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
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:
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 ( $dest_image );
? }
} // End of class definition
?>
使用方法：
1、首先引用該php文件（不要告訴我不會)
2、調(diào)用代碼
?$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，就會幫你生成一個 差不多大小的文件，一般來說除非你的圖片很有個性，譬如很長，否則縮略圖生成的還是很體貼的。
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
How to get the current session ID in PHP?
Jul 13, 2025 am 03:02 AM
The method to get the current session ID in PHP is to use the session_id() function, but you must call session_start() to successfully obtain it. 1. Call session_start() to start the session; 2. Use session_id() to read the session ID and output a string similar to abc123def456ghi789; 3. If the return is empty, check whether session_start() is missing, whether the user accesses for the first time, or whether the session is destroyed; 4. The session ID can be used for logging, security verification and cross-request communication, but security needs to be paid attention to. Make sure that the session is correctly enabled and the ID can be obtained successfully.
PHP get substring from a string
Jul 13, 2025 am 02:59 AM
To extract substrings from PHP strings, you can use the substr() function, which is syntax substr(string$string,int$start,?int$length=null), and if the length is not specified, it will be intercepted to the end; when processing multi-byte characters such as Chinese, you should use the mb_substr() function to avoid garbled code; if you need to intercept the string according to a specific separator, you can use exploit() or combine strpos() and substr() to implement it, such as extracting file name extensions or domain names.
How do you perform unit testing for php code?
Jul 13, 2025 am 02:54 AM
UnittestinginPHPinvolvesverifyingindividualcodeunitslikefunctionsormethodstocatchbugsearlyandensurereliablerefactoring.1)SetupPHPUnitviaComposer,createatestdirectory,andconfigureautoloadandphpunit.xml.2)Writetestcasesfollowingthearrange-act-assertpat
How to split a string into an array in PHP
Jul 13, 2025 am 02:59 AM
In PHP, the most common method is to split the string into an array using the exploit() function. This function divides the string into multiple parts through the specified delimiter and returns an array. The syntax is exploit(separator, string, limit), where separator is the separator, string is the original string, and limit is an optional parameter to control the maximum number of segments. For example $str="apple,banana,orange";$arr=explode(",",$str); The result is ["apple","bana
JavaScript Data Types: Primitive vs Reference
Jul 13, 2025 am 02:43 AM
JavaScript data types are divided into primitive types and reference types. Primitive types include string, number, boolean, null, undefined, and symbol. The values are immutable and copies are copied when assigning values, so they do not affect each other; reference types such as objects, arrays and functions store memory addresses, and variables pointing to the same object will affect each other. Typeof and instanceof can be used to determine types, but pay attention to the historical issues of typeofnull. Understanding these two types of differences can help write more stable and reliable code.
Using std::chrono in C
Jul 15, 2025 am 01:30 AM
std::chrono is used in C to process time, including obtaining the current time, measuring execution time, operation time point and duration, and formatting analysis time. 1. Use std::chrono::system_clock::now() to obtain the current time, which can be converted into a readable string, but the system clock may not be monotonous; 2. Use std::chrono::steady_clock to measure the execution time to ensure monotony, and convert it into milliseconds, seconds and other units through duration_cast; 3. Time point (time_point) and duration (duration) can be interoperable, but attention should be paid to unit compatibility and clock epoch (epoch)
How does PHP handle Environment Variables?
Jul 14, 2025 am 03:01 AM
ToaccessenvironmentvariablesinPHP,usegetenv()orthe$_ENVsuperglobal.1.getenv('VAR_NAME')retrievesaspecificvariable.2.$_ENV['VAR_NAME']accessesvariablesifvariables_orderinphp.iniincludes"E".SetvariablesviaCLIwithVAR=valuephpscript.php,inApach
How to pass a session variable to another page in PHP?
Jul 13, 2025 am 02:39 AM
In PHP, to pass a session variable to another page, the key is to start the session correctly and use the same $_SESSION key name. 1. Before using session variables for each page, it must be called session_start() and placed in the front of the script; 2. Set session variables such as $_SESSION['username']='JohnDoe' on the first page; 3. After calling session_start() on another page, access the variables through the same key name; 4. Make sure that session_start() is called on each page, avoid outputting content in advance, and check that the session storage path on the server is writable; 5. Use ses
