GdThumb::adaptiveResize PHP Method

    public function adaptiveResize($width, $height)
    {
        // make sure our arguments are valid
        if (!is_numeric($width) || $width == 0) {
            throw new InvalidArgumentException('$width must be numeric and greater than zero');
        }
        if (!is_numeric($height) || $height == 0) {
            throw new InvalidArgumentException('$height must be numeric and greater than zero');
        }
        // make sure we're not exceeding our image size if we're not supposed to
        if ($this->options['resizeUp'] === false) {
            $this->maxHeight = intval($height) > $this->currentDimensions['height'] ? $this->currentDimensions['height'] : $height;
            $this->maxWidth = intval($width) > $this->currentDimensions['width'] ? $this->currentDimensions['width'] : $width;
        } else {
            $this->maxHeight = intval($height);
            $this->maxWidth = intval($width);
        }
        $this->calcImageSizeStrict($this->currentDimensions['width'], $this->currentDimensions['height']);
        // resize the image to be close to our desired dimensions
        $this->resize($this->newDimensions['newWidth'], $this->newDimensions['newHeight']);
        // reset the max dimensions...
        if ($this->options['resizeUp'] === false) {
            $this->maxHeight = intval($height) > $this->currentDimensions['height'] ? $this->currentDimensions['height'] : $height;
            $this->maxWidth = intval($width) > $this->currentDimensions['width'] ? $this->currentDimensions['width'] : $width;
        } else {
            $this->maxHeight = intval($height);
            $this->maxWidth = intval($width);
        }
        // create the working image
        if (function_exists('imagecreatetruecolor')) {
            $this->workingImage = imagecreatetruecolor($this->maxWidth, $this->maxHeight);
        } else {
            $this->workingImage = imagecreate($this->maxWidth, $this->maxHeight);
        }
        $this->preserveAlpha();
        $cropWidth = $this->maxWidth;
        $cropHeight = $this->maxHeight;
        $cropX = 0;
        $cropY = 0;
        // now, figure out how to crop the rest of the image...
        if ($this->currentDimensions['width'] > $this->maxWidth) {
            $cropX = intval(($this->currentDimensions['width'] - $this->maxWidth) / 2);
        } elseif ($this->currentDimensions['height'] > $this->maxHeight) {
            $cropY = intval(($this->currentDimensions['height'] - $this->maxHeight) / 2);
        }
        imagecopyresampled($this->workingImage, $this->oldImage, 0, 0, $cropX, $cropY, $cropWidth, $cropHeight, $cropWidth, $cropHeight);
        // update all the variables and resources to be correct
        $this->oldImage = $this->workingImage;
        $this->currentDimensions['width'] = $this->maxWidth;
        $this->currentDimensions['height'] = $this->maxHeight;
        return $this;
    }

 /**
  * Resize and crop
  *
  * @param integer $width
  * @param integer $height
  * @return $this
  */
 public function crop($width, $height)
 {
     // GdThumb will not enforce the requested aspect ratio if the image is too
     // small, so we manually calculate what the size should be if the aspect
     // ratio is preserved.
     $options = $this->thumb->getOptions();
     if (empty($options['resizeUp'])) {
         $size = $this->thumb->getCurrentDimensions();
         $ratio = $width / $height;
         if ($size['width'] < $width) {
             $width = $size['width'];
             $height = $size['width'] / $ratio;
         }
         if ($size['height'] < $height) {
             $height = $size['height'];
             $width = $size['height'] * $ratio;
         }
     }
     // Do a normal adpative resize
     $this->thumb->adaptiveResize($width, $height);
     return $this;
 }