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layout: Introduce support for legacy presentational attributes to selector

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matching, and use it for `<input size>` and `<td width>`.

This implements a general framework for legacy presentational attributes
to the DOM and style calculation, so that adding more of them later will
be straightforward.
This commit is contained in:
Patrick Walton 2014-10-14 11:25:29 -07:00
parent 8077edc062
commit 5f8d3f72d8
31 changed files with 570 additions and 214 deletions
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16
components/style/properties/common_types.rs
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@ -24,6 +24,13 @@ pub mod specified {
Au_(Au), // application units
Em(CSSFloat),
Ex(CSSFloat),
/// HTML5 "character width", as defined in HTML5 § 14.5.4.
///
/// This cannot be specified by the user directly and is only generated by
/// `Stylist::synthesize_rules_for_legacy_attributes()`.
ServoCharacterWidth(i32),
// XXX uncomment when supported:
// Ch(CSSFloat),
// Rem(CSSFloat),
@ -245,6 +252,15 @@ pub mod computed {
let x_height = 0.5; // TODO: find that from the font
reference_font_size.scale_by(value * x_height)
},
specified::ServoCharacterWidth(value) => {
// This applies the *converting a character width to pixels* algorithm as specified
// in HTML5 § 14.5.4.
//
// TODO(pcwalton): Find these from the font.
let average_advance = reference_font_size.scale_by(0.5);
let max_advance = reference_font_size;
average_advance.scale_by(value as CSSFloat - 1.0) + max_advance
}
}
}