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;
    }