[NTG-context] replace characters with bounding boxes

Dear gang, Given a set body font and text, how does one replace all characters of that font in that text with the corresponding rectangular bounding boxes? Once an answer to the above is spelled out: How does one control the width of the lines which make up the bounding boxes? Thank you in advance. Best wishes Idris -- Idris Samawi Hamid, Professor Department of Philosophy Colorado State University Fort Collins, CO 80512