<?php
class PracaZObrazkami {

   var $image;
   var $image_type;

   function Nacitaj($filename) {
      $image_info = getimagesize($filename);
      $this->image_type = $image_info[2];
      if( $this->image_type == IMAGETYPE_JPEG ) {
         $this->image = imagecreatefromjpeg($filename);
      } elseif( $this->image_type == IMAGETYPE_GIF ) {
         $this->image = imagecreatefromgif($filename);
      } elseif( $this->image_type == IMAGETYPE_PNG ) {
         $this->image = imagecreatefrompng($filename);
      }
   }
   function Uloz($filename, $image_type=IMAGETYPE_JPEG, $compression=75, $permissions=null) {
      if( $image_type == IMAGETYPE_JPEG ) {
         imagejpeg($this->image,$filename,$compression);
      } elseif( $image_type == IMAGETYPE_GIF ) {
         imagegif($this->image,$filename);
      } elseif( $image_type == IMAGETYPE_PNG ) {
         imagepng($this->image,$filename);
      }
      if( $permissions != null) {
         chmod($filename,$permissions);
      }
   }
   function ZistiWidth() {
      return imagesx($this->image);
   }
   function ZistiHeight() {
      return imagesy($this->image);
   }
   function ZmenVelkostHeight($height) {
      $ratio = $height / $this->ZistiHeight();
      $width = $this->ZistiWidth() * $ratio;
      $this->resize($width,$height);
   }
   function ZmenVelkostWidth($width) {
      $ratio = $width / $this->ZistiWidth();
      $height = $this->ZistiHeight() * $ratio;
      $this->ZmenitVelkost($width,$height);
   }
   function ZmenitVelkostPercentualne($scale) {
      $width = $this->ZistiWidth() * $scale/100;
      $height = $this->ZistiHeight() * $scale/100;
      $this->ZmenitVelkost($width,$height);
   }
   function ZmenitVelkost($width,$height) {
      $new_image = imagecreatetruecolor($width, $height);
      imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->ZistiWidth(), $this->ZistiHeight());
      $this->image = $new_image;
   }
}
?>