Master spreads & overrides

A master spread is layout drawn once and shown on many pages; an override is how one page replaces or removes a single master item.

In short A long document repeats itself: the same running head, the same folio, the same background on page after page. In IDML that furniture lives once, on a master spread, and each body page that names the master in AppliedMaster shows the items of the master page at its position, behind its own items. An override is the exception: a body page lists master items in its OverrideList, and those items no longer come from the master; the page usually holds its own edited copy instead. This chapter takes the two halves in turn: what a master contributes, and what an override takes away.

Why a reader ends up here

A page shows too much, too little, or the wrong thing from its master. Predicting a body page means holding two facts together:

• What the master contributes. Master items are not written into the body spread. Which ones reach a page, and where, follows from AppliedMaster, the position of the page in its spread, MasterPageTransform and the spread's ShowMasterItems.
• What the page takes away. The page's OverrideList names master items it has taken over. Those are not shown from the master; the page's own copy, if it has one, is an ordinary page item.

The two pages

• Master items and stamping: which master page feeds which body page, MasterPageTransform, ShowMasterItems, and how master items stack under the page's own.
• Override resolution: OverrideList, replacing a master item, deleting one, and the override attributes a reader can ignore.

Stamping comes first because an override only makes sense once you know what it removes. The structure of MasterSpread itself is introduced on Master spreads in the layout-model chapter.

Frequently asked questions

What is a master spread in IDML? A spread in a MasterSpreads/ part whose items appear on every body page that names it in AppliedMaster. Its structure is the same as a body spread's.

What is the difference between stamping and override resolution? Stamping is what the master adds to a page: the items of the matching master page, placed on the body page behind its own items. Override resolution is what the page takes away: the master items named in its OverrideList are left out.

Why does a master item not appear in the body page's XML? Because it is inherited, not copied. Only an overridden item has a copy in the body spread, and that copy is then an ordinary page item of the body page.