PHP generate image thumbnails, PNG transparent support

Note: This feature relies on the GD2 graphics library

recently to use PHP to generate thumbnails, find a bit online, found this article: PHP Generate thumbnail image

After a trial, we found that there were several problems:

1. PNG images generated thumbnails are in JPG format

2. PNG images generated thumbnails without transparent (translucent) effect (filled with black background)

3, the code syntax is relatively old

So, on the basis of this version of the simple modification is optimized a bit.

PHP generated thumbnail class

<?PHP/** desc:resize Image (PNG, JPG, GIF) * Author: Ten years later Brother Lou (http://www.cnblogs.com/lurenjiashuo/) * date:2014. 11.13 * Base from:http://www.oschina.net/code/snippet_5189_2491*/    classResizeimage {//type of picture        Private $type; //Actual width        Private $width; //actual height        Private $height; //the width after the change        Private $resize _width; //the height after the change        Private $resize _height; //whether or not to cut the map        Private $cut; //Source Image        Private $srcimg; //Destination Image Address        Private $dstimg; //temporarily created images        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)); //Initializing an image            $this-initi_img (); //Destination Image Address            $this-Dst_img ($savePath); //--            $this->width = Imagesx ($this-im); $this->height = Imagesy ($this-im); //Creating Images            $this-newimg (); Imagedestroy ($this-im); }        Private functionnewimg () {//The proportions of the altered image            $resize _ratio= ($this->resize_width)/($this-resize_height); //ratio of actual images            $ratio= ($this->width)/($this-height); if($this-cut) {                //Crop Chart                $newimg= Imagecreatetruecolor ($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 PriorityImagecopyresampled ($newimg,$this->im, 0, 0, 0, 0,$this->resize_width,$this->resize_height, (($this->height) *$resize _ratio),$this-height); } Else {                    //Width FirstImagecopyresampled ($newimg,$this->im, 0, 0, 0, 0,$this->resize_width,$this->resize_height,$this->width, (($this->width)/$resize _ratio)); }            } Else {                //do not cut the map                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); }        }        //Initializing an image        Private functioniniti_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 Destination Address        Private functionDst_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 used, the constructor of the class is called directly, and the constructor is as follows:

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

Parameters

$imgPath: Original image Address

$width: Thumbnail width

$height: High thumbnail image

$isCut: Whether clipping, bool value

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

Example

<? PHP     include "resizeimage.php";     // jpg    $jpgResize New false, "img/test_320_240.jpg");     // PNG    $pngResize New false, "Img/test_320_240.png");? >

Effect

PHP generate image thumbnails, PNG transparent support