nagi1 / hill-chart

// Some math magic of the function responsible for produce

// hill-like curve and, correctly position and drag

// points on the Y axis

export const hillFn = (point: number) =>

  50 * Math.sin((Math.PI / 50) * point - (1 / 2) * Math.PI) + 50;

// The inverse of the same magic to convert back values from

// chart back to the original before hillFn(). mainly used

// in dragging event and setting the setting new values.

export const hillFnInverse = (point: number) =>

  (25 * (2 * Math.asin((point - 50) / 50) + Math.PI)) / Math.PI;

// Calculate when the point is just near to the right side of the chart

export const textOutRange = (x: number) => x >= 80 && x <= 100;

export const calculateTextPositionForX = (size: number, x: number) => {

  const margin = size + 5;

  return textOutRange(x) ? -1 * margin : margin;

};

export const calculateTextMarginForY = () => 5;

export const uId = () => Math.random().toString(36).slice(-6);