PHP生成图片缩略图类示例

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; } }