Feature suggestion: Return font size and copy text.

1. Although the font size is passed in using `px` units, could it also be returned as a numeric value? This would make it easier to determine the line height based on the font size.

2. I would like to implement a "select and copy" feature on canvas. This might require determining the width and coordinates of each character—is this supported?

The issue names no files or tests. Start by locating the text-measurement and layout entry points that accept font size in px, then inspect their current return values and whether character widths or coordinates are exposed. Done means the numeric font-size request and the feasibility of canvas selection and copying are addressed.

Written by the indexing model from the issue text.