Imagine an ordinary left-right slider (line with a grab) which runs from say -100 to 100. The position is the value ... it's a slider.


I've sometimes seen rather: a horizontal area the same shape as a slider. It's marked with chevrons pointing to the right on the right and left on the left.

You put your finger on it (actually anywhere) and move your finger left or right.

If you move left, it decreases the value; if you move right it increases the value.

(Perhaps velocity sensitive.)

So indeed, a track pad really, rather than a slider. (Your movement cues a delta, you're not selecting a value along the length.)

a - Is this just something I've seen in my mind because I'm mentally unbalanced, or does this exist?

b - what's it called?

c - think of an app that does this?

Here's a scratch version I did of what's in my head ...

enter image description here

Or put it this way ...

Imagine your phone app has an area at the bottom of the screen, where you can nudge your finger left or right (ie, as if dragging), and that will affect some value. (Imagine it, say, tweaking one joint of a 3D model joint on screen, perhaps.) How would you "indicate" that area; that the strip is a (let's say) sort of "touch strip" ("mouse-like value adjuster strip") .... ???

  • 2
    It exists, not sure what it is called, but you see this in many game-related apps for controlling movement (an alternative to a virtual joystick). It is probably used in more standard apps as well, but it would seem to be an overkill for a simple interaction, probably because the spinner control is out of fashion now.
    – Michael Lai
    May 19, 2016 at 0:14
  • Do you mean like this? js-tutorial.com/trackpad-scroll-emulator-1144 That tool mentioned Mac OS X Lion and rdo as apps that do similar things.
    – Tim Grant
    May 20, 2016 at 2:05

1 Answer 1


There's no chevron, but the behavior you are describing exist in Snapseed (photo editor for Android)

If you drag up/down, you will see the parameters you can affect. If you are dragging left/right, you can change the value of the previously selected parameter

up/down action

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