<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, as well as encoded in TeX, and as a plain ASCII. These graphics may be loose inside a paragraph or enclosed in a structure such as a figure. The related element <block-alternatives> holds multiple copies of larger block-level-only structures such as figures and tables.
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.
Related Elements
Alternatives Inside a Structure: The <alternatives> element is used inside a single figure, table, or similar block structure to hold several versions of the content for the single figure, table, etc. For example, a single table could contain a graphic, a MathML-tagged equation, and a LaTeX-tagged equation as processing alternatives (inside the <alternatives> element).
Block-level Alternatives: In contrast, <block-alternatives> is used to hold more than one table (figure, etc.) when there are multiple tables (<table-wrap>) which must be treated as equivalent processing alternatives, for example, to hold two or more versions of a table or figure, each in a different language.
Attributes

Base Attributes

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

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

Tagged Samples
Alternative figure graphics, differentiated by usage
... 
<fig id="f3" position="float">
 <label>FIG. 3.</label>
 <caption>...</caption>
 <alternatives>
  <graphic specific-use="print" xlink:href="1.4821168.figures.highres.f3.zip"/>
  <graphic specific-use="online" xlink:href="1.4821168.figures.online.f3.jpg"/>
 </alternatives>
</fig>
...
Alternatives to a table inside <table-wrap>
One tagged XML and two graphical alternatives
...
<table-wrap id="pbio-0020328-t003" position="float">
 <label>Table 3</label>
 <caption>
  <title>Systematic Inactivation of SpoIIID-Activated Genes</title>
 </caption>
 <alternatives>

  <graphic xlink:href="pbio.0020328.t003.tif"/>

  <graphic xlink:href="pbio.0020328.t003.gif"/>

  <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>
    <tr>
     <td>PY79</td>
     <td>wild type</td>
     <td>100</td>
    </tr>
    <tr>
     <td>RL2391</td>
     <td><italic>asnO&Delta;::spc</italic></td>
     <td>0.000001</td>
    </tr>
    <tr>
     <td>PE563</td>
     <td><italic>cotF&Delta;::cat</italic></td>
     <td>83</td>
    </tr>
    ...
   </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:mo>=</mml:mo>
    ...    
   </mml:mrow>
  </mml:math>
  <graphic xlink:href="pbio.0020328.e001.gif"/>
 </alternatives>
</disp-formula>
...
Equation alternatives (TeX)
One tagged MathML, one in TeX, and one graphical
...
<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>
  <tex-math><![CDATA[\displaystyle \Delta x \Delta p \geq \frac{1}{2} \hbar]]></tex-math>
 </alternatives>
</disp-formula>
...
Media alternatives, differentiated by mime subtypes
...
<fig id="f1" orientation="portrait" position="float">
 <label>FIG. 1.</label>
 <caption>
  <p>(a) Schematic of the working principles of HFM, (b) a typical application
   scheme for an electric bias in HFM, (c) regulation the conformations and
   dynamics (trapping, concentration, and sudden stretching) of λ-DNA molecules
   in HFM, and (d) schematic of the trapping location regulation (enhanced online).
   [URL: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1063/1.4762852.1">
   http://dx.doi.org/10.1063/1.4762852.1</ext-link>]
   <alternatives>
    <media id="v1" mime-subtype="avi" mimetype="video" orientation="portrait"
      position="anchor" specific-use="original-format"
      xlink:href="v1-video1-orig.avi"/>
    <media mime-subtype="mpeg" mimetype="video" orientation="portrait"
      position="anchor" specific-use="archival-format"
      xlink:href="v1-video1-archive.mpeg"/>
    <media mime-subtype="x-flv" mimetype="video" orientation="portrait"
      position="anchor" specific-use="online-format"
      xlink:href="v1-video1-online.xfiv"/>
   </alternatives>
  </p>
 </caption>
 <graphic orientation="portrait" position="float" xlink:href="f1"/>
 <graphic id="f1a" orientation="portrait" position="float"
    xlink:href="dummy1.png"/>
 <graphic id="f1b" orientation="portrait" position="float"
    xlink:href="dummy2.png"/>
 <graphic id="f1c" orientation="portrait" position="float"
     xlink:href="dummy3.png"/>
 <graphic id="f1d" orientation="portrait" position="float"
     xlink:href="dummy4.png"/>
</fig>
...
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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