<alternatives> Alternatives For Processing

Container element used to hold a group of processing alternatives, for example, a single <graphic> that ships in several formats (tif, gif, and jpeg) or in different resolutions. This element is a physical grouping to contain multiple logically equivalent (substitutable) versions of the same information object. Typically these are processing alternatives, and the reader is expected to see only one version of the object.

Usage/Remarks

<alternatives> is neither inherently block nor inherently inline in nature, because the block or inline quality is determined by context and usage. Typical examples for this element are a <graphic> that ships with a document in multiple versions (for example, as a .tif, a .jpeg, and an SVG file); or an <inline-formula> that is available as a .tif (<inline-graphic>), encoded in MathML and as a plain ASCII. These graphics may be loose inside a paragraph or enclosed in a structure such as a figure.
Accessibility
This element, by providing a container for alternative versions of a media or graphical object, enables providing a textual alternative to any media or graphical object as well as providing an enlarged version of the graphic for accessibility.
Attributes

Base Attributes

Models and Context
May be contained in
Description
Content Model
<!ELEMENT  alternatives %alternatives-model;                         >
Expanded Content Model

((object-id)*, (chem-struct | code | graphic | inline-graphic | inline-media | inline-supplementary-material | media | preformat | private-char | supplementary-material | table | textual-form | mml:math)+)

Tagged Samples
Alternatives to a table inside <table-wrap>
One tagged XML and two graphical alternatives
...
<table-wrap id="pbio-0020328-t003" position="float">
 <caption>
  <title>Systematic Inactivation of SpoIIID-Activated Genes</title>
 </caption>
 <alternatives>

  <graphic xlink:href="pbio.0020328.t003.tif">
   <object-id pub-id-type="doi" content-type="image">10.0020328/2007SS000314(2007)</object-id>
  </graphic>

  <graphic xlink:href="pbio.0020328.t003.gif">
   <object-id pub-id-type="doi" content-type="image">10.0020328a/2007SS000314(2007)</object-id>
  </graphic>

  <table frame="box" rules="all" cellpadding="5">
   <thead>
    <tr>
     <td>Strain</td>
     <td>Description</td>
     <td>Sporulation Efficiency (Percent)<sup>a</sup></td>
    </tr>
   </thead>
    <tbody>...</tbody>
  </table>

 </alternatives>
 <table-wrap-foot>
  <fn id="nt301">
   <p><sup>a</sup>&thinsp;Sporulation efficiency is defined as the
    number of heat-resistant spores ...</p>
  </fn>
 </table-wrap-foot>
</table-wrap>
...
Equation alternatives (MathML, graphical)
One tagged MathML and one graphical
...
<disp-formula id="pbio-0020328-e001">
 <alternatives>
  <mml:math display="block" xmlns:mml="http://www.w3.org/1998/Math/MathML">
   <mml:mrow>
    <mml:msub>
     <mml:mrow><mml:mtext>Strength</mml:mtext></mml:mrow>
     <mml:mi>i</mml:mi>
    </mml:msub>
    <mml:mo>=</mml:mo>
    <mml:mi>log</mml:mi>
    <mml:mo>&ApplyFunction;</mml:mo>
    <mml:mfrac>...</mml:mfrac>
    ...
   </mml:mrow>
  </mml:math>
  <graphic xlink:href="pbio.0020328.e001.gif">
   <object-id/>
  </graphic>
 </alternatives>
</disp-formula>
...
...
<disp-formula id="eq_002">
 <label>(2)</label>
 <alternatives>
  <graphic xlink:href="graphic/eq_002.png"/>
  <mml:math>
   <mml:mstyle displaystyle="true" scriptlevel="0">
    <mml:mi mathvariant="normal">&Delta;</mml:mi>
    <mml:mi>x</mml:mi>
    <mml:mi mathvariant="normal">&Delta;</mml:mi>
    <mml:mi>p</mml:mi>
    <mml:mo>&ge;</mml:mo>
    <mml:mfrac>
     <mml:mn>1</mml:mn>
     <mml:mn>2</mml:mn>
    </mml:mfrac>
    <mml:mi class="MJX-variant">&hbar;</mml:mi>
   </mml:mstyle>
  </mml:math>
 </alternatives>
</disp-formula>
...
Triple bond glyph
To a chemist, a triple bond is not the same character as Unicode x2261, but <alternatives> may be used to display the triple bond visually and still stay within Unicode.
...
<alternatives>

 <textual-form specific-use="unicode-look-alike">&#x2261;</textual-form>

 <private-char name="Triple Bond" description="Chemistry Triple Bond">
  <glyph-data id="tbond" format="PBM" resolution="300"
    x-size="16" y-size="32">
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0001111111111111111111111100000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0001111111111111111111111100000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0001111111111111111111111100000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
   0000000000000000000000000000000
  </glyph-data>
 </private-char>

</alternatives>
...
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