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CSS zef:dwarring last updated on 2022-06-22
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class CSS

CSS Stylesheet processing


    use CSS;
    use CSS::Properties;
    use CSS::Units :px; # define 'px' postfix operator
    use CSS::TagSet::XHTML;
    use LibXML::Document;

    my $string = q:to<\_(ツ)_/>;
      <!DOCTYPE html>
            @page :first { margin:4pt; }
            body {background-color: powderblue; font-size: 12pt}
            @media screen { h1:first-child {color: blue !important;} }
            @media print { h2 {color: green;} }
            p    {color: red; font-family:'Para';}
            div {font-size: 10pt }
            @font-face {
          <h1>This is a heading</h1>
          <h2>This is a sub-heading</h2>
          <h1>This is another heading</h1>
          <p>This is a paragraph.</p>
          <div style="color:green">This is a div</div>

    my LibXML::Document $doc .= parse: :$string, :html;

    # define a selection media
    my CSS::Media $media .= new: :type<screen>, :width(480px), :height(640px), :color;

    # Create a tag-set for XHTML specific loading of style-sheets and styling
    my CSS::TagSet::XHTML $tag-set .= new();

    my CSS $css .= new: :$doc, :$tag-set, :$media, :inherit;

    # -- show some computed styles, based on CSS Selectors, media, inline styles and xhtml tags
    my CSS::Properties $body-props = $'/html/body');
    say $body-props.font-size; # 12pt
    say $body-props;           # background-color:powderblue; display:block; font-size:12pt; margin:8px; unicode-bidi:embed;
    say $'/html/body/h1[1]');
    # color:blue; display:block; font-size:12pt; font-weight:bolder; margin-bottom:0.67em; margin-top:0.67em; unicode-bidi:embed;
    say $'/html/body/div');

    # color:green; display:block; font-size:10pt; unicode-bidi:embed;
    say $$doc.first('/html/body/div'));
    # color:green; display:block; font-size:10pt; unicode-bidi:embed;

    # -- query first page properties (from @page rules)
    say $;     # margin:4pt;

    # -- find a font using @font-face declarations
    say .Str    # font-family:'Para'; src:url('/myfonts/para.otf')
        with $css.font-sources('12pt Para').head;


[CSS]( is a module for parsing style-sheets and applying them to HTML or XML documents.

This module aims to be W3C compliant and complete, including: style-sheets, media specific and inline styling and the application of HTML specific styling (based on tags and attributes).


### method new

method new(
    LibXML::Document :$doc!,       # document to be styled.
    CSS::Stylesheet :$stylesheet!, # stylesheet to apply
    CSS::TagSet :$tag-set,         # tag-specific styling
    CSS::Media :$media,            # target media
    Bool :$inherit = True,         # perform property inheritance
    :%include (                    # External stylesheet loading:
        Bool :$imports = False,    # - enable '@import' directives
        Bool :$links = False,      # - load <link../> tags (XHTML)
    URI() :$base-url = $doc.URI,   # base URL for imports and links
) returns CSS;

In particular, the `CSS::TagSet :$tag-set` options specifies a tag-specific styler; For example CSS::TagSet::XHTML. 

### method style

multi method style(LibXML::Element:D $elem) returns CSS::Properties;
multi method style(Str:D $xpath) returns CSS::Properties;

Computes a style for an individual element, or XPath to an element.

### method page-properties

method page-properties(Bool :$first, Bool :$right, Bool :$left,
                       Str :$margin-box --> CSS::Properties)

Query and extract `@page` at rules.

The `:first`, `:right` and `:left` flags can be used to select rules applicable to a given logical page.

In addition, the `:margin-box` can be used to select a specific [Page Margin Box]( For example given the at-rule `@page { margin:2cm; size:a4; @top-center { content: 'Page ' counter(page); } }`, the top-center page box properties can be selected with `$<top-center>)`.

### method font-face

multi method font-face() returns Array[CSS::Font::Descriptor]
multi method font-face($family) returns CSS::Font::Descriptor

  * `font-face()` returns a list of all fonts declared with `@font-face` at-rules

  * `font-face($family)` returns font-properties for the given font-family;

### method prune

method prune(LibXML::Element $node? --> LibXML::Element)

Removes all XML nodes with CSS property `display:none;`, giving an approximate representation of a CSS rendering tree.

For example, if an HTML document with an XHTML tag-set is pruned the `head` element will be removed because it has the property `display:none;`. Any other elements that have had `display:none;' applied to them via the tag-set, inline CSS, or CSS Selectors are also removed.

By default, this method acts on the root element of the associated $.doc XML document.

### method font-sources

method font-sources(CSS::Font() $font) returns Array[CSS::Font::Resources::Source]

Returns a list of [CSS::Font::Resources::Source]( objects for natching source fonts, based on `@font-face` rules and (as a fallback) the font's name and characterstics.

Utility Scripts

  * `css-inliner.raku input.xml [output.xml] --style=file.css --prune --tags --type=html|pango|pdf --inherit`

Apply internal or external style-sheets to per-element 'style' attributes

See Also

  * [CSS::Stylesheet]( - CSS Stylesheet representations

  * [CSS::Module]( - CSS Module module

  * [CSS::Properties]( - CSS Properties module

  * [CSS::TagSet]( - CSS tag-sets (XHTML, Pango, Tagged PDF)

  * [LibXML]( - LibXML Raku module

  * [DOM::Tiny]( - A lightweight, self-contained DOM parser/manipulator


- Other At-Rule variants `@document`