quagga-graphite/lib/input_stream.js

An advanced barcode-scanner written in JavaScript

const GetPixels = require("get-pixels-graphite");

var InputStream = {};

InputStream.createImageStream = function () {
  var that = {};
  var _config = null;

  var width = 0,
    height = 0,
    frameIdx = 0,
    paused = true,
    loaded = false,
    frame = null,
    baseUrl,
    ended = false,
    size,
    calculatedWidth,
    calculatedHeight,
    _eventNames = ["canrecord", "ended"],
    _eventHandlers = {},
    _topRight = { x: 0, y: 0 },
    _canvasSize = { x: 0, y: 0 };

  function loadImages() {
    loaded = false;
    GetPixels(baseUrl, _config.mime, function (err, pixels) {
      if (err) {
        console.log(err);
        exit(1);
      }
      loaded = true;
      console.log(pixels.shape);
      frame = pixels;
      width = pixels.shape[0];
      height = pixels.shape[1];
      calculatedWidth = _config.size
        ? width / height > 1
          ? _config.size
          : Math.floor((width / height) * _config.size)
        : width;
      calculatedHeight = _config.size
        ? width / height > 1
          ? Math.floor((height / width) * _config.size)
          : _config.size
        : height;

      _canvasSize.x = calculatedWidth;
      _canvasSize.y = calculatedHeight;

      setTimeout(function () {
        publishEvent("canrecord", []);
      }, 0);
    });
  }

  function publishEvent(eventName, args) {
    var j,
      handlers = _eventHandlers[eventName];

    if (handlers && handlers.length > 0) {
      for (j = 0; j < handlers.length; j++) {
        handlers[j].apply(that, args);
      }
    }
  }

  that.trigger = publishEvent;

  that.getWidth = function () {
    return calculatedWidth;
  };

  that.getHeight = function () {
    return calculatedHeight;
  };

  that.setWidth = function (width) {
    calculatedWidth = width;
  };

  that.setHeight = function (height) {
    calculatedHeight = height;
  };

  that.getRealWidth = function () {
    return width;
  };

  that.getRealHeight = function () {
    return height;
  };

  that.setInputStream = function (stream) {
    _config = stream;
    baseUrl = _config.src;
    size = 1;
    loadImages();
  };

  that.ended = function () {
    return ended;
  };

  that.setAttribute = function () {};

  that.getConfig = function () {
    return _config;
  };

  that.pause = function () {
    paused = true;
  };

  that.play = function () {
    paused = false;
  };

  that.setCurrentTime = function (time) {
    frameIdx = time;
  };

  that.addEventListener = function (event, f) {
    if (_eventNames.indexOf(event) !== -1) {
      if (!_eventHandlers[event]) {
        _eventHandlers[event] = [];
      }
      _eventHandlers[event].push(f);
    }
  };

  that.setTopRight = function (topRight) {
    _topRight.x = topRight.x;
    _topRight.y = topRight.y;
  };

  that.getTopRight = function () {
    return _topRight;
  };

  that.setCanvasSize = function (size) {
    _canvasSize.x = size.x;
    _canvasSize.y = size.y;
  };

  that.getCanvasSize = function () {
    return _canvasSize;
  };

  that.getFrame = function () {
    if (!loaded) {
      return null;
    }
    return frame;
  };

  return that;
};

module.exports = InputStream;