使用 PHP 5.0创建图形的巧妙方法

 
<?php 
class GraphicsEnvironment 
{ 
  public $width; 
  public $height; 
  public $gdo; 
  public $colors = array(); 

  public function __construct( $width, $height ) 
  { 
    $this->width = $width; 
    $this->height = $height; 
    $this->gdo = imagecreatetruecolor( $width, $height ); 
    $this->addColor( "white", 255, 255, 255 ); 
    imagefilledrectangle( $this->gdo, 0, 0, 
      $width, $height, 
      $this->getColor( "white" ) ); 
  } 

  public function width() { return $this->width; } 

  public function height() { return $this->height; } 

  public function addColor( $name, $r, $g, $b ) 
  { 
    $this->colors[ $name ] = imagecolorallocate( 
      $this->gdo, 
      $r, $g, $b ); 
  } 

  public function getGraphicObject() 
  { 
    return $this->gdo; 
  } 

  public function getColor( $name ) 
  { 
    return $this->colors[ $name ]; 
  } 

  public function saveAsPng( $filename ) 
  { 
    imagepng( $this->gdo, $filename ); 
  } 
   
  public function tx( $x ) 
  { 
    return $x * $this->width; 
  } 
    
  public function ty( $y ) 
  { 
    return $y * $this->height; 
  } 
} 

abstract class GraphicsObject 
{ 
  abstract public function render( $ge ); 
  abstract public function z(); 
} 

function zsort( $a, $b ) 
{ 
  if ( $a->z() < $b->z() ) return -1; 
  if ( $a->z() > $b->z() ) return 1; 
  return 0; 
} 

class Group extends GraphicsObject 
{ 
  private $z; 
  protected $members = array(); 
  public function __construct( $z ) 
  { 
    $this->z = $z; 
  } 
  public function add( $member ) 
  { 
    $this->members []= $member; 
  } 
  public function render( $ge ) 
  { 
    usort( $this->members, "zsort" ); 
    foreach( $this->members as $gobj ) 
    { 
      $gobj->render( $ge ); 
    } 
  } 
  public function z() { return $this->z; } 
} 

abstract class BoxObject extends GraphicsObject 
{ 
  protected $color; 
  protected $sx; 
  protected $sy; 
  protected $ex; 
  protected $ey; 
  protected $z; 

  public function __construct( $z, $color, $sx, $sy, $ex, $ey ) 
  { 
    $this->z = $z; 
    $this->color = $color; 
    $this->sx = $sx; 
    $this->sy = $sy; 
    $this->ex = $ex; 
    $this->ey = $ey; 
  } 

  public function render( $ge ) 
  { 
    $rsx = $ge->tx( $this->sx ); 
    $rsy = $ge->ty( $this->sy ); 
    $rex = $ge->tx( $this->ex ); 
    $rey = $ge->ty( $this->ey ); 
    $this->draw( $rsx, $rsy, $rex, $rey, 
          $ge->getGraphicObject(), 
          $ge->getColor( $this->color ) ); 
  } 

  abstract public function draw( $sx, $sy, 
    $ex, $ey, $gobj, $color ); 

  public function z() { return $this->z; } 
} 

class Line extends BoxObject 
{ 
  public function draw( $sx, $sy, $ex, $ey, 
    $gobj, $color ) 
  { 
    imageline( $gobj, $sx, $sy, $ex, $ey, 
       $color ); 
  } 
} 

class Rectangle extends BoxObject 
{ 
  public function draw( $sx, $sy, $ex, $ey, 
    $gobj, $color ) 
  { 
    imagefilledrectangle( $gobj, $sx, $sy, 
      $ex, $ey, $color ); 
  } 
} 

class Oval extends BoxObject 
{ 
  public function draw( $sx, $sy, $ex, $ey, 
    $gobj, $color ) 
  { 
    $w = $ex - $sx; 
    $h = $ey - $sy; 
    imagefilledellipse( $gobj, 
      $sx + ( $w / 2 ), $sy + ( $h / 2 ), 
      $w, $h, $color ); 
  } 
} 
?> 

 
$g1 = new Group( 0 ); 
$g1->add( new Oval( 200, "red", 0.1, 0.1, 0.5, 0.5 ) );   
$g1->add( new Rectangle( 100, "black", 0.4, 0.4, 0.9, 0.9 ) );