astra_replace_header_attr( array $attr, object $attachment, sting $size )

	function astra_replace_header_attr( $attr, $attachment, $size ) {

		if ( ! isset( $attachment ) ) {
			return $attr;
		}

		$custom_logo_id     = get_theme_mod( 'custom_logo' );
		$is_logo_attachment = ( $custom_logo_id == $attachment->ID ) ? true : false;

		if ( apply_filters( 'astra_is_logo_attachment', $is_logo_attachment, $attachment ) ) {

			if ( ! is_customize_preview() ) {
				$attach_data = wp_get_attachment_image_src( $attachment->ID, 'ast-logo-size' );

				if ( isset( $attach_data[0] ) ) {
					$attr['src'] = $attach_data[0];
				}
			}

			$file_type      = wp_check_filetype( $attr['src'] );
			$file_extension = $file_type['ext'];

			if ( 'svg' == $file_extension ) {
				$existing_classes = isset( $attr['class'] ) ? $attr['class'] : '';
				$attr['class']    = $existing_classes . ' astra-logo-svg';
			}
		}

		if ( apply_filters( 'astra_is_retina_logo_attachment', $is_logo_attachment, $attachment ) ) {

			$diff_retina_logo = astra_get_option( 'different-retina-logo' );

			if ( '1' == $diff_retina_logo ) {

				$retina_logo = astra_get_option( 'ast-header-retina-logo' );

				$attr['srcset'] = '';

				if ( apply_filters( 'astra_main_header_retina', true ) && '' !== $retina_logo ) {
					$cutom_logo     = wp_get_attachment_image_src( $custom_logo_id, 'full' );
					$cutom_logo_url = $cutom_logo[0];

					if ( astra_check_is_ie() ) {
						// Replace header logo url to retina logo url.
						$attr['src'] = $retina_logo;
					}

					$attr['srcset'] = $cutom_logo_url . ' 1x, ' . $retina_logo . ' 2x';
				}
			}
		}

		return apply_filters( 'astra_replace_header_attr', $attr );
	}