<?php
 
/**
 * This function resizes a given image into the target file with the given width and height
 *
 * @author Ryan Pallas
 * @copyright 2010, released under GPL
 *
 * @example usage
 *      $src = "/var/www/images/uploads/image.jpg";
 *      $targ = "/var/www/images/uploads/thumbs/image.jpg";
 *      if( imageResize($src,$targ,100,75) ) echo "Successfully resized thumbnail";
 * 
 * @param string $src Source input file to be resized
 * @param string $target Target output after resizing
 * @param int $newWidth Target width
 * @param int $newHeight Target height
 * @param bool $abs Whether newwidth/newheight are final or maximum measurements (Default: FALSE)
 *
 * @return bool
 */
function imageResize($src,$target,$newWidth,$newHeight,$abs=FALSE)
    {
    /**
     * @var array source image info
     */
    $imgInfo = getimagesize($src);
 
    /**
     * return false if not an image
     */
    if($imgInfo == FALSE) return FALSE;
 
    /**
     * @var int width
     * @var int height
     * @var constant img type
     */
    list($origWidth,$origHeight,$imgtype) = $imgInfo;
 
    /**
     * absolute dimensions or max dimensions
     */
    if( !$abs )
        {
        /**
         * determine new width & height based on aspect ratio
         */
        $ratio = (($origWidth / $origHeight) > ($newWidth / $newHeight)) ? $newWidth / $origWidth : $newHeight / $origHeight; 
        $newWidth = (int) ($origWidth * $ratio); // set width with ratio
        $newHeight = (int) ($origHeight * $ratio); // set height with ratio
 
        /**
         * if original dimensions smaller than new, do not resize
         */
        if( $origHeight <= $newHeight && $origWidth <= $newWidth)
            {
            $newHeight = $origHeight;
            $newWidth = $origWidth;
        }
 
        /**
         * @var int image offset for resampling
         */
        $xOffset = 0;
        $yOffset = 0;
    } else
        {
        /**
         * set original sampling area based on exact new dimensions
         */
        $ratio = (($origWidth / $origHeight) < ($newWidth / $newHeight)) ? $newWidth / $origWidth : $newHeight / $origHeight; 
        $finalHeight = (int) floor($newHeight / $ratio);
        $finalWidth = (int) floor($newWidth / $ratio);
 
        /**
         * @var int offset to center resampling area on original source
         */
        $yOffset = ($finalHeight == $origHeight) ? 0 : floor( ($origHeight-$finalHeight)/2 );
        $xOffset = ($finalWidth == $origWidth) ?  0 : floor( ($origWidth-$finalWidth)/2 );
 
        /**
         * @var int resampling area of original source
         */
        $origHeight = $finalHeight;
        $origWidth = $finalWidth;
    }
 
    /**
     * determine file type for correct functions
     */
    switch($imgtype)
        { 
        case IMAGETYPE_JPEG: 
            $create = "imagecreatefromjpeg"; 
            $move = "imagejpeg"; 
            break; 
        case IMAGETYPE_GIF: 
            $create = "imagecreatefromgif"; 
            $move = "imagegif"; 
            break; 
        case IMAGETYPE_PNG: 
            $create = "imagecreatefrompng"; 
            $move = "imagepng"; 
            break; 
        case IMAGETYPE_WBMP: 
            $create = "imagecreatefromwbmp"; 
            $move = "imagewbmp"; 
            break; 
        default: 
            return FALSE; 
    }
 
    /**
     * @var image create image from source
     */
    $base = $create($src);
 
    /**
     * @var image create image to new size
     */
    $temp = imagecreatetruecolor($newWidth,$newHeight);
 
    /**
     * copy resampled original and resize to new image
     */
    imagecopyresampled($temp,$base,0,0,$xOffset,$yOffset,$newWidth,$newHeight,$origWidth,$origHeight);
 
    /**
     * move new image to destination
     * return true on success, false on failure
     */
    if ( $move($temp,$target) )
        {
        return TRUE;
    } else
        {
        return FALSE;
    }
}