# Touch, context, and fidgetability · Invisible details A finger is opaque. Rauno Freiberg points out in [Invisible Details of Interaction Design](https://rauno.me/craft/interaction-design) that on touch interfaces the finger sometimes obscures exactly what you are manipulating, which makes pixel-level precision hard. The common answer is **touch content visibility** (On touch interfaces, sometimes a finger might obfuscate what's happening on the screen which makes it hard to perform gestures at pixel-level precision. Commonly, the interface would then render a temporary representation of what's underneath the finger.): render a temporary representation of what is underneath. ### Proxies that leave when done On iOS, dragging the text caret brings up a magnifying loupe above the touch point, and when the finger moves down and no longer covers the caret, the loupe disappears. It exists only while needed. The keyboard does the same in miniature: pressing a key shows an enlarged copy, confirming the interface understood you. Mirroring is not always right. Sliders can be tiny and vanish under a thumb; there the useful detail is that the drag does not cancel when the thumb drifts off while still pressing. Video scrubbing is the case nothing rescues: seeking is mostly visual, and Rauno describes “an unintelligible level of discomfort” in handling an element you cannot see. ### Context as input Keyboard, mouse, touch, and voice are all **explicit inputs** (The keyboard, mouse, touch, voice are all explicit inputs.), a natural extension of ourselves when dialled in. But is the mother of all inputs not no input at all? **Implicit input** (When an interface makes use of context as input and can infer what you're trying to do without asking, it truly feels magical.) is when an interface uses context and infers what you want without asking. Apple Maps shows the active route when you look at the screen, without unlocking. Apple Wallet raises the brightness when you present a pass. Spotify adapts its interface while you drive. And some iOS apps blur their contents in the App Switcher: not a performance optimisation, as he first assumed, but deliberate concealment of sensitive data like medical records or a bank statement. Context can hide as well as reveal. Source The loupe, keyboard popups, sliders, and scrubbing are from Touch Content Visibility; Maps, Wallet, Spotify, and the blurred switcher are from Implicit Input, both in the second half of the essay. ### Finding your place, and fidgeting On macOS you find the pointer by shaking the mouse, which Rauno likes because it taps into the frustration people already feel when they lose it. His own reading problem: halfway down a page he wants to check something above, but scrolling up loses a precious scroll position. His prototype lets you double tap the scrollbar to place a **scroll landmark** (I made a tiny prototype where double tapping the scrollbar will place a landmark for the current scroll position.), wander, and double tap the landmark to return. It feels familiar because the scrollbar is already interactive on touch: long-pressing makes it draggable. His older minimap prototype, inspired by games with a bird’s eye view, came from the same instinct. The last detail has no practical purpose. “Wonderful interactions don’t have to be entirely practical.” Playing with an AirPods case, or twisting an Apple Pencil tip, is **fidgeting** (Behaviors like this are considered fidgeting. In other words, repetitive movements that apparently help release situational stress, or even enhance concentration.): repetitive movement that apparently releases situational stress or enhances concentration. He footnotes that no research supports the claim, but holds that fidgetability still feels like part of intentional design. The AirPods case is “uncannily satisfying to play with,” and assuming coincidence would be very generous. The Pencil tip is unscrewable for replacement, and twisting it gives a satisfying friction to play with while thinking. ### Two sides of the same coin Understanding why something feels right, he admits, does not come as intuitively as designing it to feel right, “but they are two sides of the same coin. There must be a reason.” It can be as simple as a spring curve or as innate as a metaphor, and analysing details beyond “it feels nice” nurtures taste and raises execution. Emil Kowalski, on multi-touch in [Building a drawer component](https://emilkowal.ski/ui/building-a-drawer-component), says why these details are called invisible: they align with inherent expectations, so when a feature works as you assume, you proceed without a second thought. His drawer ignores every touch after the first until release, so a second finger cannot make it jump. > Figure. TypeScriptIllustration Three habits. When a finger or pointer will cover the thing it manipulates, show a proxy and remove it when it is not needed. Ask what the interface already knows before asking the user; context can protect as well as help. And when you cannot explain why an interaction feels right, treat that as work left to do, the work [the Taste chapter](https://learn-ui.com/chapters/taste) is about.