Touchscreens are Fingerpaint

What this post added

This post analyzes how touchscreens fundamentally break traditional GUI design assumptions based on a pointer model and Fitts's Law. It discusses the implications for UI design, including the reduced applicability of Steering Law, the increased importance of obvious and large touch targets due to lack of tactile feedback and hover states, and the challenges posed by finger occlusion. It also touches on subtle changes in eye focus, the continued relevance of 'hot zones' for touch targets, the absence of virtual edges to stop physical fingers, and the impact of handedness, fatigue, and multi-touch gestures like pinch-to-zoom and swipe. The post argues that touch interfaces require a new interaction model, moving from 'Etch-A-Sketch' to 'fingerpaint', and necessitates designers to consider anthropometric variations and new interaction paradigms.