PHP that supports png transparent images to generate thumbnail class sharing_PHP tutorial

Sharing of the php generated thumbnail class that supports png transparent images

This article mainly introduces the sharing of the php generated thumbnail class that supports png transparent images. The code of this article is based on the GD2 graphics library , support the generation of thumbnails from png transparent images, friends in need can refer to

Note: This function depends on the GD2 graphics library

I recently wanted to use PHP to generate thumbnails. I searched online and found this article: PHP generates image thumbnails

After trying it out, I found the following problems:

1. The thumbnails generated from png images are in jpg format

2. The thumbnail generated from the png image has no transparent (semi-transparent) effect (filled with black background)

3. The code syntax is relatively old

Therefore, we simply modified and optimized it based on this version.

PHP generate thumbnail class

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/* * desc: Resize Image(png, jpg, gif) * author: Brother Lu ten years later * date: 2014.11.13 */ class ResizeImage { //Picture type private $type; //Actual width private $width; //Actual height private $height; //Changed width private $resize_width; //Changed height private $resize_height; //Whether to crop the image private $cut; //Source image private $srcimg; //Target image address private $dstimg; //Temporarily created image private $im; function __construct($imgPath, $width, $height, $isCut, $savePath) { $this->srcimg = $imgPath; $this->resize_width = $width; $this->resize_height = $height; $this->cut = $isCut; //Type of picture $this->type = strtolower(substr(strrchr($this->srcimg,"."),1)); //Initialize image $this->initi_img(); //Target image address $this -> dst_img($savePath); //-- $this->width = imagesx($this->im); $this->height = imagesy($this->im); //Generate image $this->newimg(); ImageDestroy ($this->im); } private function newimg() { //The proportion of the changed image $resize_ratio = ($this->resize_width)/($this->resize_height); //Proportion of actual image $ratio = ($this->width)/($this->height); if($this->cut) { //Crop image $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height); if($this->type=="png") { imagefill($newimg, 0, 0, imagecolorallocatealpha($newimg, 0, 0, 0, 127)); } if($ratio>=$resize_ratio) { //High priority imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio) , $this->height); } else { //Width priority imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this-> ;width)/$resize_ratio)); } } else { //No cropping if($ratio>=$resize_ratio) { $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio); if($this->type=="png") { imagefill($newimg, 0, 0, imagecolorallocatealpha($newimg, 0, 0, 0, 127)); } imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $ this->height); } else { $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height); if($this->type=="png") { imagefill($newimg, 0, 0, imagecolorallocatealpha($newimg, 0, 0, 0, 127)); } imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $ this->height); } } if($this->type=="png") { imagesavealpha($newimg, true); imagepng ($newimg,$this->dstimg); } else { imagejpeg ($newimg,$this->dstimg); } } //Initialize image private function initi_img() { if($this->type=="jpg") { $this->im = imagecreatefromjpeg($this->srcimg); } if($this->type=="gif") { $this->im = imagecreatefromgif($this->srcimg); } if($this->type=="png") { $this->im = imagecreatefrompng($this->srcimg); } } //Image target address private function dst_img($dstpath) { $full_length = strlen($this->srcimg); $type_length = strlen($this->type); $name_length = $full_length-$type_length; $name = substr($this->srcimg,0,$name_length-1); $this->dstimg = $dstpath; } } ?>

Use

When using it, just call the constructor of the class directly. The constructor is as follows:

$resizeimage = new resizeimage($imgPath, $width, $height, $isCut, $savePath);

Parameters
$imgPath: original image address

$width: thumbnail width

$height: Thumbnail height

$isCut: Whether to cut, bool value

$savePath: thumbnail address (can be the same as the original image address)

Example

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include "ResizeImage.php";   //jpg $jpgResize = new ResizeImage("img/test_1920_1200.jpg", 320, 240, false, "img/test_320_240.jpg");   //png $pngResize = new ResizeImage("img/test_1024_746.png", 320, 240, false, "img/test_320_240.png");   ?>

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include "ResizeImage.php"; //jpg $jpgResize = new ResizeImage("img/test_1920_1200.jpg", 320, 240, false, "img/test_320_240.jpg");

//png $pngResize = new ResizeImage("img/test_1024_746.png", 320, 240, false, "img/test_320_240.png"); ?>

Effect http://www.bkjia.com/PHPjc/955276.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/955276.htmlTechArticleSupport the php generation of thumbnail class sharing for png transparent images. This article mainly introduces the php generation that supports png transparent images. Thumbnail sharing, the code in this article is based on the GD2 graphics library, which supports png transparency...