Resize.php

<?php

/*

  Original version:
  written by Jarrod Oberto
  taken from http://net.tutsplus.com/tutorials/php/image-resizing-made-easy-with-php/
  
  
  Modified From:
  Radoslav Stankov
  https://gist.github.com/RStankov/342704

  Example usage:
  include("classes/Resize.php");
  $resizer = new Resize('images/cars/large/input.jpg');
  $resizer->resizeImage(150, 100, 0);
  $resizer->saveImage('images/cars/large/output.jpg', 100);

 */

class Resize
{

    private $image;
    private $width;
    private $height;
    private $imageType;
    private $imageResized;

    function __construct($fileName)
    {
        $this->image  = $this->openImage($fileName);
        $this->width  = imagesx($this->image);
        $this->height = imagesy($this->image);
    }

    private function openImage($file)
    {
        if (!is_file($file))
        {
            throw new Exception("File {$file} doesn't exists");
        }

        //Get Information
        $imageInfo = getimagesize($file);

        if ($imageInfo)
        {
            switch ($imageInfo[2])
            {
                case IMAGETYPE_JPEG:
                    $this->imageType = IMAGETYPE_JPEG;
                    return imagecreatefromjpeg($file);

                case IMAGETYPE_GIF:
                    $this->imageType = IMAGETYPE_GIF;
                    return imagecreatefromgif($file);

                case IMAGETYPE_PNG:
                    $this->imageType = IMAGETYPE_PNG;
                    return imagecreatefrompng($file);
            }
        }
        else
        {
            throw new Exception("File {$file} doesn't appear to be a support format");
        }

        throw new Exception("Invalid image extension for {$file}. Acceptable image types are jpg,jpeg,gif,png");
    }

    public function resizeImage($newWidth, $newHeight, $option = 'auto')
    {
        list($width, $height) = $this->getDimensions($newWidth, $newHeight, $option);

        $this->imageResized = imagecreatetruecolor($width, $height);
        
        imagecopyresampled($this->imageResized, $this->image, 0, 0, 0, 0, $width, $height, $this->width, $this->height);

        if ($this->imageType == IMAGETYPE_PNG)
        {
            //Preserve Transparency
            imagesavealpha($this->imageResized, true);
            imagealphablending($this->imageResized, false);
        }


        if ($option == 'crop')
        {
            $this->crop($width, $height, $newWidth, $newHeight);
        }
    }

    private function getDimensions($width, $height, $option)
    {
        switch ($option)
        {
            case 'portrait':    return array($this->getSizeByFixedHeight($height), $height);
            case 'landscape':   return array($width, $this->getSizeByFixedWidth($width));
            case 'auto':        return $this->getSizeByAuto($width, $height);
            case 'crop':        return $this->getOptimalCrop($width, $height);
            case 'confine':     return $this->getSizeByConfinedSpace($width, $height);
            case 'exact':
            default: return array($width, $height);
        }
    }

    private function getSizeByFixedHeight($height)
    {
        return ($this->width / $this->height) * $height;
    }

    private function getSizeByFixedWidth($width)
    {
        return ($this->height / $this->width) * $width;
    }

    private function getSizeByAuto($width, $height)
    {
        if ($this->height < $this->width)
        {
            return array($width, $this->getSizeByFixedWidth($width));
        }

        if ($this->height > $this->width)
        {
            return array($this->getSizeByFixedHeight($height), $height);
        }

        if ($height < $width)
        {
            return array($width, $this->getSizeByFixedWidth($width));
        }

        if ($height > $width)
        {
            return array($this->getSizeByFixedHeight($height), $height);
        }

        return array($width, $height);
    }

    private function getSizeByConfinedSpace($maxwidth, $maxheight)
    {
        // Wriiten by: Andy Schuler 
        // http://code.tutsplus.com/tutorials/image-resizing-made-easy-with-php--net-10362#comment-693773779

        if ($newWidth >= $this->width && $newHeight >= $this->height)
        {
            //we're just going to return the original
            return array('optimalWidth' => $this->width, 'optimalHeight' => $this->height);
        }
        
        if($newWidth >= $this->width && $newHeight < $this->height )
        {
            //so we are height bound
            return array('optimalWidth' => $this->getSizeByFixedHeight($newHeight), 'optimalHeight' => $newHeight);
        }
        
        if($newHeight >= $this->height && $newWidth < $this->width )
        {
            //so we are width bound
            return array('optimalWidth' => $newWidth, 'optimalHeight' => $this->getSizeByFixedWidth($newWidth));
        }
        return $this->getSizeByAuto($newWidth, $newHeight);
    }

    private function getOptimalCrop($width, $height)
    {
        $ratio = min($this->height / $height, $this->width / $width);
        return array(
            $this->width / $ratio,
            $this->height / $ratio
        );
    }

    private function crop($optimalWidth, $optimalHeight, $width, $height)
    {
        $x = ( $optimalWidth / 2) - ( $width / 2 );
        $y = ( $optimalHeight / 2) - ( $height / 2 );

        $crop = $this->imageResized;

        $this->imageResized = imagecreatetruecolor($width, $height);
        
        if ($this->imageType == IMAGETYPE_PNG)
        {
            //Preserve Transparency
            imagesavealpha($this->imageResized, true);
            imagealphablending($this->imageResized, false);
        }
        
        imagecopyresampled($this->imageResized, $crop, 0, 0, $x, $y, $width, $height, $width, $height);
    }

    public function saveImage($savePath, $imageQuality = "100")
    {
        switch (pathinfo($savePath, PATHINFO_EXTENSION))
        {
            case 'jpg':
            case 'jpeg':
                if (imagetypes() & IMG_JPG)
                {
                    imagejpeg($this->imageResized, $savePath, $imageQuality);
                }
                break;

            case 'gif':
                if (imagetypes() & IMG_GIF)
                {
                    imagegif($this->imageResized, $savePath);
                }
                break;

            case 'png':
                if (imagetypes() & IMG_PNG)
                {
                    // Scale quality from 0-100 to 0-9
                    // Invert quality setting as 0 is best, not 9
                    $invertScaleQuality = 9 - round(($imageQuality / 100) * 9);
                    imagepng($this->imageResized, $savePath, $invertScaleQuality);
                }
                break;
        }

        imagedestroy($this->imageResized);
    }

}