How to correctly draw a rectangular background under the text?

Question

PHP

How to correctly draw a rectangular background under the text. It's not a problem to draw through imagefilledrectangle, but what about when the text is wrapped.
I transfer it this way:

if($box[2] > $width - $margin*2){
        $text_new .= "\n".$word.$box[2];
    } else {
        $text_new .= " ".$word;
    }

Like in this picture:

Answer 1

a string into an array, the array is padded in length with spaces