I am currently developing a new layout. This must be typeset on a grid, and every line starts at a multiple of 13bp from the top of the text area. To help me check, I'd like to have rules every 13bp ...
In ConTeXt, I am using the setting grid=yes to make all of the text in a document use grid typesetting. ConTeXt seems to automatically adjust the height of this grid based on the size of the font ...