Touch Heatmap Tracker: Kernel Density Event Tracking (2D)

Mobile analytics SDKs turn raw touch events into behavioral insight through touch heatmaps and scroll tracking. This 2D simulator streams synthetic tap events onto a flat phone-screen density field and accumulates them into a live kernel-density heatmap exactly the way tools like Firebase Analytics, Amplitude and session-recording SDKs aggregate real user taps. Tap rate controls event volume, kernel bandwidth σ controls how far each tap's Gaussian influence spreads across the grid, and a session decay half-life makes older taps fade — a rolling window rather than infinite memory. On top of the color map, isodensity contour lines (traced with marching squares) outline regions of equal density, and marginal density strips along the bottom and right edges show the row/column sums of the field — the exact horizontal and vertical tap-clustering profile. A realistic-vs-uniform toggle contrasts taps clustered around real UI zones against a structureless null model, while live readouts track total events, peak cell density, screen coverage and the marginal peak location.