PHP生成图片缩略图类示例

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：

class App_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 $fileName
 */
 public function __construct($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 $fileName
 *
 * @return array|null
 */
 protected function getImageInfo($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 $fileName
 *
 * @return null|resource
 */
 protected function getImageResource($fileName) {
 $image = null;
 if ( is_file($fileName) ) {
 switch ($this->imgMime) {
 case self::$imgMineList['jpeg']:
 $image = imagecreatefromjpeg($fileName);
 break;
 case self::$imgMineList['gif']:
 $image = imagecreatefromgif($fileName);
 break;
 case self::$imgMineList['png']:
 $image = imagecreatefrompng($fileName);
 break;
 case self::$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 $percent
 *
 * @return array|null
 */
 protected function getSizeByScale($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 $reSample 重新采样图片，默认是
 *
 * @return bool
 */
 public function createImage($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;
 }
}

PS：这里再为大家推荐几款比较实用的图片处理工具供大家参考使用：

在线图片转换BASE64工具： http://tools.jb51.net/transcoding/img2base64

ICO图标在线生成工具： http://tools.jb51.net/aideddesign/ico_img

在线Email邮箱图标制作工具： http://tools.jb51.net/email/emaillogo

在线图片格式转换(jpg/bmp/gif/png)工具： http://tools.jb51.net/aideddesign/picext