mirror of
https://github.com/mozilla/gecko-dev.git
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b11ee5a0ec
This is on top of https://github.com/servo/servo/pull/15928. Now that cascade() gets a Device ref, we can use the default computed values from there to avoid propagating that state all over the place. Source-Repo: https://github.com/servo/servo Source-Revision: 8c8edb8731dc01d254839d0922590fba72f278c6 --HG-- extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear extra : subtree_revision : 4da0b4a162f5987954a443b93f411e461ef0187d
808 lines
29 KiB
Rust
808 lines
29 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! The [`@viewport`][at] at-rule and [`meta`][meta] element.
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//!
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//! [at]: https://drafts.csswg.org/css-device-adapt/#atviewport-rule
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//! [meta]: https://drafts.csswg.org/css-device-adapt/#viewport-meta
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#![deny(missing_docs)]
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use app_units::Au;
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use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser, parse_important};
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use cssparser::ToCss as ParserToCss;
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use euclid::size::TypedSize2D;
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use media_queries::Device;
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use parser::{ParserContext, log_css_error};
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use std::ascii::AsciiExt;
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use std::borrow::Cow;
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use std::fmt;
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use std::iter::Enumerate;
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use std::str::Chars;
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use style_traits::{PinchZoomFactor, ToCss};
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use style_traits::viewport::{Orientation, UserZoom, ViewportConstraints, Zoom};
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use stylesheets::{Stylesheet, Origin};
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use values::computed::{Context, ToComputedValue};
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use values::specified::{NoCalcLength, LengthOrPercentageOrAuto, ViewportPercentageLength};
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macro_rules! declare_viewport_descriptor {
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( $( $variant_name: expr => $variant: ident($data: ident), )+ ) => {
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declare_viewport_descriptor_inner!([] [ $( $variant_name => $variant($data), )+ ] 0);
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};
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}
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macro_rules! declare_viewport_descriptor_inner {
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(
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[ $( $assigned_variant_name: expr =>
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$assigned_variant: ident($assigned_data: ident) = $assigned_discriminant: expr, )* ]
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[
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$next_variant_name: expr => $next_variant: ident($next_data: ident),
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$( $variant_name: expr => $variant: ident($data: ident), )*
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]
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$next_discriminant: expr
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) => {
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declare_viewport_descriptor_inner! {
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[
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$( $assigned_variant_name => $assigned_variant($assigned_data) = $assigned_discriminant, )*
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$next_variant_name => $next_variant($next_data) = $next_discriminant,
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]
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[ $( $variant_name => $variant($data), )* ]
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$next_discriminant + 1
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}
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};
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(
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[ $( $assigned_variant_name: expr =>
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$assigned_variant: ident($assigned_data: ident) = $assigned_discriminant: expr, )* ]
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[ ]
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$number_of_variants: expr
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) => {
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
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#[allow(missing_docs)]
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pub enum ViewportDescriptor {
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$(
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$assigned_variant($assigned_data),
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)+
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}
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const VIEWPORT_DESCRIPTOR_VARIANTS: usize = $number_of_variants;
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impl ViewportDescriptor {
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#[allow(missing_docs)]
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pub fn discriminant_value(&self) -> usize {
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match *self {
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$(
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ViewportDescriptor::$assigned_variant(..) => $assigned_discriminant,
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)*
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}
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}
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}
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impl ToCss for ViewportDescriptor {
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fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
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match *self {
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$(
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ViewportDescriptor::$assigned_variant(ref val) => {
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try!(dest.write_str($assigned_variant_name));
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try!(dest.write_str(": "));
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try!(val.to_css(dest));
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},
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)*
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}
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dest.write_str(";")
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}
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}
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};
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}
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declare_viewport_descriptor! {
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"min-width" => MinWidth(ViewportLength),
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"max-width" => MaxWidth(ViewportLength),
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"min-height" => MinHeight(ViewportLength),
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"max-height" => MaxHeight(ViewportLength),
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"zoom" => Zoom(Zoom),
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"min-zoom" => MinZoom(Zoom),
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"max-zoom" => MaxZoom(Zoom),
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"user-zoom" => UserZoom(UserZoom),
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"orientation" => Orientation(Orientation),
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}
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trait FromMeta: Sized {
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fn from_meta(value: &str) -> Option<Self>;
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}
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/// ViewportLength is a length | percentage | auto | extend-to-zoom
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/// See:
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/// * http://dev.w3.org/csswg/css-device-adapt/#min-max-width-desc
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/// * http://dev.w3.org/csswg/css-device-adapt/#extend-to-zoom
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
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#[allow(missing_docs)]
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pub enum ViewportLength {
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Specified(LengthOrPercentageOrAuto),
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ExtendToZoom
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}
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impl ToCss for ViewportLength {
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fn to_css<W>(&self, dest: &mut W) -> fmt::Result
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where W: fmt::Write,
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{
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match *self {
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ViewportLength::Specified(ref length) => length.to_css(dest),
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ViewportLength::ExtendToZoom => write!(dest, "extend-to-zoom"),
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}
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}
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}
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impl FromMeta for ViewportLength {
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fn from_meta(value: &str) -> Option<ViewportLength> {
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macro_rules! specified {
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($value:expr) => {
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ViewportLength::Specified(LengthOrPercentageOrAuto::Length($value))
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}
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}
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Some(match value {
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v if v.eq_ignore_ascii_case("device-width") =>
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specified!(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(100.))),
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v if v.eq_ignore_ascii_case("device-height") =>
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specified!(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vh(100.))),
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_ => {
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match value.parse::<f32>() {
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Ok(n) if n >= 0. => specified!(NoCalcLength::from_px(n.max(1.).min(10000.))),
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Ok(_) => return None,
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Err(_) => specified!(NoCalcLength::from_px(1.))
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}
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}
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})
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}
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}
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impl ViewportLength {
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fn parse(input: &mut Parser) -> Result<ViewportLength, ()> {
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// we explicitly do not accept 'extend-to-zoom', since it is a UA internal value
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// for <META> viewport translation
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LengthOrPercentageOrAuto::parse_non_negative(input).map(ViewportLength::Specified)
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}
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}
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impl FromMeta for Zoom {
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fn from_meta(value: &str) -> Option<Zoom> {
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Some(match value {
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v if v.eq_ignore_ascii_case("yes") => Zoom::Number(1.),
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v if v.eq_ignore_ascii_case("no") => Zoom::Number(0.1),
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v if v.eq_ignore_ascii_case("device-width") => Zoom::Number(10.),
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v if v.eq_ignore_ascii_case("device-height") => Zoom::Number(10.),
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_ => {
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match value.parse::<f32>() {
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Ok(n) if n >= 0. => Zoom::Number(n.max(0.1).min(10.)),
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Ok(_) => return None,
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Err(_) => Zoom::Number(0.1),
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}
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}
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})
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}
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}
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impl FromMeta for UserZoom {
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fn from_meta(value: &str) -> Option<UserZoom> {
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Some(match value {
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v if v.eq_ignore_ascii_case("yes") => UserZoom::Zoom,
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v if v.eq_ignore_ascii_case("no") => UserZoom::Fixed,
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v if v.eq_ignore_ascii_case("device-width") => UserZoom::Zoom,
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v if v.eq_ignore_ascii_case("device-height") => UserZoom::Zoom,
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_ => {
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match value.parse::<f32>() {
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Ok(n) if n >= 1. || n <= -1. => UserZoom::Zoom,
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_ => UserZoom::Fixed
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}
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}
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})
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}
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}
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struct ViewportRuleParser<'a, 'b: 'a> {
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context: &'a ParserContext<'b>
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}
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
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#[allow(missing_docs)]
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pub struct ViewportDescriptorDeclaration {
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pub origin: Origin,
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pub descriptor: ViewportDescriptor,
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pub important: bool
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}
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impl ViewportDescriptorDeclaration {
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#[allow(missing_docs)]
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pub fn new(origin: Origin,
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descriptor: ViewportDescriptor,
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important: bool) -> ViewportDescriptorDeclaration
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{
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ViewportDescriptorDeclaration {
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origin: origin,
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descriptor: descriptor,
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important: important
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}
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}
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}
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impl ToCss for ViewportDescriptorDeclaration {
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fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
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try!(self.descriptor.to_css(dest));
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if self.important {
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try!(dest.write_str(" !important"));
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}
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dest.write_str(";")
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}
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}
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fn parse_shorthand(input: &mut Parser) -> Result<(ViewportLength, ViewportLength), ()> {
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let min = try!(ViewportLength::parse(input));
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match input.try(|input| ViewportLength::parse(input)) {
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Err(()) => Ok((min.clone(), min)),
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Ok(max) => Ok((min, max))
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}
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}
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impl<'a, 'b> AtRuleParser for ViewportRuleParser<'a, 'b> {
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type Prelude = ();
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type AtRule = Vec<ViewportDescriptorDeclaration>;
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}
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impl<'a, 'b> DeclarationParser for ViewportRuleParser<'a, 'b> {
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type Declaration = Vec<ViewportDescriptorDeclaration>;
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fn parse_value(&mut self, name: &str, input: &mut Parser) -> Result<Vec<ViewportDescriptorDeclaration>, ()> {
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macro_rules! declaration {
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($declaration:ident($parse:path)) => {
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declaration!($declaration(value: try!($parse(input)),
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important: input.try(parse_important).is_ok()))
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};
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($declaration:ident(value: $value:expr, important: $important:expr)) => {
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ViewportDescriptorDeclaration::new(
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self.context.stylesheet_origin,
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ViewportDescriptor::$declaration($value),
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$important)
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}
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}
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macro_rules! ok {
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($declaration:ident($parse:path)) => {
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Ok(vec![declaration!($declaration($parse))])
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};
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(shorthand -> [$min:ident, $max:ident]) => {{
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let shorthand = try!(parse_shorthand(input));
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let important = input.try(parse_important).is_ok();
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Ok(vec![declaration!($min(value: shorthand.0, important: important)),
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declaration!($max(value: shorthand.1, important: important))])
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}}
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}
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match name {
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n if n.eq_ignore_ascii_case("min-width") =>
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ok!(MinWidth(ViewportLength::parse)),
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n if n.eq_ignore_ascii_case("max-width") =>
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ok!(MaxWidth(ViewportLength::parse)),
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n if n.eq_ignore_ascii_case("width") =>
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ok!(shorthand -> [MinWidth, MaxWidth]),
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n if n.eq_ignore_ascii_case("min-height") =>
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ok!(MinHeight(ViewportLength::parse)),
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n if n.eq_ignore_ascii_case("max-height") =>
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ok!(MaxHeight(ViewportLength::parse)),
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n if n.eq_ignore_ascii_case("height") =>
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ok!(shorthand -> [MinHeight, MaxHeight]),
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n if n.eq_ignore_ascii_case("zoom") =>
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ok!(Zoom(Zoom::parse)),
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n if n.eq_ignore_ascii_case("min-zoom") =>
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ok!(MinZoom(Zoom::parse)),
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n if n.eq_ignore_ascii_case("max-zoom") =>
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ok!(MaxZoom(Zoom::parse)),
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n if n.eq_ignore_ascii_case("user-zoom") =>
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ok!(UserZoom(UserZoom::parse)),
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n if n.eq_ignore_ascii_case("orientation") =>
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ok!(Orientation(Orientation::parse)),
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_ => Err(()),
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}
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}
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}
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/// A `@viewport` rule.
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#[derive(Debug, PartialEq)]
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#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
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pub struct ViewportRule {
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/// The declarations contained in this @viewport rule.
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pub declarations: Vec<ViewportDescriptorDeclaration>
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}
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/// Whitespace as defined by DEVICE-ADAPT § 9.2
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// TODO: should we just use whitespace as defined by HTML5?
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const WHITESPACE: &'static [char] = &['\t', '\n', '\r', ' '];
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/// Separators as defined by DEVICE-ADAPT § 9.2
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// need to use \x2c instead of ',' due to test-tidy
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const SEPARATOR: &'static [char] = &['\x2c', ';'];
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#[inline]
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fn is_whitespace_separator_or_equals(c: &char) -> bool {
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WHITESPACE.contains(c) || SEPARATOR.contains(c) || *c == '='
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}
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impl ViewportRule {
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#[allow(missing_docs)]
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pub fn parse(input: &mut Parser, context: &ParserContext)
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-> Result<ViewportRule, ()>
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{
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let parser = ViewportRuleParser { context: context };
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let mut cascade = Cascade::new();
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let mut parser = DeclarationListParser::new(input, parser);
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while let Some(result) = parser.next() {
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match result {
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Ok(declarations) => {
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for declarations in declarations {
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cascade.add(Cow::Owned(declarations))
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}
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}
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Err(range) => {
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let pos = range.start;
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let message = format!("Unsupported @viewport descriptor declaration: '{}'",
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parser.input.slice(range));
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log_css_error(parser.input, pos, &*message, &context);
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}
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}
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}
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Ok(ViewportRule { declarations: cascade.finish() })
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}
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#[allow(missing_docs)]
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pub fn from_meta(content: &str) -> Option<ViewportRule> {
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let mut declarations = vec![None; VIEWPORT_DESCRIPTOR_VARIANTS];
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macro_rules! push_descriptor {
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($descriptor:ident($value:expr)) => {{
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let descriptor = ViewportDescriptor::$descriptor($value);
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let discriminant = descriptor.discriminant_value();
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declarations[discriminant] = Some(ViewportDescriptorDeclaration::new(
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Origin::Author,
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descriptor,
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false));
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}
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}}
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let mut has_width = false;
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let mut has_height = false;
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let mut has_zoom = false;
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let mut iter = content.chars().enumerate();
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macro_rules! start_of_name {
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($iter:ident) => {
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$iter.by_ref()
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.skip_while(|&(_, c)| is_whitespace_separator_or_equals(&c))
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.next()
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}
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}
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while let Some((start, _)) = start_of_name!(iter) {
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let property = ViewportRule::parse_meta_property(content,
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&mut iter,
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start);
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if let Some((name, value)) = property {
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macro_rules! push {
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($descriptor:ident($translate:path)) => {
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if let Some(value) = $translate(value) {
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push_descriptor!($descriptor(value));
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}
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}
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}
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match name {
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n if n.eq_ignore_ascii_case("width") => {
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if let Some(value) = ViewportLength::from_meta(value) {
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push_descriptor!(MinWidth(ViewportLength::ExtendToZoom));
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push_descriptor!(MaxWidth(value));
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has_width = true;
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}
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}
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n if n.eq_ignore_ascii_case("height") => {
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if let Some(value) = ViewportLength::from_meta(value) {
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push_descriptor!(MinHeight(ViewportLength::ExtendToZoom));
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push_descriptor!(MaxHeight(value));
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has_height = true;
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}
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}
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n if n.eq_ignore_ascii_case("initial-scale") => {
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if let Some(value) = Zoom::from_meta(value) {
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push_descriptor!(Zoom(value));
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has_zoom = true;
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}
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}
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n if n.eq_ignore_ascii_case("minimum-scale") =>
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push!(MinZoom(Zoom::from_meta)),
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n if n.eq_ignore_ascii_case("maximum-scale") =>
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push!(MaxZoom(Zoom::from_meta)),
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n if n.eq_ignore_ascii_case("user-scalable") =>
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push!(UserZoom(UserZoom::from_meta)),
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_ => {}
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}
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}
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}
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// DEVICE-ADAPT § 9.4 - The 'width' and 'height' properties
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// http://dev.w3.org/csswg/css-device-adapt/#width-and-height-properties
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if !has_width && has_zoom {
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if has_height {
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push_descriptor!(MinWidth(ViewportLength::Specified(LengthOrPercentageOrAuto::Auto)));
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push_descriptor!(MaxWidth(ViewportLength::Specified(LengthOrPercentageOrAuto::Auto)));
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} else {
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push_descriptor!(MinWidth(ViewportLength::ExtendToZoom));
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push_descriptor!(MaxWidth(ViewportLength::ExtendToZoom));
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}
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}
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let declarations: Vec<_> = declarations.into_iter().filter_map(|entry| entry).collect();
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if !declarations.is_empty() {
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Some(ViewportRule { declarations: declarations })
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} else {
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None
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}
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}
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fn parse_meta_property<'a>(content: &'a str,
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iter: &mut Enumerate<Chars<'a>>,
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start: usize)
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-> Option<(&'a str, &'a str)>
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{
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fn end_of_token(iter: &mut Enumerate<Chars>) -> Option<(usize, char)> {
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iter.by_ref()
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.skip_while(|&(_, c)| !is_whitespace_separator_or_equals(&c))
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.next()
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}
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fn skip_whitespace(iter: &mut Enumerate<Chars>) -> Option<(usize, char)> {
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iter.by_ref()
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.skip_while(|&(_, c)| WHITESPACE.contains(&c))
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.next()
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}
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|
|
// <name> <whitespace>* '='
|
|
let end = match end_of_token(iter) {
|
|
Some((end, c)) if WHITESPACE.contains(&c) => {
|
|
match skip_whitespace(iter) {
|
|
Some((_, c)) if c == '=' => end,
|
|
_ => return None
|
|
}
|
|
}
|
|
Some((end, c)) if c == '=' => end,
|
|
_ => return None
|
|
};
|
|
let name = &content[start..end];
|
|
|
|
// <whitespace>* <value>
|
|
let start = match skip_whitespace(iter) {
|
|
Some((start, c)) if !SEPARATOR.contains(&c) => start,
|
|
_ => return None
|
|
};
|
|
let value = match end_of_token(iter) {
|
|
Some((end, _)) => &content[start..end],
|
|
_ => &content[start..]
|
|
};
|
|
|
|
Some((name, value))
|
|
}
|
|
}
|
|
|
|
impl ToCss for ViewportRule {
|
|
// Serialization of ViewportRule is not specced.
|
|
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
|
|
try!(dest.write_str("@viewport { "));
|
|
let mut iter = self.declarations.iter();
|
|
try!(iter.next().unwrap().to_css(dest));
|
|
for declaration in iter {
|
|
try!(dest.write_str(" "));
|
|
try!(declaration.to_css(dest));
|
|
}
|
|
dest.write_str(" }")
|
|
}
|
|
}
|
|
|
|
/// Computes the cascade precedence as according to
|
|
/// http://dev.w3.org/csswg/css-cascade/#cascade-origin
|
|
fn cascade_precendence(origin: Origin, important: bool) -> u8 {
|
|
match (origin, important) {
|
|
(Origin::UserAgent, true) => 1,
|
|
(Origin::User, true) => 2,
|
|
(Origin::Author, true) => 3,
|
|
(Origin::Author, false) => 4,
|
|
(Origin::User, false) => 5,
|
|
(Origin::UserAgent, false) => 6,
|
|
}
|
|
}
|
|
|
|
impl ViewportDescriptorDeclaration {
|
|
fn higher_or_equal_precendence(&self, other: &ViewportDescriptorDeclaration) -> bool {
|
|
let self_precedence = cascade_precendence(self.origin, self.important);
|
|
let other_precedence = cascade_precendence(other.origin, other.important);
|
|
|
|
self_precedence <= other_precedence
|
|
}
|
|
}
|
|
|
|
#[allow(missing_docs)]
|
|
pub struct Cascade {
|
|
declarations: Vec<Option<(usize, ViewportDescriptorDeclaration)>>,
|
|
count_so_far: usize,
|
|
}
|
|
|
|
#[allow(missing_docs)]
|
|
impl Cascade {
|
|
pub fn new() -> Self {
|
|
Cascade {
|
|
declarations: vec![None; VIEWPORT_DESCRIPTOR_VARIANTS],
|
|
count_so_far: 0,
|
|
}
|
|
}
|
|
|
|
pub fn from_stylesheets<'a, I>(stylesheets: I, device: &Device) -> Self
|
|
where I: IntoIterator,
|
|
I::Item: AsRef<Stylesheet>,
|
|
{
|
|
let mut cascade = Self::new();
|
|
for stylesheet in stylesheets {
|
|
stylesheet.as_ref().effective_viewport_rules(device, |rule| {
|
|
for declaration in &rule.declarations {
|
|
cascade.add(Cow::Borrowed(declaration))
|
|
}
|
|
})
|
|
}
|
|
cascade
|
|
}
|
|
|
|
pub fn add(&mut self, declaration: Cow<ViewportDescriptorDeclaration>) {
|
|
let descriptor = declaration.descriptor.discriminant_value();
|
|
|
|
match self.declarations[descriptor] {
|
|
Some((ref mut order_of_appearance, ref mut entry_declaration)) => {
|
|
if declaration.higher_or_equal_precendence(entry_declaration) {
|
|
*entry_declaration = declaration.into_owned();
|
|
*order_of_appearance = self.count_so_far;
|
|
}
|
|
}
|
|
ref mut entry @ None => {
|
|
*entry = Some((self.count_so_far, declaration.into_owned()));
|
|
}
|
|
}
|
|
self.count_so_far += 1;
|
|
}
|
|
|
|
pub fn finish(mut self) -> Vec<ViewportDescriptorDeclaration> {
|
|
// sort the descriptors by order of appearance
|
|
self.declarations.sort_by_key(|entry| entry.as_ref().map(|&(index, _)| index));
|
|
self.declarations.into_iter().filter_map(|entry| entry.map(|(_, decl)| decl)).collect()
|
|
}
|
|
}
|
|
|
|
/// Just a helper trait to be able to implement methods on ViewportConstraints.
|
|
pub trait MaybeNew {
|
|
/// Create a ViewportConstraints from a viewport size and a `@viewport`
|
|
/// rule.
|
|
fn maybe_new(device: &Device,
|
|
rule: &ViewportRule)
|
|
-> Option<ViewportConstraints>;
|
|
}
|
|
|
|
impl MaybeNew for ViewportConstraints {
|
|
fn maybe_new(device: &Device,
|
|
rule: &ViewportRule)
|
|
-> Option<ViewportConstraints>
|
|
{
|
|
use std::cmp;
|
|
|
|
if rule.declarations.is_empty() {
|
|
return None
|
|
}
|
|
|
|
let mut min_width = None;
|
|
let mut max_width = None;
|
|
|
|
let mut min_height = None;
|
|
let mut max_height = None;
|
|
|
|
let mut initial_zoom = None;
|
|
let mut min_zoom = None;
|
|
let mut max_zoom = None;
|
|
|
|
let mut user_zoom = UserZoom::Zoom;
|
|
let mut orientation = Orientation::Auto;
|
|
|
|
// collapse the list of declarations into descriptor values
|
|
for declaration in &rule.declarations {
|
|
match declaration.descriptor {
|
|
ViewportDescriptor::MinWidth(ref value) => min_width = Some(value),
|
|
ViewportDescriptor::MaxWidth(ref value) => max_width = Some(value),
|
|
|
|
ViewportDescriptor::MinHeight(ref value) => min_height = Some(value),
|
|
ViewportDescriptor::MaxHeight(ref value) => max_height = Some(value),
|
|
|
|
ViewportDescriptor::Zoom(value) => initial_zoom = value.to_f32(),
|
|
ViewportDescriptor::MinZoom(value) => min_zoom = value.to_f32(),
|
|
ViewportDescriptor::MaxZoom(value) => max_zoom = value.to_f32(),
|
|
|
|
ViewportDescriptor::UserZoom(value) => user_zoom = value,
|
|
ViewportDescriptor::Orientation(value) => orientation = value
|
|
}
|
|
}
|
|
|
|
// TODO: return `None` if all descriptors are either absent or initial value
|
|
|
|
macro_rules! choose {
|
|
($op:ident, $opta:expr, $optb:expr) => {
|
|
match ($opta, $optb) {
|
|
(None, None) => None,
|
|
(a, None) => a,
|
|
(None, b) => b,
|
|
(Some(a), Some(b)) => Some(a.$op(b)),
|
|
}
|
|
}
|
|
}
|
|
macro_rules! min {
|
|
($opta:expr, $optb:expr) => {
|
|
choose!(min, $opta, $optb)
|
|
}
|
|
}
|
|
macro_rules! max {
|
|
($opta:expr, $optb:expr) => {
|
|
choose!(max, $opta, $optb)
|
|
}
|
|
}
|
|
|
|
// DEVICE-ADAPT § 6.2.1 Resolve min-zoom and max-zoom values
|
|
if min_zoom.is_some() && max_zoom.is_some() {
|
|
max_zoom = Some(min_zoom.unwrap().max(max_zoom.unwrap()))
|
|
}
|
|
|
|
// DEVICE-ADAPT § 6.2.2 Constrain zoom value to the [min-zoom, max-zoom] range
|
|
if initial_zoom.is_some() {
|
|
initial_zoom = max!(min_zoom, min!(max_zoom, initial_zoom));
|
|
}
|
|
|
|
// DEVICE-ADAPT § 6.2.3 Resolve non-auto lengths to pixel lengths
|
|
//
|
|
// Note: DEVICE-ADAPT § 5. states that relative length values are
|
|
// resolved against initial values
|
|
let initial_viewport = device.au_viewport_size();
|
|
|
|
// TODO(emilio): Stop cloning `ComputedValues` around!
|
|
let context = Context {
|
|
is_root_element: false,
|
|
device: device,
|
|
inherited_style: device.default_computed_values(),
|
|
layout_parent_style: device.default_computed_values(),
|
|
style: device.default_computed_values().clone(),
|
|
font_metrics_provider: None, // TODO: Should have!
|
|
};
|
|
|
|
// DEVICE-ADAPT § 9.3 Resolving 'extend-to-zoom'
|
|
let extend_width;
|
|
let extend_height;
|
|
if let Some(extend_zoom) = max!(initial_zoom, max_zoom) {
|
|
let scale_factor = 1. / extend_zoom;
|
|
extend_width = Some(initial_viewport.width.scale_by(scale_factor));
|
|
extend_height = Some(initial_viewport.height.scale_by(scale_factor));
|
|
} else {
|
|
extend_width = None;
|
|
extend_height = None;
|
|
}
|
|
|
|
macro_rules! to_pixel_length {
|
|
($value:ident, $dimension:ident, $extend_to:ident => $auto_extend_to:expr) => {
|
|
if let Some($value) = $value {
|
|
match *$value {
|
|
ViewportLength::Specified(ref length) => match *length {
|
|
LengthOrPercentageOrAuto::Length(ref value) =>
|
|
Some(value.to_computed_value(&context)),
|
|
LengthOrPercentageOrAuto::Percentage(value) =>
|
|
Some(initial_viewport.$dimension.scale_by(value.0)),
|
|
LengthOrPercentageOrAuto::Auto => None,
|
|
LengthOrPercentageOrAuto::Calc(ref calc) => {
|
|
let calc = calc.to_computed_value(&context);
|
|
Some(initial_viewport.$dimension.scale_by(calc.percentage()) + calc.length())
|
|
}
|
|
},
|
|
ViewportLength::ExtendToZoom => {
|
|
// $extend_to will be 'None' if 'extend-to-zoom' is 'auto'
|
|
match ($extend_to, $auto_extend_to) {
|
|
(None, None) => None,
|
|
(a, None) => a,
|
|
(None, b) => b,
|
|
(a, b) => cmp::max(a, b)
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
// DEVICE-ADAPT § 9.3 states that max-descriptors need to be resolved
|
|
// before min-descriptors.
|
|
// http://dev.w3.org/csswg/css-device-adapt/#resolve-extend-to-zoom
|
|
let max_width = to_pixel_length!(max_width, width, extend_width => None);
|
|
let max_height = to_pixel_length!(max_height, height, extend_height => None);
|
|
|
|
let min_width = to_pixel_length!(min_width, width, extend_width => max_width);
|
|
let min_height = to_pixel_length!(min_height, height, extend_height => max_height);
|
|
|
|
// DEVICE-ADAPT § 6.2.4 Resolve initial width and height from min/max descriptors
|
|
macro_rules! resolve {
|
|
($min:ident, $max:ident, $initial:expr) => {
|
|
if $min.is_some() || $max.is_some() {
|
|
let max = match $max {
|
|
Some(max) => cmp::min(max, $initial),
|
|
None => $initial
|
|
};
|
|
|
|
Some(match $min {
|
|
Some(min) => cmp::max(min, max),
|
|
None => max
|
|
})
|
|
} else {
|
|
None
|
|
};
|
|
}
|
|
}
|
|
|
|
let width = resolve!(min_width, max_width, initial_viewport.width);
|
|
let height = resolve!(min_height, max_height, initial_viewport.height);
|
|
|
|
// DEVICE-ADAPT § 6.2.5 Resolve width value
|
|
let width = if width.is_none() && height.is_none() {
|
|
Some(initial_viewport.width)
|
|
} else {
|
|
width
|
|
};
|
|
|
|
let width = width.unwrap_or_else(|| match initial_viewport.height {
|
|
Au(0) => initial_viewport.width,
|
|
initial_height => {
|
|
let ratio = initial_viewport.width.to_f32_px() / initial_height.to_f32_px();
|
|
Au::from_f32_px(height.unwrap().to_f32_px() * ratio)
|
|
}
|
|
});
|
|
|
|
// DEVICE-ADAPT § 6.2.6 Resolve height value
|
|
let height = height.unwrap_or_else(|| match initial_viewport.width {
|
|
Au(0) => initial_viewport.height,
|
|
initial_width => {
|
|
let ratio = initial_viewport.height.to_f32_px() / initial_width.to_f32_px();
|
|
Au::from_f32_px(width.to_f32_px() * ratio)
|
|
}
|
|
});
|
|
|
|
Some(ViewportConstraints {
|
|
size: TypedSize2D::new(width.to_f32_px(), height.to_f32_px()),
|
|
|
|
// TODO: compute a zoom factor for 'auto' as suggested by DEVICE-ADAPT § 10.
|
|
initial_zoom: PinchZoomFactor::new(initial_zoom.unwrap_or(1.)),
|
|
min_zoom: min_zoom.map(PinchZoomFactor::new),
|
|
max_zoom: max_zoom.map(PinchZoomFactor::new),
|
|
|
|
user_zoom: user_zoom,
|
|
orientation: orientation
|
|
})
|
|
}
|
|
}
|