getuserbarcode/lib/input_stream.js

An advanced barcode-scanner written in JavaScript

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

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;