apaou_all_fonts.php

<?php
/**
 * Filter the available fonts for each text preview field
 * List fonts in arrays using 'abel' => 'Abel' key / value pairs
 * Update the field IDs to match your own
 */
function demo_filter_all_fonts( $all_fonts, $available_fonts, $field ) {
	
	// Update the field IDs below to match your field IDs
	if( $field['field_id'] == 1209 ) {
		// Make an array of fonts for this field only
		$available_fonts = array(
			'abel'	=> 'Abel',
			'arial'	=> 'Arial'
		);
	} else if( $field['field_id'] == 1307 ) {
		// Make an array of fonts for this field only
		$available_fonts = array(
			'abel'		=> 'Abel',
			'courier'	=> 'Courier'
		);
	}
	
	$all_fonts = array_merge( array( 'default' => __( 'Default theme font', 'pr-advanced-previews-addons-ultimate' ) ), $available_fonts );
	
	return $all_fonts;
	
}
add_filter( 'apaou_all_fonts', 'demo_filter_all_fonts', 10, 3 );