Use variable for interval

[rbdr/tomato-sauce] / lib / screens / mirrors.js

'use strict';

/**
 * Draws small moving gradient boxes and repeats them.
 *
 * @function MirrorsScreen
 * @implements IScreen
 */
module.exports = function (modulation, width, height, renderer) {

  const response = [];

  const scale = 2 + Math.round(Math.random() * 4);
  const scaledHeight = Math.floor(height / scale);
  const scaledWidth = Math.floor(width / scale);

  for (let i = 0; i < scaledHeight; ++i) {
    const row = [];
    for (let j = 0; j < scaledWidth; ++j) {
      const red = ((modulation + i) * 255 / height) % 255;
      const blue = ((modulation + j) * 255 / width) % 255;
      const green = ((modulation + i * j) * 255 / (width * height)) % 255;

      const cell = [renderer(red, blue, green), ' '];
      row.push(cell.join(''));
    }

    let rowText = '';
    for (let j = 0; j < scale; ++j) {
      rowText += row.reverse().join('');
    }

    for (let j = 1; j < scale; ++j) {
      response[j * i] = rowText;
      response[(height - 1 - (j * i))] = rowText;
    }
  }

  return response.join('\n');
};