Style Inheritance

In order to compile the complete set of paragraph and character properties specified by any given style (as appropriate), a consumer must follow the rule of style inheritance to determine each property in that set.

Style inheritance states that styles of any given type may inherit from other styles of that type, and therefore a consumer must ‘build up’ the style information by following the inheritance tree. This inheritance is defined via the <basedOn> element, which specifies the @styleId of the parent style.

example:

To build up the resulting style, a consumer must trace the hierarchy (following each <basedOn> value) back to a style which has no <basedOn> element (is not based on another style). The resulting style is then constructed by following each level in the tree, applying the specified paragraph and/or character properties as appropriate. When properties conflict, they are overridden by each subsequent level (this includes turning OFF a property set at an earlier level). Properties which are not specified simply do not change those specified at earlier levels.

example:

<w:style w:type="character" w:styleId="Green">
  <w:name w:val="Green" /> 
  <w:basedOn w:val="Base" /> 
  <w:rPr>
    <w:color w:val="22B14C" /> 
  </w:rPr>
</w:style>
...
../Local Settings/Temp/styles.xml<w:style w:type="character" w:styleId="Base">
  <w:name w:val="Base" /> 
  <w:rPr>
    <w:rFonts w:ascii="Arial" w:hAnsi="Arial" /> 
    <w:b /> 
  </w:rPr>
</w:style>

The definition of the Green character style has a <basedOn> element which specifies the Base style. This means that any use of the Green style is defined as bold, green, Arial text. ]

Conversely, a producer should not output any property on a style which has already been set by a previous level of the style hierarchy, as well as those which match the document defaults. This means that if the document defaults or any previous level in a style’s hierarchy specify a property which is unchanged at this level, that property should not be part of the style definition in the resulting WordprocessingML.

[Example: If the document default font is Bauhaus 93 and the Heading 1 style also specifies the Bauhaus 93 font, then a producer should not output any <rFonts> element for the Heading 1 style definition, because that formatting is inherited from the document defaults. end example]