原型模式

$prototype = new \IMooc\Canvas();
$prototype->init();

$canvas1 = clone $prototype;
$canvas1->rect(3, 6, 4, 12);
$canvas1->draw();

<?php
namespace IMooc;

class Canvas
{
    public $data;

    function init($width = 20, $height = 10)
    {
        $data = array();
        for ($i = 0; $i < $height; $i++)
        {
            for ($j = 0; $j < $width; $j++)
            {
                $data[$i][$j] = ‘*‘;
            }
        }
        $this->data = $data;
    }

    function draw()
    {
        foreach ($this->data as $line)
        {
            foreach ($line as $char)
            {
                echo $char;
            }
            echo "<br/>\n";
        }
    }

    function rect($a1, $a2, $b1, $b2)
    {
        foreach ($this->data as $k1 => $line)
        {
            if ($k1 < $a1 or  $k1 > $a2) continue;
            foreach ($line as $k2 => $char)
            {
                if($k2 < $b1 or $k2 > $b2) continue;
                $this->data[$k1][$k2] = ‘&nbsp‘;
            }
        }
    }
}