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Home Backend Development PHP Tutorial PHP generates an adaptive size thumbnail class and shares its usage_PHP tutorial

PHP generates an adaptive size thumbnail class and shares its usage_PHP tutorial

Jul 13, 2016 am 10:30 AM
php

Copy the following code directly and create a new file called thumbnailimage.php. It is best not to use capital letters for the file name. Copy the following code into it:

Copy code The code is as follows:

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, 0, 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, $image_file );
????? trigger_error( $err, 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, $image_file );
????? trigger_error( $err, 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, 0, 0,
????? $logo_width, $logo_height ) )
????? trigger_error( E_004, E_USER_ERROR );

? }

? /*
??? Description:
????? Adds label text to thumbnail.
??? Prototype:
????? void AddLabel ( 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 AddLabel ( $thumb_width, $thumb_height, &$thumb_img )
? {

??? extract ( $this->label );

??? list( $r, $g, $b ) = $this->ParseColor ( $color );
??? $color_id = imagecolorallocate ( $thumb_img, $r, $g, $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, $angle, $x_pos, $y_pos,
????? $color_id, $font, $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, 0, 0, 0, 0,
????? $dest_width, $dest_height, $src_width, $src_height );

??? if ($this->logo['file'] != NO_LOGO)
????? $this->AddLogo($dest_width, $dest_height, $dest_image);

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

?>


使用方法:
1、首先引用該php文件(不要告訴我不會(huì))
2、調(diào)用代碼
復(fù)制代碼 代碼如下:

?$tis = new ThumbnailImage();
?????$tis->src_file? = "這里寫源文件的路徑"
?????$tis->dest_type = THUMB_JPEG;//生成圖片的類型是 jpg
????? $tis->dest_file = '這里寫目標(biāo)文件的路徑';

?????$tis->max_width = 120;//自適應(yīng)大小,但是最大寬度為120
?????$tis->max_height = 4000; //自適應(yīng)大小,但是最大高度為4000
?????$tis->Output();

代碼關(guān)鍵在于 max_width 和max_height,填多少,就會(huì)幫你生成一個(gè) 差不多大小的文件,一般來說除非你的圖片很有個(gè)性,譬如很長(zhǎng),否則縮略圖生成的還是很體貼的。

www.bkjia.comtruehttp://www.bkjia.com/PHPjc/765724.htmlTechArticle把下面的代碼直接復(fù)制,新建一個(gè)文件叫做 thumbnailimage.php ,文件名最好不要用大寫,把以下代碼復(fù)制進(jìn)去: 復(fù)制代碼 代碼如下: ?php define (...
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