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本文实例讲述了PHP生成图片缩略图类。分享给大家供大家参考，具体如下：
代码如下
classApp_image_helper {
protected$imgFileName;
protected$imgWidth;
protected$imgHeight;
protected$imgMime;
protected$imgResource;
static $imgMineList
=array(
'jpeg'=>'image/jpeg',
'gif'=>'image/gif',
'png'=>'image/png',
'wbmp'=>'image/wbmp',
);
/**
* 根据文件名，初始化图片，
* 计算出给定图片的宽、高、图片类型，并获取图片的资源保存到内存，便于下次使用
* App_image_helper constructor.
*
* @param $fileName
*/
publicfunction__construct($fileName) {
$this->imgFileName =$fileName;
list($this->imgWidth,$this->imgHeight,$this->imgMime) =$this->getImageInfo($this->imgFileName);
$this->imgResource =$this->getImageResource($this->imgFileName);
}
/**
* 根据图片路径获取相关宽、高、MIME类型信息
*
* @param $fileName
*
* @return array|null
*/
protectedfunctiongetImageInfo($fileName) {
$result= null;
if(is_file($fileName) ) {
$tmpImageInfo=getimagesize($fileName);
if($tmpImageInfo) {
$result=array($tmpImageInfo[0],$tmpImageInfo[1],$tmpImageInfo['mime']);
}
}
return$result;
}
/**
* 将图片文件转为资源类类型
*
* @param $fileName
*
* @return null|resource
*/
protectedfunctiongetImageResource($fileName) {
$image= null;
if(is_file($fileName) ) {
switch($this->imgMime) {
caseself::$imgMineList['jpeg']:
$image= imagecreatefromjpeg($fileName);
break;
caseself::$imgMineList['gif']:
$image= imagecreatefromgif($fileName);
break;
caseself::$imgMineList['png']:
$image= imagecreatefrompng($fileName);
break;
caseself::$imgMineList['wbmp']:
$image= imagecreatefromwbmp($fileName);
break;
default:
break;
}
}
return$image;
}
/**
* 可根据固定宽，等比缩放图片；或根据百分比，等比缩放图片
*
* @param int $width
* @param int $percent
*
* @return array|null
*/
protectedfunctiongetSizeByScale($width= 360,$percent= 1) {
$result= null;
if($this->imgWidth &&$this->imgHeight ) {
if($width) {
$result=array($width,intval($width*$this->imgHeight /$this->imgWidth));
}elseif($percent) {
$result=array(intval($this->imgWidth *$percent),intval($this->imgHeight *$percent));
}
}
return$result;
}
/**
* 外调
*
* @param int $percentOrWidth int整数表示图片缩放为固定宽度，0.0~0.99999表示缩放百分比
* @param null $fileName
* @param int $quality
* @param bool $reSample 重新采样图片，默认是
*
* @return bool
*/
publicfunctioncreateImage($percentOrWidth= 1,$fileName= null,$quality= 75,$reSample= true) {
$result= false;
$fileName? header('Content-Type: '.$this->imgMime) : false;
$size=$this->getSizeByScale(($percentOrWidth<= 1) ? null :$percentOrWidth,$percentOrWidth);
if($size) {
$thumb= imagecreatetruecolor($size[0],$size[1]);
if($reSample) {
imagecopyresampled($thumb,$this->imgResource, 0, 0, 0, 0,$size[0],$size[1],$this->imgWidth,$this->imgHeight);
}else{
imagecopyresized($thumb,$this->imgResource, 0, 0, 0, 0,$size[0],$size[1],$this->imgWidth,$this->imgHeight);
}
$result= imagejpeg($thumb,$fileName,$quality);
}
return$result;
}
}