Drawing Algorithms

The @hfu.digital/boardkit-core drawing module provides algorithms for processing raw pointer input into smooth, optimized strokes.

Point Simplification

Reduces the number of points in a stroke while preserving its visual shape. Uses the Ramer-Douglas-Peucker algorithm.

import { simplifyPoints } from '@hfu.digital/boardkit-core';

const simplified = simplifyPoints(rawPoints, tolerance);

Higher tolerance values produce fewer points (more simplified), while lower values preserve more detail.

Pressure Mapping

Maps raw stylus pressure values to actual stroke width.

import { pressureToWidth } from '@hfu.digital/boardkit-core';

const width = pressureToWidth(pressure, baseWidth);

Pressure values range from 0.0 to 1.0. The function returns baseWidth * multiplier, where the multiplier is linearly interpolated between minMultiplier and maxMultiplier based on pressure.

Stroke Smoothing

Applies Catmull-Rom spline interpolation to smooth jagged strokes.

import { smoothPoints } from '@hfu.digital/boardkit-core';

const smoothed = smoothPoints(points, tension);

Pipeline

These algorithms are typically chained in the input pipeline:

Raw PointerEvents → Collect points
  → smoothPoints() (reduce jitter)
  → simplifyPoints() (reduce point count)
  → pressureToWidth() (apply pressure sensitivity)
  → Create StrokeElement