WP_Image_Editor::get_output_format( string $filename = null, string $mime_type = null ): array

344	protected function get_output_format( $filename = null, $mime_type = null ) {345		$new_ext = null;346 347		// By default, assume specified type takes priority.348		if ( $mime_type ) {349			$new_ext = $this->get_extension( $mime_type );350		}351 352		if ( $filename ) {353			$file_ext  = strtolower( pathinfo( $filename, PATHINFO_EXTENSION ) );354			$file_mime = $this->get_mime_type( $file_ext );355		} else {356			// If no file specified, grab editor's current extension and mime-type.357			$file_ext  = strtolower( pathinfo( $this->file, PATHINFO_EXTENSION ) );358			$file_mime = $this->mime_type;359		}360 361		/*362		 * Check to see if specified mime-type is the same as type implied by363		 * file extension. If so, prefer extension from file.364		 */365		if ( ! $mime_type || ( $file_mime === $mime_type ) ) {366			$mime_type = $file_mime;367			$new_ext   = $file_ext;368		}369 370		$output_format = wp_get_image_editor_output_format( $filename, $mime_type );371 372		if ( isset( $output_format[ $mime_type ] )373			&& $this->supports_mime_type( $output_format[ $mime_type ] )374		) {375			$mime_type = $output_format[ $mime_type ];376			$new_ext   = $this->get_extension( $mime_type );377		}378 379		/*380		 * Double-check that the mime-type selected is supported by the editor.381		 * If not, choose a default instead.382		 */383		if ( ! $this->supports_mime_type( $mime_type ) ) {384			/**385			 * Filters default mime type prior to getting the file extension.386			 *387			 * @see wp_get_mime_types()388			 *389			 * @since 3.5.0390			 *391			 * @param string $mime_type Mime type string.392			 */393			$mime_type = apply_filters( 'image_editor_default_mime_type', $this->default_mime_type );394			$new_ext   = $this->get_extension( $mime_type );395		}396 397		/*398		 * Ensure both $filename and $new_ext are not empty.399		 * $this->get_extension() returns false on error which would effectively remove the extension400		 * from $filename. That shouldn't happen, files without extensions are not supported.401		 */402		if ( $filename && $new_ext ) {403			$dir = pathinfo( $filename, PATHINFO_DIRNAME );404			$ext = pathinfo( $filename, PATHINFO_EXTENSION );405 406			$filename = trailingslashit( $dir ) . wp_basename( $filename, ".$ext" ) . ".{$new_ext}";407		}408 409		if ( $mime_type && ( $mime_type !== $this->mime_type ) ) {410			// The image will be converted when saving. Set the quality for the new mime-type if not already set.411			if ( $mime_type !== $this->output_mime_type ) {412				$this->output_mime_type = $mime_type;413			}414			$this->set_quality();415		} elseif ( ! empty( $this->output_mime_type ) ) {416			// Reset output_mime_type and quality.417			$this->output_mime_type = null;418			$this->set_quality();419		}420 421		return array( $filename, $new_ext, $mime_type );422	}