classes/handlers/gd.php
public function verticalFlip( $region = null )
    {
        $resource = $this->getActiveResource();

        $w = imagesx( $resource );
        $h = imagesy( $resource );

        $newResource = imagecreatetruecolor( $w, $h );

        imagealphablending( $newResource, false );
        imagesavealpha( $newResource, true );

        $res = imagecopyresampled( $newResource, $resource,
            0, 0,
            0, $h,
            $w, $h,
            $w, - $h );

        if ( $res === false )
        {
            throw new ezcImageFilterFailedException( 'rotate', 'Rotation of image failed.' );
        }

        imagedestroy( $resource );
        $this->setActiveResource( $newResource );
    }
public function verticalFlip( $region = null )
    {
        $resource = $this->getActiveResource();

        $w = imagesx( $resource );
        $h = imagesy( $resource );

        $newResource = imagecreatetruecolor( $w, $h );

        imagealphablending( $newResource, false );
        imagesavealpha( $newResource, true );

        $res = imagecopyresampled( $newResource, $resource,
            0, 0,
            0, $h,
            $w, $h,
            $w, - $h );

        if ( $res === false )
        {
            throw new ezcImageFilterFailedException( 'rotate', 'Rotation of image failed.' );
        }

        imagedestroy( $resource );
        $this->setActiveResource( $newResource );
    }
/* (non-PHPdoc)
@see extension/ezie/autoloads/eziezc/interfaces/eZIEEzcConversions#verticalFlip($region)