<?php
/**
 * Class to hold information about an image and to provide basic operations on images.
 * @link http://www.yiiframework.com/extension/simpleimage/
 * @author tzur
 *
 */
class SimpleImage {
    /**
     * The image.
     * @var resource
     */
    var $image;
    /**
     * The type of the image.
     * @see http://www.php.net/manual/en/image.constants.php
     * @var integer
     */
    var $image_type;
    /**
     * The image informations.
     * @see http://www.php.net/manual/en/function.getimagesize.php 
     * @var array
     */
    var $image_info;

    /**
     * Creates the SimpleImage instance and loads all necessary information.
     * @param string $filename
     * @link http://www.php.net/manual/en/function.getimagesize.php
     * @link http://www.php.net/manual/en/function.imagecreatefromjpeg.php
     * @link http://www.php.net/manual/en/function.imagecreatefromgif.php
     * @link http://www.php.net/manual/en/function.imagecreatefrompng.php
     * 
     */
    function __construct($filename) {
        $this->image_info = $image_info = getimagesize($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);
        }
    }

    /**
     * Saves the image.
     * @param string $filename
     * @param int $image_type
     * @param int $compression
     * @param int $permissions
     * @link http://www.php.net/manual/en/function.imagejpeg.php
     * @link http://www.php.net/manual/en/function.imagegif.php
     * @link http://www.php.net/manual/en/function.imagepng.php
     * @link http://www.php.net/manual/en/function.chmod.php
     */
    function save($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);
        }
    }
    
    /**
     * Outputs the image.
     * @param int $image_type
     * @link http://www.php.net/manual/en/function.imagejpeg.php 
     * @link http://www.php.net/manual/en/function.imagegif.php 
     * @link http://www.php.net/manual/en/function.imagepng.php 
     */
    function output($image_type = IMAGETYPE_JPEG) {
        if ($image_type == IMAGETYPE_JPEG) {
            imagejpeg($this->image);
        } elseif ($image_type == IMAGETYPE_GIF) {
            imagegif($this->image);
        } elseif ($image_type == IMAGETYPE_PNG) {
            imagepng($this->image);
        }
    }
    
    /**
     * Returns the width of the image.
     * @return int Return the width of the image or false on errors. 
     * @link http://www.php.net/manual/en/function.imagesx.php 
     */
    function getWidth() {
        return imagesx($this->image);
    }
    
    /**
     * Returns the height of the image.
     * @return int Return the height of the image or false on errors. 
     * @link http://www.php.net/manual/en/function.imagesy.php 
     */
    function getHeight() {
        return imagesy($this->image);
    }
    
    /**
     * Resizes the image to given height.
     * Keeps the ratio.
     * @param number $height
     */
    function resizeToHeight($height) {
        $ratio = $height / $this->getHeight();
        $width = $this->getWidth() * $ratio;
        $this->resize($width, $height);
    }
    
    /**
     * Resizes the image to given width.
     * Keeps the ratio.
     * @param number $width
     */
    function resizeToWidth($width) {
        $ratio = $width / $this->getWidth();
        $height = $this->getHeight() * $ratio;
        $this->resize($width, $height);
    }
    
    /**
     * Scales the image with given scale.
     * @param number $scale
     */
    function scale($scale) {
        $width = $this->getWidth() * $scale / 100;
        $height = $this->getHeight() * $scale / 100;
        $this->resize($width, $height);
    }
    
    /**
     * Resizes the image to given width and height.
     * @param number $width
     * @param number $height
     * @link http://www.php.net/manual/en/function.imagecopyresampled.php
     */
    function resize($width, $height) {
        $new_image = imagecreatetruecolor($width, $height);
        imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
        $this->image = $new_image;
    }
    
    function blend($width, $height) {
   		$this->resizeToWidth($width);
    	$new_image = imagecreatetruecolor($width, $height);
    	imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $width, $height);
    	imagealphablending($new_image,true);
    	imagefilledrectangle($new_image, 0, 0,  $width, $height, imagecolorallocatealpha($new_image, 255, 255, 255, 30));
    	$this->image = $new_image;
    	
    }
}
?>