Vertical spacing

The default behavior of TopLeaf is to include vertical space between paragraphs only when required. Space can be discarded in the following situations:

  • at the top or bottom of a page, or the top or bottom of a column in a multi-column layout;

  • where multiple spaces are present at a block boundary.

This last case occurs because the vertical space at a block boundary is resolved from the space below properties of the blocks that end there, and the space above properties of the blocks that begin at that same boundary. By default, where multiple vertical spaces are declared at a block boundary, all but the largest is discarded.

The following diagram illustrates this process:

The title mapping defines a space below of 12 points, while the p mapping has a space above of 6 points. The smaller space is discarded, so the actual space between the two paragraphs is 12 points.

There are times when retaining this space may be desirable. See Paragraph — Vertical Space retention for more information.