Detailed explanation of PHP full-featured non-deformation image cropping operation classes and usage

<?php

/**

* Author : smallchicken

* mode 1 : 强制裁剪，生成图片严格按照需要，不足放大，超过裁剪，图片始终铺满

* mode 2 : 和1类似，但不足的时候 不放大 会产生补白，可以用png消除。

* mode 3 : 只缩放，不裁剪，保留全部图片信息，会产生补白，

* mode 4 : 只缩放，不裁剪，保留全部图片信息，生成图片大小为最终缩放后的图片有效信息的实际大小，不产生补白

* 默认补白为白色，如果要使补白成透明像素，请使用SaveAlpha()方法代替SaveImage()方法

*

* 调用方法：

*

* $ic=new ImageCrop('old.jpg','afterCrop.jpg');

* $ic->Crop(120,80,2);

* $ic->SaveImage();

*    //$ic->SaveAlpha();将补白变成透明像素保存

* $ic->destory();

*

*

*/

class ImageCrop {

  var $sImage;

  var $dImage;

  var $src_file;

  var $dst_file;

  var $src_width;

  var $src_height;

  var $src_ext;

  var $src_type;

  function ImageCrop($src_file,$dst_file='') {

    $this->src_file=$src_file;

    $this->dst_file=$dst_file;

    $this->LoadImage();

  }

  function SetSrcFile($src_file) {

    $this->src_file=$src_file;

  }

  function SetDstFile($dst_file) {

    $this->dst_file=$dst_file;

  }

  function LoadImage() {

    list($this->src_width, $this->src_height, $this->src_type) = getimagesize($this->src_file);

    switch($this->src_type) {

      case IMAGETYPE_JPEG :

      $this->sImage=imagecreatefromjpeg($this->src_file);

      $this->ext='jpg';

      break;

      case IMAGETYPE_PNG :

      $this->sImage=imagecreatefrompng($this->src_file);

      $this->ext='png';

      break;

      case IMAGETYPE_GIF :

      $this->sImage=imagecreatefromgif($this->src_file);

      $this->ext='gif';

      break;

      default:

      exit();

    }

  }

  function SaveImage($fileName='') {

    $this->dst_file=$fileName ? $fileName : $this->dst_file;

    switch($this->src_type) {

      case IMAGETYPE_JPEG :

      imagejpeg($this->dImage,$this->dst_file,100);

      break;

      case IMAGETYPE_PNG :

      imagepng($this->dImage,$this->dst_file);

      break;

      case IMAGETYPE_GIF :

      imagegif($this->dImage,$this->dst_file);

      break;

      default:

      break;

    }

  }

  function OutImage() {

    switch($this->src_type) {

      case IMAGETYPE_JPEG :

      header('Content-type: image/jpeg');

      imagejpeg($this->dImage);

      break;

      case IMAGETYPE_PNG :

      header('Content-type: image/png');

      imagepng($this->dImage);

      break;

      case IMAGETYPE_GIF :

      header('Content-type: image/gif');

      imagegif($this->dImage);

      break;

      default:

      break;

    }

  }

  function SaveAlpha($fileName='') {

    $this->dst_file=$fileName ? $fileName . '.png' : $this->dst_file .'.png';

    imagesavealpha($this->dImage, true);

    imagepng($this->dImage,$this->dst_file);

  }

  function OutAlpha() {

    imagesavealpha($this->dImage, true);

    header('Content-type: image/png');

    imagepng($this->dImage);

  }

  function destory() {

    imagedestroy($this->sImage);

    imagedestroy($this->dImage);

  }

  function Crop($dst_width,$dst_height,$mode=1,$dst_file='') {

    if($dst_file) $this->dst_file=$dst_file;

    $this->dImage = imagecreatetruecolor($dst_width,$dst_height);

    $bg = imagecolorallocatealpha($this->dImage,255,255,255,127);

    imagefill($this->dImage, 0, 0, $bg);

    imagecolortransparent($this->dImage,$bg);

    $ratio_w=1.0 * $dst_width / $this->src_width;

    $ratio_h=1.0 * $dst_height / $this->src_height;

    $ratio=1.0;

    switch($mode) {

      case 1:    // always crop

      if( ($ratio_w < 1 && $ratio_h < 1) || ($ratio_w > 1 && $ratio_h > 1)) {

        $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

        $tmp_w = (int)($dst_width / $ratio);

        $tmp_h = (int)($dst_height / $ratio);

        $tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);

        $src_x = (int) (($this->src_width-$tmp_w)/2) ;

        $src_y = (int) (($this->src_height-$tmp_h)/2) ;

        imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);

        imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);

        imagedestroy($tmp_img);

      } else {

        $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

        $tmp_w = (int)($this->src_width * $ratio);

        $tmp_h = (int)($this->src_height * $ratio);

        $tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);

        imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

        $src_x = (int)($tmp_w - $dst_width) / 2 ;

        $src_y = (int)($tmp_h - $dst_height) / 2 ;

        imagecopy($this->dImage, $tmp_img, 0,0,$src_x,$src_y,$dst_width,$dst_height);

        imagedestroy($tmp_img);

      }

      break;

      case 2:    // only small

      if($ratio_w < 1 && $ratio_h < 1) {

        $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

        $tmp_w = (int)($dst_width / $ratio);

        $tmp_h = (int)($dst_height / $ratio);

        $tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);

        $src_x = (int) ($this->src_width-$tmp_w)/2 ;

        $src_y = (int) ($this->src_height-$tmp_h)/2 ;

        imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);

        imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);

        imagedestroy($tmp_img);

      } elseif($ratio_w > 1 && $ratio_h > 1) {

        $dst_x = (int) abs($dst_width - $this->src_width) / 2 ;

        $dst_y = (int) abs($dst_height -$this->src_height) / 2;

        imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,0,0,$this->src_width,$this->src_height);

      } else {

        $src_x=0;

        $dst_x=0;

        $src_y=0;

        $dst_y=0;

        if(($dst_width - $this->src_width) < 0) {

          $src_x = (int) ($this->src_width - $dst_width)/2;

          $dst_x =0;

        } else {

          $src_x =0;

          $dst_x = (int) ($dst_width - $this->src_width)/2;

        }

        if( ($dst_height -$this->src_height) < 0) {

          $src_y = (int) ($this->src_height - $dst_height)/2;

          $dst_y = 0;

        } else {

          $src_y = 0;

          $dst_y = (int) ($dst_height - $this->src_height)/2;

        }

        imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,$src_x,$src_y,$this->src_width,$this->src_height);

      }

      break;

      case 3:    // keep all image size and create need size

      if($ratio_w > 1 && $ratio_h > 1) {

        $dst_x = (int)(abs($dst_width - $this->src_width )/2) ;

        $dst_y = (int)(abs($dst_height- $this->src_height)/2) ;

        imagecopy($this->dImage, $this->sImage, $dst_x,$dst_y,0,0,$this->src_width,$this->src_height);

      } else {

        $ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;

        $tmp_w = (int)($this->src_width * $ratio);

        $tmp_h = (int)($this->src_height * $ratio);

        $tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);

        imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

        $dst_x = (int)(abs($tmp_w -$dst_width )/2) ;

        $dst_y = (int)(abs($tmp_h -$dst_height)/2) ;

        imagecopy($this->dImage, $tmp_img, $dst_x,$dst_y,0,0,$tmp_w,$tmp_h);

        imagedestroy($tmp_img);

      }

      break;

      case 4:    // keep all image but create actually size

      if($ratio_w > 1 && $ratio_h > 1) {

        $this->dImage = imagecreatetruecolor($this->src_width,$this->src_height);

        imagecopy($this->dImage, $this->sImage,0,0,0,0,$this->src_width,$this->src_height);

      } else {

        $ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;

        $tmp_w = (int)($this->src_width * $ratio);

        $tmp_h = (int)($this->src_height * $ratio);

        $this->dImage = imagecreatetruecolor($tmp_w ,$tmp_h);

        imagecopyresampled($this->dImage,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

      }

      break;

    }

  }

  // end Crop

}

?>