Skip to content
phpdftk

phpdftk/css

CSS Syntax 3, Values 4, Selectors 4, Cascade 5 — pure PHP, no dependencies.

Terminal window
composer require phpdftk/css

Quick example

Section titled “Quick example”
use Phpdftk\Css\Parser;
use Phpdftk\Css\Cascade\Cascade;
use Phpdftk\Css\Cascade\PropertyRegistry;
use Phpdftk\Css\Sheet\Origin;


$sheet = (new Parser())->parseStylesheet(<<<'CSS'
:root { --brand: #ff8000; }


.button {
  padding: 0.5em 1em;
  background: var(--brand);
  color: white;
}


@media (min-width: 800px) {
  .button { padding: 0.75em 1.5em }
}
CSS, Origin::Author);


$cascade = new Cascade(PropertyRegistry::default());
$values = $cascade->computeFor([$sheet], $someElement);
$values->get('background-color');   // Phpdftk\Css\Value\Color(255, 128, 0)
$values->customProperties();        // ['--brand' => Color, ...]

What’s in the box

Section titled “What’s in the box”

Tokenizer (CSS Syntax 3 §4) — Full state machine over CSS code points: identifiers, hash, string (single + double + bad-string recovery), number, dimension, percentage, URL token (unquoted, quoted, bad-url recovery), at-keyword, function, whitespace, EOF. Handles comments, escape sequences, BOM stripping. Streaming token output.

Value parser (CSS Values 4) — Typed values: Length, Percentage, Color (sRGB, sRGB-linear, Display-P3, A98 RGB, ProPhoto RGB, Rec2020, XYZ, Lab, LCH, OKLab, OKLCH — with chroma gamut-mapping for wide-gamut→sRGB rendering), Keyword, Number, Integer, ValueList, Url, Calc, CustomProperty. Functional values: var(), calc()/min()/max()/clamp(), color()/color-mix(), rgb()/rgba()/hsl()/hsla()/hwb()/lab()/lch()/oklab()/oklch(), linear-gradient()/radial-gradient()/conic-gradient() plus repeating variants, attr(), env().

Selectors 4 — Compound selectors (type, class, id, attribute, pseudo-class, pseudo-element), combinators (descendant, child, adjacent-sibling, general-sibling), negation, :is(), :where(), :has(), :not(), structural pseudos (:nth-child(an+b), :first-child, :last-child, :only-child, :nth-of-type, :empty, :root), state pseudos (:hover, :focus, :checked, :disabled, :enabled — static-snapshot evaluation), ::before/::after/::first-line/::first-letter/::marker/::placeholder, attribute matchers (=, ~=, |=, ^=, $=, *=).

Cascade 5 — Origin precedence (user-agent → user → author → important reverses), specificity (a-b-c calculation including :is()/:where() rules), order of appearance, custom-property inheritance, computed-value resolution. !important, inherit, initial, unset, revert. Pseudo-class state handling.

@-rules — @media (full feature evaluation: min-width/max-width/orientation/color/color-index/device-pixel-ratio/prefers-*), @supports (full condition evaluation including selector(:has(.foo))), @import (with media query + supports condition gates), @font-face, @page (with margin boxes, named pages, @top-left-corner etc.), @keyframes (parsed; animation only for 0%/100% static frame), @counter-style, @property (registered custom properties with type checking), @layer (cascade layers).

Calc evaluator — calc() trees fold at cascade time when all leaves resolve against LengthContext alone. Mixed length+percentage trees defer to layout-time resolution against the per-property containing-block basis.

Why phpdftk/css

Section titled “Why phpdftk/css”
phpdftk/csssabberworm/php-css-parser
CSS Syntax 3 tokenizer✓ Full state machine~ Token recovery is approximate
Cascade resolution✓ Full (origin + specificity + order + !important)✗ Parse-only
Value computation✓ Computed values per property✗ Raw tokens
Selectors 4 matching✓ Full incl. :has() / :is() / :where()✗ No matcher
Modern color spaces✓ Display-P3, OKLCH, Lab, Rec2020, XYZ✗
calc() / var() resolution✓ At cascade time + layout time~ Token preservation
Property registry with typed values✓✗
@-rule support✓ media, supports, page, font-face, keyframes, layer, property~ Some

Status

Section titled “Status”

WPT pass-rate snapshots (in-scope subset for static-renderer + tagged-PDF):

ModulePass rateNote
css/css-variables/**97.79%Custom properties + var() + registered properties
css/css-pseudo/**94.58%::before/::after/::first-line/::first-letter/::marker
css/css-text/text-indent/**87.50%text-indent property
css/css-color/**86.67%Color parsing + colour-space conversion
css/css-overflow/**74.95%overflow / clip / scroll-marker
css/css-backgrounds/**72.59%bg-image / bg-color / borders / box-shadow

The full corpus result is documented in the rendering overview and updated per-commit by CI.

Security

Section titled “Security”

The parser does not fetch remote resources. url() references are exposed as Phpdftk\Css\Value\Url for the consumer to load — phpdftk/html-to-pdf gates them through phpdftk/resource-loader with SSRF + scheme allow-listing.

@import URLs are also exposed as references rather than auto-fetched; you wire the loader at the consumer site.

Roadmap

Section titled “Roadmap”

CSS work is shipped across the HTML/SVG rendering roadmap and the full-spec compliance plan. The remaining surface (@scope, cascade layers revert-layer, container queries) lives under Phase 5C.

☕ Support phpdftk