Pop\Image\Gd::convert PHP Метод

    public function convert($type)
    {
        $type = strtolower($type);
        // Check if the requested image type is supported.
        if (!array_key_exists($type, $this->allowed)) {
            throw new Exception('Error: That image type is not supported. Only GIF, JPG and PNG image types are supported.');
            // Check if the image is already the requested image type.
        } else {
            if (strtolower($this->ext) == $type) {
                throw new Exception('Error: This image file is already a ' . strtoupper($type) . ' image file.');
            }
        }
        // Else, save the image as the new type.
        // Open a new image, maintaining the GIF image's palette and
        // transparency where applicable.
        if ($this->mime == 'image/gif') {
            $this->createResource();
            imageinterlace($this->resource, 0);
            // Change the type of the image object to the new,
            // requested image type.
            $this->ext = $type;
            $this->mime = $this->allowed[$this->ext];
            // Redefine the image object properties with the new values.
            $this->fullpath = $this->dir . $this->filename . '.' . $this->ext;
            $this->basename = basename($this->fullpath);
            // Else, open a new true color image.
        } else {
            if ($type == 'gif') {
                $this->createResource();
                // Change the type of the image object to the new,
                // requested image type.
                $this->ext = $type;
                $this->mime = $this->allowed[$this->ext];
                // Redefine the image object properties with the new values.
                $this->fullpath = $this->dir . $this->filename . '.' . $this->ext;
                $this->basename = basename($this->fullpath);
            } else {
                $new = imagecreatetruecolor($this->width, $this->height);
                // Create a new, blank image file and copy the image over.
                $this->createResource();
                // Change the type of the image object to the new,
                // requested image type.
                $this->ext = $type;
                $this->mime = $this->allowed[$this->ext];
                // Redefine the image object properties with the new values.
                $this->fullpath = $this->dir . $this->filename . '.' . $this->ext;
                $this->basename = basename($this->fullpath);
                // Create and save the image in it's new, proper format.
                imagecopyresampled($new, $this->resource, 0, 0, 0, 0, $this->width, $this->height, $this->width, $this->height);
            }
        }
        return $this;
    }

 public function testConvertExceptionDupeType()
 {
     $this->setExpectedException('Pop\\Image\\Exception');
     $i = new Gd(__DIR__ . '/../tmp/test.gif');
     $i->convert('gif');
 }