Source: terminal2.js

/*jslint plusplus: true, white: true, indent: 2, maxlen: 90 */
/**
 *  @author    Wolfgang Kowarschick
 *  @copyright 2013, Wolfgang Kowarschick
 *  <br/>
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted under the terms of the 
 *  Creative Commons License Attribution-NonCommercial-ShareAlike 3.0 Unported    
 *  (CC BY-NC-SA 3.0: http://creativecommons.org/licenses/by-nc-sa/3.0/). 
 */

(function($wk$, document)
{ "use strict"; 

  /**
   *  @class
   *  @name $wk$.Terminal2
   *  @param {String} p_terminal_id 
   *         The identifier of the canvas element where the lines are to be
   *         printed.
   *  @param {JSON} p_init 
   *         A JSON object that contains initial values for the terminal 
   *         (i.e. canvas):
   *         <code>width</code>, <code>height</code>, 
   *         <code>fontFamily</code>, <code>fontSize</code>, 
   *         <code>fontWeight</code>, <code>lineHeight</code>,
   *         <code>marginTop</code>, <code>marginLeft</code>.
   */
  var Terminal =
  function(p_terminal_id, p_init)
  { var l_key      = null,
        l_terminal = document.getElementById(p_terminal_id);
    
    // Default values
    this.width        = 600;
    this.height       = 600;
    this.fontFamily   = "'Times New Roman', Times, serif";
    this.fontSize     =  20;
    this.fontWeight   = "bold";
    this.lineHeight   =  25;
    this.marginTop    =   0;
    this.marginLeft   =  10;

    // Override defaults if wished
    /*jslint forin: true*/
    for (l_key in p_init)
    { this[l_key] = p_init[l_key]; }

    // All lines of text to be printed onto the canvas.
    this.v_lines = [];
    
    // The number of lines fitting on the canvas.
    this.v_canvas_length =
      Math.floor((this.height-this.marginTop-this.marginBottom)/this.lineHeight);
  
    l_terminal.width  = this.width;
    l_terminal.height = this.height;
    this.v_terminal   = l_terminal;
    this.v_context    = l_terminal.getContext("2d");    
  };
  
  Terminal.prototype =
  { /**
     *  Prints a line on the terminal.
     *  @method
     *  @name   $wk$.Terminal2#println
     *  @param  {String[]} arguments The strings to be printed.
     */
    println:
      function()
      { var i, n,
            l_text = "",
            l_sep  = "";
      
        for (i = 0, n = arguments.length; i < n; i++)
        { l_text += l_sep + arguments[i];
          l_sep = ", "; 
        }

        this.v_lines.push(l_text);
        if (this.v_lines.length > this.v_max_line_numbers)
        { this.v_lines.shift(); }

        this.v_context
            .clearRect(0, 0, this.v_terminal.width, this.v_terminal.height); 
        this.v_context.font 
          =   this.fontWeight + " " 
            + this.fontSize + "px" + " " 
            + this.fontFSamily;
        
        for (i = 0, n = this.v_lines.length; i < n; i++)
        { this.v_context.fillText(this.v_lines[i], 
                                  this.marginLeft, 
                                  this.marginTop+(i+1)*this.lineHeight
                                 ); 
        }
      }
  };
  
  $wk$.Terminal2 = Terminal;
  
}(this.$wk$, this.document));