<classSpec xmlns="http://www.tei-c.org/ns/1.0" rend="add" ident="att.facsimile" module="MEI.facsimile" type="atts">
<desc xml:lang="en">Attributes that associate a feature corresponding with all or part of an image.</desc>
<attList>
<attDef ident="facs" usage="opt">
<gloss xml:lang="en">facsimile</gloss>
<desc xml:lang="en">Points to one or more images, portions of an image, or surfaces which correspond to
the current element.</desc>
<constraintSpec ident="check_facsTarget" scheme="schematron">
<constraint>
<sch:rule context="@facs">
<sch:assert role="warning" test="not(normalize-space(.) eq '')">@facs attribute should
have content.</sch:assert>
<sch:assert role="warning" test="every $i in tokenize(., '\s+') satisfies substring($i,2)=//mei:*[local-name() eq
'surface' or local-name() eq 'zone']/@xml:id">Each value in @facs should correspond to the @xml:id attribute of a surface or zone
element.</sch:assert>
</sch:rule>
</constraint>
</constraintSpec>
</attDef>
</attList>
</classSpec>