We are now creating the basic layout of the rendered documents.

Elements that are stacked one on top of the other are: book, article, section, title, figure, table, image. These elements are marked as having block style for display. Elements that are placed one after the other in a flowing sequence are: b, i. These will have inline display.

/* Vertical flow */
book,
section,
para,
title,
image,
ref {
    display:block;
}

/* Horizontal flow */
b,i {
    display:inline;
}

	Important
	Having block display children in an inline display parent, makes oXygen Author change the style of the parent to block display.

The title of any section must be bold and smaller than the title of the parent section. To create this effect we have to create a sequence of CSS rules. The * operator matches any element, so we can use it to match titles having progressive depths in the document.

title{
    font-size: 2.4em;
    font-weight:bold;    
}
* * title{
    font-size: 2.0em;
}
* * * title{
    font-size: 1.6em;
}
* * * * title{
    font-size: 1.2em;
}

Note

CSS rules are combined as follows: All the rules that match an element are kept as a list. The more specific the rule is, the further it will be placed to the end of the list. If there is no difference in the specificity of the rules, they are placed in the list in the same order as they appear in the CSS document. The list is then iterated, and all the properties from the rules are collected, overwriting the already collected values from the previous rules. That is why the font-size is changed depending on the depth of the element, while the font-weight property remains unchanged - no other rule is overwriting it.

It's useful to have before the title a constant text, indicating that it refers to a section. This text can include also the current section number. To achieve we have to use the :before and :after pseudo elements, plus the CSS counters.

We declare a counter named sect for each book or article. The counter is set to zero at the beginning of each such element:

book, 
article{
    counter-reset:sect;
}
                        

The sect counter is incremented with each section, that is the a direct child of a book or an article element.

book > section,
article > section{
    counter-increment:sect;
}   

The "static" text that will prefix the section title is composed of the constant "Section ", followed by the decimal value of the sect counter and a dot.

book > section > title:before,
article > section > title:before{
    content: "Section " counter(sect) ". ";
}

To make the documents easy to read, we will add a margin to the sections. In this way the higher nesting level, the larger the left side indent. The margin is expressed relatively to the parent bounds:

section{
    margin-left:1em;
    margin-top:1em;
}

Figure 7.3. A sample of nested sections and their titles.

In the above screenshot you can see a sample XML document rendered by our CSS. The selection "avoids" the text that is generated by the CSS "content" property. This happens because the CSS generated text is not present in the XML document and is just a visual aid.

There are standard CSS properties used to indicate what elements are tables, table rows and table cells. What CSS is missing is the possibility to indicate the cell spanning. oXygen Author offers support for adding an extension to solve this problem. This will be presented in the next chapters.

The table in this example is a simple one. The header must be formatted in a different way than the ordinary rows, so it will have a background color.

table{
    display:table;
    border:1px solid navy;
    margin:1em;
}

tr, header{
    display:table-row;
}

header{
    background-color: silver;
    color:inherit
}

td{
  display:table-cell;
  border:1px solid navy;
  padding:1em;
}

	Note
	Children elements with block or table-caption display placed at the beginning or the end of an element displayed as a table, will be grouped and presented as blocks at the top or the bottom of the table.

	Note
	Mixing elements having table-cell, table-group, table-row, etc.. display type with others that have block or inline display or with text content breaks the layout of the table. In such cases the table is shown as a block.

	Note
	Having child elements that do not have table-cell or table display in a parent with table-row display breaks the table layout. In this case the table display is supported for the children of the table-row element in order to allow sub-tables in the parent table.

Note

oXygen Author can automatically detect the spanning of a cell, without the need to write a Java extension for this. This happens if the span of the cell element is specified using the colspan and rowspan attributes, just like in HTML, or cols and rows attributes. For instance, the following XML code: <table> <tr> <td>Cell 1.1</td> <td>Cell 1.2</td> <td>Cell 1.3</td> </tr> <tr> <td>Cell 2.1</td> <td colspan="2" rowspan="2"> Cell spanning 2 rows and 2 columns. </td> </tr> <tr><td>Cell 3.1</td></tr> </table> using the CSS: table{ display: table; } tr{ display: table-row; } td{ display: table-cell; } is rendered correctly: Table 7.1. Built-in Cell Spanning Cell 1.1 Cell 1.2 Cell 1.3 Cell 2.1 Cell spanning 2 rows and 2 columns Cell 3.1

Because in our schema the td tag has the attributes row_span and column_span that are not automatically recognized by oXygen Author, we will implement a Java extension which will provide information about the cell spanning. See the section Configuring a Table Cell Span Provider.

The "bold" style is obtained by using the font-weight CSS property with the value bold, while the "italic" style is specified by the font-style property:

b {
    font-weight:bold;
}

i {
    font-style:italic;
}

In the CSS Level 1, 2, and 2.1 there is no way to specify if an element X from the namespace Y should be presented differently from the element X from the namespace Z. In the upcoming CSS Level 3, it is possible to differentiate elements by their namespaces. oXygen Author supports this CSS Level 3 functionality. For more information see the Namespace Selectors section.

To match our def element we will declare its namespace, bind it to the abs prefix, and then write a CSS rule:

@namespace abs "http://www.oxygenxml.com/sample/documentation/abstracts";

abs|def{
    font-family:monospace;
    font-size:smaller;    
}
abs|def:before{
    content:"Definition:";
    color:gray;
}

The CSS 2.1 does not specify how an element can be rendered as an image. To overpass this limitation, oXygen Author supports a CSS Level 3 extension allowing to load image data from an URL. The URL of the image must be specified by one of the element attributes.

	Note
	oXygen Author recognizes the following image file formats: JPEG, GIF, PNG and SVG. The oXygen Author for Eclipse does not render the SVG files.

image{
    display:block;
    content: attr(href, url);
    margin-left:2em;
}

Our image element has the required attribute href of type xs:anyURI. The href attribute contains an image location so the rendered content is obtained by using the function:

attr(href, url)

	Important
	The first argument is the name of the attribute pointing to the image file. The second argument of the attr function specifies the type of the content. If the type has the url value, then oXygen identifies the content as being an image. If the type is missing, then the content will be the text representing the attribute value.

Important

oXygen Author handles both absolute and relative specified URLs. If the image has an absolute URL location (e.g: "http://www.oasis-open.org/images/standards/oasis_standard.jpg") then it is loaded directly from this location. If the image URL is relative specified to the XML document (e.g: "images/my_screenshot.jpg") then the location is obtained by adding this value to the location of the edited XML document.

An image can also be referenced by the name of a DTD entity which specifies the location of the image file. For example if the document declares an entity graphic which points to a JPEG image file:

<!ENTITY graphic SYSTEM "depo/keyboard_shortcut.jpg" NDATA JPEG>

and the image is referenced in the XML document by specifying the name of the entity as the value of an attribute:

<mediaobject>
    <imageobject>
        <imagedata entityref="graphic" scale="50"/>
    </imageobject>
</mediaobject>

the CSS should use the functions url, attr and unparsed-entity-uri for displaying the image in the Author mode:

imagedata[entityref]{
    content: url(unparsed-entity-uri(attr(entityref))); 
}

Figure 7.4. Samples of images in Author

You can specify what elements are collapsible. The collapsible elements are rendered having a small triangle icon in the top left corner. Clicking on this icon hides or shows the children of the element. In our case, we will mark the section elements as foldable. We will leave only the title child elements visible.

section{
    foldable:true;
    not-foldable-child: title;
}

Figure 7.5. Folded Sections

You can specify what elements are links. The text content specified in the :before pseudo element will be underlined. When hovering the mouse over that content the mouse pointer will change to indicate that it can follow the link. Clicking on a link will result in the referred resource being opened in an editor. In our case we will mark the link elements as links with the href attribute indicating the referred location.

link[href]:before{
    display:inline;
    link:attr(href);
    content: "Click to open: " attr(href);
}

Note

If you plan to use IDs as references for links, the value of the link property should start with a sharp sign(#). This will ensure that the default link target reference finder implementation will work and clicking on the link will send you to the indicated location in the document. For more details about the link target reference finder read the section Configuring a Link target reference finder. Example 7.1. IDs as references for links link[linkend]:before{ display:inline; link: "#" attr(linkend); content: "Click to open: " attr(linkend); }

First create a new folder called sdf (from "Simple Documentation Framework") in {oXygen_installation_directory}/frameworks. We will use this folder to store all files related to our documentation framework. Let's organise it a bit, by creating the following folder structure:

oxygen
  frameworks
     sdf
       schema
       css

	Important
	The frameworks directory is the container where all the oXygen framework customizations are located. Each subdirectory contains files related to a specific type of XML documents: schemas, catalogs, stylesheets, CSS files, etc. Distributing a framework means delivering a framework directory.

Important

We assume you have the right to create files and folder inside the oXygen installation directory. If you do not have this right, you will have to install another copy of the program in a folder you have access to, the home directory for instance, or your desktop. You can download the "all platforms" distribution from the oXygen website and extract it in the chosen folder. To test your framework distribution you will need to copy it in the frameworks directory of the newly installed application and start oXygen by running the provided start-up script files.

We should copy the created schema files abs.xsd and sdf.xsd, sdf.xsd being the master schema, to the schema directory and the CSS file sdf.css to the css directory.

We must specify when oXygen should use the files created in the previous section by creating a document type association. Open the Document Type dialog by following the procedure:

In the displayed dialog, fill in the following data:

In the dialog for editing the Document Type properties, in the bottom section there are a series of tabs. The first one refers to the schema that is used for validation of the documents that match the defined association Rules.

	Important
	If the document refers a schema, using for instance a DOCTYPE declaration or a xsi:schemaLocation attribute, the schema from the document type association will not be used when validating.

Figure 7.10. The Schema panel

Select the Author tab from the Document Type edit dialog. By clicking on the CSS label in the right part of the tab the list of associated CSS files is shown.

Here you can also specify how should the CSSs defined in the document type be treated when there are CSSs specified in the document(with xml-stylesheet processing instructions). The CSSs from the document can either replace the CSSs defined in the document type association or merge with them.

Add the URI of the CSS file sdf.css we already defined. We should use the ${frameworks} editor variable in the file path.

Figure 7.11. CSS settings dialog

The Title text field refers to a symbolic name for the stylesheet. When adding several stylesheets with different titles to a Document Type association, the content author can select what CSS will be used for editing from the Author CSS Alternatives toolbar.

This combo-box from the toolbar is also populated in case your XML document refers CSS files directly using xml-stylesheet processing instructions, and the processing instructions define titles for the CSS files.

	Note
	The CSS settings dialog allows to create a virtual xml-stylesheet processing instructions. The CSS files defined in the Document Type Association dialog and the xml-stylesheet processing instructions from the XML document are processed together, as being all a list of processing instructions.

oXygen Author fully implements the W3C recommendation regarding "Associating Style Sheets with XML documents". For more information see: http://www.w3.org/TR/xml-stylesheet/ http://www.w3.org/TR/REC-html40/present/styles.html#h-14.3.2

To test the new Document Type create an XML instance that is conforming with our Simple Document Format. We will not specify an XML Schema location directly in the document, using an xsi:schemaLocation attribute; oXygen will detect instead its associated document type and use the specified schema.

<book xmlns="http://www.oxygenxml.com/sample/documentation" 
      xmlns:abs="http://www.oxygenxml.com/sample/documentation/abstracts">

    <title>My Technical Book</title>
    <section>
        <title>XML</title>
        <abs:def>Extensible Markup Language</abs:def>
        <para>In this section of the book I will 
           explain different XML applications.</para>
    </section>
</book>

When trying to validate the document there should be no errors. Now modify the title to title2. Validate again. This time there should be one error:

  cvc-complex-type.2.4.a: Invalid content was found starting with element 
  'title2'. One of '{"http://www.oxygenxml.com/sample/documentation":title}' 
  is expected.

Undo the tag name change. Press on the Author button at the bottom of the editing area. oXygen should load the CSS from the document type association and create a layout similar to this:

Using a file explorer, go to the oXygen frameworks directory. Select the sdf directory and make an archive from it. Move it to another oXygen installation (eventually on another computer). Extract it in the frameworks directory. Start oXygen and test the association as explained above.

If you create multiple document type associations and you have a complex directory structure it might be easy from the deployment point of view to use an oXygen all platforms distribution. Add your framework files to it, repackage it and send it to the content authors.

Warning

When deploying your customized sdf directory please make sure that your sdf directory contains the sdf.framework file (that is the file defined as External Storage in Document Type Association dialog shall always be stored inside the sdf directory). If your external storage points somewhere else <oXygen/> will not be able to update the Document Type Association options automatically on the deployed computers.