php產生圖片縮圖，支援png透明

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註：此功能依賴GD2圖形庫

PHP產生縮圖類 

<?php    /*     * desc: Resize Image(png, jpg, gif)     * author: 十年後的盧哥哥(http://www.cnblogs.com/lurenjiashuo/)     * date: 2014.11.13     * base from: http://www.oschina.net/code/snippet_5189_2491     */    class ResizeImage { //圖片類型 private $type; //實際寬度 private $width; //實際高度 private $height; //改變後的寬度 private $resize_width; //改變後的高度 private $resize_height; //是否裁圖 private $cut; //源圖象 private $srcimg; //靶心圖表象地址 private $dstimg; //臨時建立的圖象 private $im; function __construct($imgPath, $width, $height, $isCut, $savePath) { $this->srcimg = $imgPath; $this->resize_width = $width; $this->resize_height = $height; $this->cut = $isCut; //圖片的類型 $this->type = strtolower(substr(strrchr($this->srcimg,"."),1)); //初始化圖象 $this->initi_img(); //靶心圖表象地址 $this -> dst_img($savePath); //-- $this->width = imagesx($this->im); $this->height = imagesy($this->im); //產生圖象 $this->newimg(); ImageDestroy ($this->im); } private function newimg() { //改變後的圖象的比例 $resize_ratio = ($this->resize_width)/($this->resize_height); //實際圖象的比例 $ratio = ($this->width)/($this->height); if($this->cut) { //裁圖 $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height); if($this->type=="png") { imagefill($newimg, 0, 0, imagecolorallocatealpha($newimg, 0, 0, 0, 127)); } if($ratio>=$resize_ratio) { //高度優先 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height); } else { //寬度優先 imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio)); } } else { //不裁圖 if($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,$this->dstimg); } } //初始化圖象 private function initi_img() { if($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); } } //圖象目標地址 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; } }?>

使用

使用時，直接調用類的建構函式即可，建構函式如下：

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

參數

$imgPath：原圖片地址

$width：縮圖寬

$height：縮圖高

$isCut：是否裁剪，bool值

$savePath：縮圖地址（可以跟原圖片地址相同）

樣本 

<?php    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");?>

效果

  

php產生圖片縮圖，支援png透明