Master items and stamping
Which master items appear on an IDML body page and where — the master page at the same position, MasterPageTransform, ShowMasterItems and stacking.
A body page shows the items of the master page in its own position, mapped onto it by MasterPageTransform, behind its own items.
In short A master item is never written into a body spread. It stays in the
MasterSpreads/ part, and every body page that applies the master shows it. Four things
decide what a page shows: AppliedMaster picks the master; the page's position in its
spread picks the master page (first from first, second from second); MasterPageTransform
maps that master page onto the body page; and the body spread's ShowMasterItems can hide
the whole master layer. Master items keep their master's stacking order and sit behind the
page's own items. Placing master items on a page this way is called stamping here.
Which master page feeds which body page
A master spread has pages of its own, placed in its spread space exactly as body pages are. A master item belongs to the master page its geometry falls on. A body page takes the items of the master page at its own position in its spread: on a facing spread, the left body page takes the master's left page and the right body page its right page. A one-page master feeds every body page that applies it.
So a master can hold a left-page folio at the outer left corner and a right-page folio at the outer right corner, and each body page gets only its own.
Two body pages apply a two-page master. Each receives the rule drawn on the master page in the same position, placed on its own page.
Neither rule is in the body spread's XML: both come from the master part.
MasterPageTransform
MasterPageTransform on a body <Page> maps the master page onto that page. It is six
numbers, like ItemTransform, and is almost always the identity: the master page's
top-left corner lands on the body page's top-left corner. A non-identity value shifts,
scales or rotates the master layer on that one page.
ShowMasterItems
ShowMasterItems="false" on the body <Spread> hides the master items on all its pages.
The flag belongs to the spread: InDesign ignores it on a <Page>. The same attribute on the
<MasterSpread> does not hide anything on the body pages that apply the master; the
two-page-spread example carries
ShowMasterItems="false" on its master and InDesign shows the master's rules on both body
pages.
Stacking
Master items keep their order from the master spread: the item written first is at the back. Groups on a master are shown with their members. As a whole they paint behind the body page's own items, so a background panel on the master never covers the page's text.
InDesign's own rule adds layers: a master item paints behind page items on the same layer, and still in layer order against items on other layers, so a master item on the top layer appears above page items on a lower layer.
Text on masters
A master text frame's story is laid out separately on every page that shows it. A folio holding a page-number marker therefore shows each body page's own number, and a running head holding a section marker or a running-head variable shows the value for that page. See text variables.
The MasterSpread element
| Attribute · MasterSpread | Values | Paged | paged.set |
|---|---|---|---|
| ItemTransform | number-list | read · written | |
| Name | text | read · written | name |
| PageCount | integer | written | |
| Self | id | read · written | |
| ShowMasterItems | true | read · written | |
| BaseName | enum / reference / text | written | |
| NamePrefix | enum | written | |
| OverriddenPageItemProps | — | not read | |
| PageColor in Properties | — | not read | |
| PrimaryTextFrame | — | not read |
Name is the composed display name (A-Master), made of NamePrefix (A) and BaseName
(Master). PrimaryTextFrame names a master text frame that receives the text when pages
are added automatically. OverriddenPageItemProps is editing bookkeeping and does not
change the result.
In Paged: the master page is chosen by position, items are routed by the centre of their bounds (a large item that covers half a master page or more also reaches a page it overlaps),
Supported · verified Supported · verifiedMasterPageTransformand the master spread's rotation are applied as full matrices, andShowMasterItemson the body spread is honoured. Master items paint in the master's document order with groups expanded to their members, behind all of the page's own items regardless of layer. Group transparency and drop shadows on master items are not applied, and a master based on another master contributes only its own items.
The next page covers what an override removes from this.
Frequently asked questions
Why don't master items appear in the body page's XML?
Because pages inherit them. They stay in the MasterSpreads/ part; only an overridden item
gets a copy in the body spread.
Which master page does a body page use? The one at the same position: the first page of a body spread takes the master's first page, the second takes the second. A single-page master feeds every page.
Does ShowMasterItems on the master spread hide its items?
No. The body spread's ShowMasterItems decides whether its pages show master items.
InDesign ignores the attribute on <Page> and the master's own value does not hide items on
body pages.
Do master items render behind the page's own content? Behind the page's items on the same layer. Across layers, the layer order still applies in InDesign.
Are grouped master items shown? Yes. A group on a master reaches the body pages like any other master item.
Master spreads & overrides
How an IDML body page combines its master's items with its own — master pages supply repeating items, and an OverrideList replaces or drops single items.
Override resolution
How an IDML body page's OverrideList names the master items it has taken over, so they are not shown from the master and the page's own copy stands in.