define ( 'MAX_IMG_SIZE',100000 );

// Supported image types
define ( 'THUMB_JPEG','image/jpeg' );
define ( 'THUMB_PNG','image/png' );
define ( 'THUMB_GIF','image/gif' );

// Interlacing modes
define ( 'INTERLACE_OFF',0 );
define ( 'INTERLACE_ON',1 );

// Output modes
define ( 'STDOUT','' );

// Empty constants
define ( 'NO_logo','' );
define ( 'NO_LABEL','' );

// logo and label positioning
define ( 'POS_LEFT',0 );
define ( 'POS_RIGHT',1 );
define ( 'POS_CENTER',2 );
define ( 'POS_TOP',3 );
define ( 'POS_BOTTOM',4 );

// Error messages
define ( 'E_001','File %s do not exist' );
define ( 'E_002','Failed reading image data from %s' );
define ( 'E_003','Cannot create the copy of %s' );
define ( 'E_004','Cannot copy the logo image' );
define ( 'E_005','Cannot create final image' );

// ****************************************************************************
// CLASS DEFINITION
// ****************************************************************************

class ThumbnailImage
{

// ****************************************************************************
// PUBLIC PROPERTIES
// ****************************************************************************

var $src_file; // source image file
var $dest_file; // destination image file
var $dest_type; // destination image type

var $interlace; // destination image interlacing mode
var $jpeg_quality; // quality of resulting JPEG

var $max_width; // maximal thumbnail width
var $max_height; // maximal thumbnail height
var $fit_to_max; // enlarge small images?

var $logo; // array of logo parameters
var $label; // array of label parameters

// ****************************************************************************
// CLASS CONSTRUCTOR
// ****************************************************************************

/*
Description:
Defines default values for properties.
Prototype:
void ThumbImg ( string src_file = '' )
Parameters:
src_file - source image filename
*/
function ThumbnailImage ( $src_file = '' )
{

$this->src_file = $src_file;
$this->dest_file = STDOUT;
$this->dest_type = THUMB_JPEG;

$this->interlace = INTERLACE_OFF;
$this->jpeg_quality = -1;

$this->max_width = 100;
$this->max_height = 90;
$this->fit_to_max = FALSE;

$this->logo['file'] = NO_logo;
$this->logo['vert_pos'] = POS_TOP;
$this->logo['horz_pos'] = POS_LEFT;

$this->label['text'] = NO_LABEL;
$this->label['vert_pos'] = POS_BOTTOM;
$this->label['horz_pos'] = POS_RIGHT;
$this->label['font'] = '';
$this->label['size'] = 20;
$this->label['color'] = '#000000';
$this->label['angle'] = 0;

}

// ****************************************************************************
// PRIVATE METHODS
// ****************************************************************************

/*
Description:
Extracts decimal color components from hex color string.
Prototype:
array ParseColor ( string hex_color )
Parameters:
hex_color - color in '#rrggbb' format
Return:
Decimal values for red,green and blue color components.
*/
function ParseColor ( $hex_color )
{

if ( strpos ( $hex_color,'#' ) === 0 )
$hex_color = substr ( $hex_color,1 );

$r = hexdec ( substr ( $hex_color,2 ) );
$g = hexdec ( substr ( $hex_color,2,2 ) );
$b = hexdec ( substr ( $hex_color,4,2 ) );

return array ( $r,$g,$b );

}

/*
Description:
Retrives image data as a string.
Thanks to Luis Larrateguy for the idea of this function.
Prototype:
string GetImageStr ( string image_file )
Parameters:
image_file - filename of image
Return:
Image file contents string.
*/
function GetImageStr ( $image_file )
{

if ( function_exists ( 'file_get_contents' ) )
{
$str = @file_get_contents ( $image_file );
if ( ! $str )
{
$err = sprintf( E_002,$image_file );
trigger_error( $err,E_USER_ERROR );
}
return $str;
}

$f = fopen ( $image_file,'rb' );
if ( ! $f )
{
$err = sprintf( E_002,E_USER_ERROR );
}
$fsz = @filesize ( $image_file );
if ( ! $fsz )
$fsz = MAX_IMG_SIZE;
$str = fread ( $f,$fsz );
fclose ( $f );

return $str;

}

/*
Description:
Loads image from file.
Prototype:
resource LoadImage ( string image_file,int &image_width,int &image_height )
Parameters:
image_file - filename of image
image_width - width of loaded image
image_height - height of loaded image
Return:
Image identifier representing the image obtained from the given file.
*/
function LoadImage ( $image_file,&$image_width,&$image_height )
{

$image_width = 0;
$image_height = 0;

$image_data = $this->GetImageStr( $image_file );

$image = imagecreatefromstring ( $image_data );
if ( ! $image )
{
$err = sprintf( E_003,E_USER_ERROR );
}

$image_width = imagesx ( $image );
$image_height = imagesy ( $image );

return $image;

}

/*
Description:
Calculates thumbnail image sizes from source image width and height.
Prototype:
array GetThumbSize ( int src_width,int src_height )
Parameters:
src_width - width of source image
src_height - height of source image
Return:
An array with 2 elements. Index 0 contains the width of thumbnail image
and index 1 contains the height.
*/
function GetThumbSize ( $src_width,$src_height )
{

$max_width = $this->max_width;
$max_height = $this->max_height;

$x_ratio = $max_width / $src_width;
$y_ratio = $max_height / $src_height;

$is_small = ( $src_width <= $max_width && $src_height <= $max_height );

if ( ! $this->fit_to_max && $is_small )
{
$dest_width = $src_width;
$dest_height = $src_height;
}
elseif ( $x_ratio * $src_height < $max_height )
{
$dest_width = $max_width;
$dest_height = ceil ( $x_ratio * $src_height );
}
else
{
$dest_width = ceil ( $y_ratio * $src_width );
$dest_height = $max_height;
}

return array ( $dest_width,$dest_height );

}

/*
Description:
Adds logo image to thumbnail.
Prototype:
void Addlogo ( int thumb_width,int thumb_height,resource &thumb_img )
Parameters:
thumb_width - width of thumbnail image
thumb_height - height of thumbnail image
thumb_img - thumbnail image identifier
*/
function Addlogo ( $thumb_width,$thumb_height,&$thumb_img )
{

extract ( $this->logo );

$logo_image = $this->LoadImage ( $file,$logo_width,$logo_height );

if ( $vert_pos == POS_CENTER )
$y_pos = ceil ( $thumb_height / 2 - $logo_height / 2 );
elseif ($vert_pos == POS_BOTTOM)
$y_pos = $thumb_height - $logo_height;
else
$y_pos = 0;

if ( $horz_pos == POS_CENTER )
$x_pos = ceil ( $thumb_width / 2 - $logo_width / 2 );
elseif ( $horz_pos == POS_RIGHT )
$x_pos = $thumb_width - $logo_width;
else
$x_pos = 0;

if ( ! imagecopy ( $thumb_img,$logo_image,$x_pos,$y_pos,
$logo_width,$logo_height ) )
trigger_error( E_004,E_USER_ERROR );

}

/*
Description:
Adds label text to thumbnail.
Prototype:
void AddLabel ( int thumb_width,resource &thumb_img )
Parameters:
thumb_width - width of thumbnail image
thumb_height - height of thumbnail image
thumb_img - thumbnail image identifier
*/
function AddLabel ( $thumb_width,&$thumb_img )
{

extract ( $this->label );

list( $r,$b ) = $this->ParseColor ( $color );
$color_id = imagecolorallocate ( $thumb_img,$r,$b );

$text_Box = imagettfbBox ( $size,$angle,$font,$text );
$text_width = $text_Box [ 2 ] - $text_Box [ 0 ];
$text_height = abs ( $text_Box [ 1 ] - $text_Box [ 7 ] );

if ( $vert_pos == POS_TOP )
$y_pos = 5 + $text_height;
elseif ( $vert_pos == POS_CENTER )
$y_pos = ceil( $thumb_height / 2 - $text_height / 2 );
elseif ( $vert_pos == POS_BOTTOM )
$y_pos = $thumb_height - $text_height;

if ( $horz_pos == POS_LEFT )
$x_pos = 5;
elseif ( $horz_pos == POS_CENTER )
$x_pos = ceil( $thumb_width / 2 - $text_width / 2 );
elseif ( $horz_pos == POS_RIGHT )
$x_pos = $thumb_width - $text_width -5;

imagettftext ( $thumb_img,$size,
$color_id,$text );

}

/*
Description:
Output thumbnail image into the browser.
Prototype:
void OutputThumbImage ( resource dest_image )
Parameters:
dest_img - thumbnail image identifier
*/
function OutputThumbImage ( $dest_image )
{

imageinterlace ( $dest_image,$this->interlace );

header ( 'Content-type: ' . $this->dest_type );

if ( $this->dest_type == THUMB_JPEG )
imagejpeg ( $dest_image,'',$this->jpeg_quality );
elseif ( $this->dest_type == THUMB_GIF )
imagegif($dest_image);
elseif ( $this->dest_type == THUMB_PNG )
imagepng ( $dest_image );

}

/*
Description:
Save thumbnail image into the disc file.
Prototype:
void SaveThumbImage ( string image_file,resource dest_image )
Parameters:
image_file - destination file name
dest_img - thumbnail image identifier
*/
function SaveThumbImage ( $image_file,$dest_image )
{

imageinterlace ( $dest_image,$this->interlace );

if ( $this->dest_type == THUMB_JPEG )
imagejpeg ( $dest_image,$this->dest_file,$this->jpeg_quality );
elseif ( $this->dest_type == THUMB_GIF )
imagegif ( $dest_image,$this->dest_file );
elseif ( $this->dest_type == THUMB_PNG )
imagepng ( $dest_image,$this->dest_file );

}

// ****************************************************************************
// PUBLIC METHODS
// ****************************************************************************

/*
Description:
Output thumbnail image into the browser or disc file according to the
values of parameters.
Prototype:
void Output ( )
*/
function Output()
{

$src_image = $this->LoadImage($this->src_file,$src_width,$src_height);

$dest_size = $this->GetThumbSize($src_width,$src_height);

$dest_width=$dest_size[0];
$dest_height=$dest_size[1];

$dest_image=imagecreatetruecolor($dest_width,$dest_height);
if (!$dest_image)
trigger_error(E_005,E_USER_ERROR);

imagecopyresampled( $dest_image,$src_image,
$dest_width,$dest_height,$src_height );

if ($this->logo['file'] != NO_logo)
$this->Addlogo($dest_width,$dest_image);

if ($this->label['text'] != NO_LABEL)
$this->AddLabel($dest_width,$dest_image);

if ($this->dest_file == STDOUT)
$this->OutputThumbImage ( $dest_image );
else
$this->SaveThumbImage ( $this->dest_file,$dest_image );

imagedestroy ( $src_image );
imagedestroy ( $dest_image );

}

} // End of class definition

?>

$tis->max_width = 120;//自适应大小，但是最大宽度为120
$tis->max_height = 4000; //自适应大小，但是最大高度为4000
$tis->Output();