Create image thumbnails with PHP-PHP Tutorial-php.cn

Create image thumbnails with PHP

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Release： 2016-07-25 08:48:24

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/**
* Upload images to generate thumbnails
*
* Requires GD2 library support
*
* Parameters new thumbnails('original address of the image to be thumbnailed', 'width of thumbnail', 'height of thumbnail' are required during initialization ','(optional parameter) Thumbnail saving path');
* If the last parameter is not specified, the thumbnail will be saved in the small folder in the directory of the original image by default,
* If small does not exist folder, the small folder will be automatically created
*
* After initialization, you need to call the method produce to create thumbnails
* $thumbnails = new thumbnails(''....);
* $thumbnails->produce();
*
* You can get the relevant information of the original image, width, height, and image mime
*
* $thumbnails->getImageWidth(); //int image width
* $thumbnails->getImageHeight(); / / int Image height
* $thumbnails->getImageMime(); // string mime of the image
*
* $thumbnails->trueSize(); //array This is an array containing the width and sum of the image after scaling it down. Array of height values
* $size = array('width'=>'','height'=>'');
* Get the width and height of the image after scaling it
* $size['width ']//The width of the proportional thumbnail
* $size['height']//The height of the proportional thumbnail
*
*/
class thumbnails{
private $imgSrc; //Picture path
private $saveSrc; //Picture saving path, default is empty
private $ canvasWidth; //The width of the canvas
private $canvasHeight; //The height of the canvas
private $im; //Canvas resources
private $dm; //Resources returned by copying the image
/**
* Initialize the class and load related settings
*
* @param $imgSrc The path of the image that needs to be thumbnailed
* @param $canvasWidth The width of the thumbnail
* @param $canvasHeight The height of the thumbnail
*/
public function __construct($imgSrc,$canvasWidth,$canvasHeight,$saveSrc=null)
{
$this->imgSrc = $imgSrc;
$this->canvasWidth = $canvasWidth;
$this->canvasHeight = $ canvasHeight;
$this->saveSrc = $saveSrc;
}
/**
* Generate thumbnails
*/
public function produce()
{
$this->createCanvas();
$this->judgeImage ();
$this->copyImage();
$this->headerImage();
}
/**
* Get the information of the loaded image
*
* Contains the length, width, and image type
*
* @return array An array containing the image length, width, and mime
*/
private function getImageInfo()
{
return getimagesize($this- >imgSrc);
}
/**
* Get the length of the image
*
* @return int The width of the image
*/
public function getImageWidth()
{
$imageInfo = $this->getImageInfo();
return $imageInfo['0'];
}
/**
* Get the height of the image
*
* @return int The height of the image
*/
public function getImageHeight()
{
$imageInfo = $this->getImageInfo();
return $imageInfo['1'];
}
/**
* Get the type of image
*
* @return the mime value of the image
*/
public function getImageMime()
{
$imageInfo = $this->getImageInfo();
return $imageInfo['mime'];
}
/**
* Create canvas
*
* At the same time, put the created canvas resource into the attribute $this->im
*/
private function createCanvas ()
{
$size = $this->trueSize();
$this->im = imagecreatetruecolor($size['width'],$size['height']);
}
/* *
* Determine the mime value of the image and determine the function to use
*
* At the same time, put the created image resource into $this->dm
*/
private function judgeImage()
{
$mime = $this->getImageMime();
switch ($mime)
{
case 'image/png':$dm = imagecreatefrompng($this ->imgSrc);
break;
case 'image/gif':$dm = imagecreatefromgif($this->imgSrc);
break;
case 'image/jpg':$dm = imagecreatefromjpeg($this ->imgSrc);
break;
case 'image/jpeg':$dm = imagecreatefromgjpeg($this->imgSrc);
break;
}
$this->dm = $dm;
}
/**
* Determine the width and height of the image after being reduced
*
* This width and height are also used as the size of the canvas
*
* @return array The size of the image after being reduced in equal proportions
*/
public function trueSize()
{
$proportionW = $this->getImageWidth() / $this->canvasWidth;
$proportionH = $this->getImageHeight() / $this->canvasHeight;
if( ($this->getImageWidth() < $this->canvasWidth) && ($this->getImageHeight() < $this->canvasHeight) )
{
$trueSize = array('width'=>$this->getImageWidth(),'height'=>$this->getImageHeight());
}
elseif($proportionW >= $proportionH)
{
$trueSize = array('width'=>$this->canvasWidth,'height'=>$this->getImageHeight() / $proportionW);
}
else
{
$trueSize = array('width'=>$this->getImageWidth() / $proportionH,'height'=>$this->canvasHeight);
}
return $trueSize;
}
/**
* Copy the image to a new canvas
*
* The image will be scaled proportionally and will not be deformed
*/
private function copyImage()
{
$size = $this->trueSize();
imagecopyresized($this->im, $this->dm , 0 , 0 , 0 , 0 , $size['width'] , $size['height'] , $this->getImageWidth() , $this->getImageheight());
}
/**
* Export the image
*
* The name of the image is the same as the original image name by default
*
* The path is the small directory under the current directory of the large image
*
* If the small directory does not exist, it will be automatically created
*/
public function headerImage()
{
$position = strrpos($this->imgSrc,'/');
$imageName = substr($this->imgSrc,($position + 1));
if($this->saveSrc)
{
$imageFlode = $this->saveSrc.'/';
}
else
{
$imageFlode = substr($this->imgSrc,0,$position).'/small/';
}
if(!file_exists($imageFlode))
{
mkdir($imageFlode);
}
$saveSrc = $imageFlode.$imageName;
imagejpeg($this->im,$saveSrc);
}
}

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