Yii框架实现图片上传的方法详解

<?php
class Upload extends CActiveRecord {
  public $image;
  public static function model($className = __CLASS__) {
    return $className;
  }
  public function tableName() {
    return '{{resource}}';
  }
  public function rules() {
    return array(
      array('image', 'file', 'types'=>'jpg, gif, png')
    );
  }
}

<?php
class UploadController extends Controller {
  public function actionIndex() {
    $model=new Upload;
    if(isset($_POST['Upload'])) {
      $model->image=CUploadedFile::getInstance($model,'image');
      $ext = $model->image->getExtensionName();
      $fileName = uniqid() . '.' . $ext;
      $model->image->saveAs('assets/' . $fileName);
    }
    $this->renderPartial('index', array('model'=>$model));
  }
}

<meta charset="utf-8">
<?php echo CHtml::form(SITE_URL . 'admin/upload/index','post',array('enctype'=>'multipart/form-data')); ?>
<?php echo CHtml::activeFileField($model, 'image'); ?>
<?php echo CHtml::submitButton('提交');?>
<?php echo CHtml::endForm(); ?>

<?php
class Image extends CController {
  /**
   +----------------------------------------------------------
   * 取得图像信息
   *
   +----------------------------------------------------------
   * @static
   * @access public
   +----------------------------------------------------------
   * @param string $image 图像文件名
   +----------------------------------------------------------
   * @return mixed
   +----------------------------------------------------------
   */
  static function getImageInfo($img) {
    $imageInfo = getimagesize($img);
    if ($imageInfo !== false) {
      $imageType = strtolower(substr(image_type_to_extension($imageInfo[2]), 1));
      $imageSize = filesize($img);
      $info = array(
        "width" => $imageInfo[0],
        "height" => $imageInfo[1],
        "type" => $imageType,
        "size" => $imageSize,
        "mime" => $imageInfo['mime']
      );
      return $info;
    } else {
      return false;
    }
  }
  /**
   +----------------------------------------------------------
   * 生成缩略图
   +----------------------------------------------------------
   * @static
   * @access public
   +----------------------------------------------------------
   * @param string $image 原图
   * @param string $type 图像格式
   * @param string $thumbname 缩略图文件名
   * @param string $maxWidth 宽度
   * @param string $maxHeight 高度
   * @param string $position 缩略图保存目录
   * @param boolean $interlace 启用隔行扫描
   +----------------------------------------------------------
   * @return void
   +----------------------------------------------------------
   */
  static function thumb($image, $thumbname, $type='', $maxWidth=200, $maxHeight=50, $interlace=true) {
    // 获取原图信息
    $info = Image::getImageInfo($image);
    if ($info !== false) {
      $srcWidth = $info['width'];
      $srcHeight = $info['height'];
      $type = empty($type) ? $info['type'] : $type;
      $type = strtolower($type);
      $interlace = $interlace ? 1 : 0;
      unset($info);
      $scale = min($maxWidth / $srcWidth, $maxHeight / $srcHeight); // 计算缩放比例
      if ($scale >= 1) {
        // 超过原图大小不再缩略
        $width = $srcWidth;
        $height = $srcHeight;
      } else {
        // 缩略图尺寸
        $width = (int) ($srcWidth * $scale);
        $height = (int) ($srcHeight * $scale);
      }
      // 载入原图
      $createFun = 'ImageCreateFrom' . ($type == 'jpg' ? 'jpeg' : $type);
      if(!function_exists($createFun)) {
        return false;
      }
      $srcImg = $createFun($image);
      //创建缩略图
      if ($type != 'gif' && function_exists('imagecreatetruecolor'))
        $thumbImg = imagecreatetruecolor($width, $height);
      else
        $thumbImg = imagecreate($width, $height);
       //png和gif的透明处理 by luofei614
      if('png'==$type){
        imagealphablending($thumbImg, false);//取消默认的混色模式（为解决阴影为绿色的问题）
        imagesavealpha($thumbImg,true);//设定保存完整的 alpha 通道信息（为解决阴影为绿色的问题）
      }elseif('gif'==$type){
        $trnprt_indx = imagecolortransparent($srcImg);
         if ($trnprt_indx >= 0) {
            //its transparent
            $trnprt_color = imagecolorsforindex($srcImg , $trnprt_indx);
            $trnprt_indx = imagecolorallocate($thumbImg, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
            imagefill($thumbImg, 0, 0, $trnprt_indx);
            imagecolortransparent($thumbImg, $trnprt_indx);
       }
      }
      // 复制图片
      if (function_exists("ImageCopyResampled"))
        imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $width, $height, $srcWidth, $srcHeight);
      else
        imagecopyresized($thumbImg, $srcImg, 0, 0, 0, 0, $width, $height, $srcWidth, $srcHeight);
      // 对jpeg图形设置隔行扫描
      if ('jpg' == $type || 'jpeg' == $type)
        imageinterlace($thumbImg, $interlace);
      // 生成图片
      $imageFun = 'image' . ($type == 'jpg' ? 'jpeg' : $type);
      $imageFun($thumbImg, $thumbname);
      imagedestroy($thumbImg);
      imagedestroy($srcImg);
      return $thumbname;
    }
    return false;
  }
}
?>