Returns the height of a string, in pixels.
function TextHeight(TextString: string): Word;
Takes the current font size and multiplication factor, and determines the height of TextString in pixels. This is useful for adjusting the spacing between lines, computing viewport heights, sizing a title to make it fit on a graph or in a box, and more.
For example, with the 8x8 bit-mapped font and a multiplication factor of 1 (set by SetTextStyle), the string Turbo is 8 pixels high.
It is important to use TextHeight to compute the height of strings, instead of doing the computation manually. In that way, no source code modifications have to be made when different fonts are selected.
Must be in graphics mode.