Class Scale

code/draw_layout.js:82–104

// that the circles drawn around nodes’ center points don't get cut off.

class Scale {
  constructor(layout, width, height) {
    let xs = layout.map(node => node.x);
    let ys = layout.map(node => node.y);
    let minX = Math.min(...xs);
    let minY = Math.min(...ys);
    let maxX = Math.max(...xs);
    let maxY = Math.max(...ys);

    this.offsetX = minX; this.offsetY = minY;
    this.scaleX = (width - 2 * nodeSize) / (maxX - minX);
    this.scaleY = (height - 2 * nodeSize) / (maxY - minY);
  }

  // The `x` and `y` methods convert from graph coordinates into
  // canvas coordinates.
  x(x) {
    return this.scaleX * (x - this.offsetX) + nodeSize;
  }
  y(y) {
    return this.scaleY * (y - this.offsetY) + nodeSize;
  }
}