PHP缩略图生成和图片水印制作的方法

/**

 * Image constructor.

 * @param string $imagePath 图片路径

 * @param string $markPath 水印图片路径

 * @param int $new_width 缩略图宽度

 * @param int $new_height 缩略图高度

 * @param int $quality JPG图片格输出质量

 */

publicfunction__construct(string$imagePath,

              string$markPath= null,

              int$new_width= null,

              int$new_height= null,

              int$quality= 75)

{

  $this->imgPath =$_SERVER['DOCUMENT_ROOT'] .$imagePath;

  $this->waterMarkPath =$markPath;

  $this->newWidth =$new_width?$new_width:$this->width;

  $this->newHeight =$new_height?$new_height:$this->height;

  $this->quality =$quality?$quality: 75;

 

  list($this->width,$this->height,$this->type) =getimagesize($this->imgPath);

  $this->img =$this->_loadImg($this->imgPath,$this->type);

 

 

  //生成缩略图

  $this->_thumb();

  //添加水印图片

  if(!empty($this->waterMarkPath))$this->_addWaterMark();

  //输出图片

  $this->_outputImg();

}

/**

 * 缩略图(按等比例,根据设置的宽度和高度进行裁剪)

 */

privatefunction_thumb()

{

 

  //如果原图本身小于缩略图，按原图长高

  if($this->newWidth >$this->width)$this->newWidth =$this->width;

  if($this->newHeight >$this->height)$this->newHeight =$this->height;

 

  //背景图长高

  $gd_width=$this->newWidth;

  $gd_height=$this->newHeight;

 

  //如果缩略图宽高，其中有一边等于原图的宽高，就直接裁剪

  if($gd_width==$this->width ||$gd_height==$this->height) {

    $this->newWidth =$this->width;

    $this->newHeight =$this->height;

  }else{

 

    //计算缩放比率

    $per= 1;

 

    if(($this->newHeight /$this->height) > ($this->newWidth /$this->width)) {

      $per=$this->newHeight /$this->height;

    }else{

      $per=$this->newWidth /$this->width;

    }

 

    if($per< 1) {

      $this->newWidth =$this->width *$per;

      $this->newHeight =$this->height *$per;

    }

  }

 

  $this->newImg =$this->_CreateImg($gd_width,$gd_height,$this->type);

  imagecopyresampled($this->newImg,$this->img, 0, 0, 0, 0,$this->newWidth,$this->newHeight,$this->width,$this->height);

}

/**

 * 添加水印

 */

privatefunction_addWaterMark()

{

  $ratio= 1 / 5;//水印缩放比率

 

  $Width= imagesx($this->newImg);

  $Height= imagesy($this->newImg);

 

  $n_width=$Width*$ratio;

  $n_height=$Width*$ratio;

 

  list($markWidth,$markHeight,$markType) =getimagesize($this->waterMarkPath);

 

  if($n_width>$markWidth)$n_width=$markWidth;

  if($n_height>$markHeight)$n_height=$markHeight;

 

  $Img=$this->_loadImg($this->waterMarkPath,$markType);

  $Img=$this->_thumb1($Img,$markWidth,$markHeight,$markType,$n_width,$n_height);

  $markWidth= imagesx($Img);

  $markHeight= imagesy($Img);

  imagecopyresampled($this->newImg,$Img,$Width-$markWidth- 10,$Height-$markHeight- 10, 0, 0,$markWidth,$markHeight,$markWidth,$markHeight);

  imagedestroy($Img);

}

/**

 * 缩略图(按等比例)

 * @param resource $img 图像流

 * @param int $width

 * @param int $height

 * @param int $type

 * @param int $new_width

 * @param int $new_height

 * @return resource

 */

privatefunction_thumb1($img,$width,$height,$type,$new_width,$new_height)

{

 

  if($width<$height) {

    $new_width= ($new_height/$height) *$width;

  }else{

    $new_height= ($new_width/$width) *$height;

  }

 

  $newImg=$this->_CreateImg($new_width,$new_height,$type);

  imagecopyresampled($newImg,$img, 0, 0, 0, 0,$new_width,$new_height,$width,$height);

  return$newImg;

}