Package ro.sync.ecss.extensions.api

Interface StylesFilter

  • All Superinterfaces:
    Extension
    All Known Implementing Classes:
    GeneralStylesFilterExtension
    @API(type=EXTENDABLE,
     src=PUBLIC)
public interface StylesFilter
extends Extension

    Filter for the element styles. Use this to replace the CSS styles associated to an element or a pseudo element.

    oXygen supports multiple :before and :after pseudo elements. For example, the selector :before(2) represents a pseudo-element before a 'regular' :before, both of which are contained at the start of an element. The :before and :before(1) are equivalent.

    The following rules: 
      p { content: 'A' }
  p:before(1) { content: 'B'; }
  p:before(2) { content: 'C'; }
    Result in : 
      ,-----------------------.
  | ,---. ,---.           |
  | | C | | B | A         |
  | `---' `---'           |
  `-----------------------'

    So, an implementation of StylesFilter receives callbacks for:

    1. for each element from the document object model
    2. for each :before and :after pseudo-element, no matter if they were defined in the CSS or not for the parent element.
    3. for each :before(n) and :after(n), with n >= 2, pseudo-element, but only if they have been defined in the the CSS for the parent element.

    The level of the pseudo-element can be determined by using Styles.getPseudoLevel().

    Important: To use higher level pseudo elements (':before(n)', ':after(n)' with n >= 2) make sure you specify them in your CSS, having a content property. The content property specified for them can be later replaced by the StylesFilter.

    oXygen collects all the pseudo element levels from the CSS use these to probe the StylesFilter.

    For example, having the following CSS:

        
    body            { color:blue;}     
    div:before(300) { content: 'D300'}
    p:before(100)   { content: 'P100'}
    p:before        { content: 'P1'}
         
    a:before(5)     { content: 'A5'}

    And the XML document:

        <body>
      <div>
        <p>
          <a></a>
        </p>
      </div>
    </body>

    Your implementation will get callbacks like:

     
    filter(body, styles); 
    filter(before(body), styles);    // styles.pseudoLevel = 1;    // Always
    filter(after(body),  styles);    // styles.pseudoLevel = 1;    // Always
    
    filter(div, styles);                                           // Always
    filter(before(div),  styles);    // styles.pseudoLevel = 1;    // Always
    filter(before(div),  styles);    // styles.pseudoLevel = 300;  // Only if there is a div:before(300) with content in the CSSS.  
    filter(after(div, 1),styles);    // styles.pseudoLevel = 1;    // Always

    filter(p, styles);                                             // Always
    filter(before(p),    styles);    // styles.pseudoLevel = 1;    // Always
    filter(before(p),    styles);    // styles.pseudoLevel = 100;  // Only if there is a p:before(100) with content in the CSSS.
    filter(after(p),     styles);    // styles.pseudoLevel = 1;    // Always

    filter(a, styles);                                              // Always
    filter(before(a),    styles);     // styles.pseudoLevel = 1;    // Always
    filter(before(a),    styles);     // styles.pseudoLevel = 5;    // Only if there is a a:before(5) with content in the CSSS.
    filter(after(a),     styles);     // styles.pseudoLevel = 1;    // Always

    So for each element, each possible level will be probed.

    If your StylesFilter implementation also implements the AuthorExtensionStateListener API, its "activated" callback will be automatically called with the corresponding AuthorAccess.

    See Also:
    ExtensionsBundle

    • Method Detail

      • filter

        Styles filter​(Styles styles,
              AuthorNode authorNode)
        Filter the styles for the specified element. A common use-case is to change only some of the CSS properties from the original styles and keep the others. To this end, one should use Styles.setProperty(int, Object) on the original styles and return them.
        Parameters:
        styles - The original CSS styles associated with the specified authorNode. This object should only be used for the lifetime of the method. It shouldn't be kept in a cache.
        authorNode - The node to filter the CSS style for. If this node points to a processing instruction, a CDATA or a comment then the real node can be obtained by casting this object to ArtificialNode and using ArtificialNode.getWrappedNode(). The node can be part of the document object model, or a pseudo element (A :before or an :after). To obtain the pseudo level (distance of the pseudo element from its parent), use Styles.getPseudoLevel().
        Returns:
        The customized CSS style that will be associated with the given node. If the returned object is null then the original styles will be used.