Fix #711 issue with multiple superscripts.
The previous code incorrectly implemented TeXbook rules. First off, the font metrics at issue should be those for the superscript/ subscript style, not the main style. Secondly, the metrics should be scaled by the font size. This changes some screenshotter tests (and they look more like TeX now).
Before Width: | Height: | Size: 8.7 KiB After Width: | Height: | Size: 8.7 KiB |
Before Width: | Height: | Size: 6.1 KiB After Width: | Height: | Size: 6.2 KiB |
Before Width: | Height: | Size: 11 KiB After Width: | Height: | Size: 11 KiB |
Before Width: | Height: | Size: 11 KiB After Width: | Height: | Size: 11 KiB |
Before Width: | Height: | Size: 14 KiB After Width: | Height: | Size: 14 KiB |
Before Width: | Height: | Size: 14 KiB After Width: | Height: | Size: 14 KiB |
Before Width: | Height: | Size: 17 KiB After Width: | Height: | Size: 17 KiB |
Before Width: | Height: | Size: 13 KiB After Width: | Height: | Size: 13 KiB |
Before Width: | Height: | Size: 13 KiB After Width: | Height: | Size: 14 KiB |
Before Width: | Height: | Size: 13 KiB After Width: | Height: | Size: 14 KiB |