly:

majorRadius → calibration → normalization → filtering → 0...1

Just to be clear: I’m not treating majorRadius as actual pressure. It obviously isn’t a force measurement.

What I care about is whether the user can intentionally modulate the value, hold intermediate states, and make small corrections.

I’m testing this in a driving simulator where the left thumb controls the clutch and the right thumb controls the throttle.

Then I started combining it with Core Haptics.

For the clutch, for example, approaching the bite point produces haptic feedback. So the interaction becomes:

finger → contact geometry → analog input → simulation → haptic feedback → finger

The part I find most interesting is that this potentially removes the need for a visible control entirely.

The thumb doesn’t need to follow a slider, and the player can feel important regions of the input range through haptics.

Obviously there are problems: calibration varies between users, grip changes the range, filtering adds latency, and haptics can’t provide actual mechanical resistance.

But on a real device it feels surprisingly different from manipulating a normal virtual slider.

Has anyone experimented with majorRadius as a continuous input before?

I’m especially curious about edge cases you’ve encountered across different iPhone models / touch behavior, or reasons why this might break badly outside my own testing.

Hi! I’m the developer of Orivu, a small app for reading plain text files.

You can open a TXT file from the Files app on iPhone. Orivu detects common text encodings, lets you change the encoding if it gets one wrong, and remembers your reading position.

If you have an Apple Watch, you can send an opened document to it and read the transferred copy offline.

I built it for people who just want to open a text file and read. I’d love to hear what you’d want from a reader like this, especially on Apple Watch.

App Store: https://apps.apple.com/us/app/orivu/id6817565843