diff options
Diffstat (limited to 'servo/components/style/servo/media_queries.rs')
| -rw-r--r-- | servo/components/style/servo/media_queries.rs | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/servo/components/style/servo/media_queries.rs b/servo/components/style/servo/media_queries.rs new file mode 100644 index 0000000000..83b12f5ff2 --- /dev/null +++ b/servo/components/style/servo/media_queries.rs @@ -0,0 +1,226 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +//! Servo's media-query device and expression representation. + +use crate::context::QuirksMode; +use crate::custom_properties::CssEnvironment; +use crate::media_queries::media_feature::{AllowsRanges, ParsingRequirements}; +use crate::media_queries::media_feature::{Evaluator, MediaFeatureDescription}; +use crate::media_queries::media_feature_expression::RangeOrOperator; +use crate::media_queries::MediaType; +use crate::properties::ComputedValues; +use crate::values::computed::CSSPixelLength; +use crate::values::specified::font::FONT_MEDIUM_PX; +use crate::values::KeyframesName; +use app_units::Au; +use euclid::default::Size2D as UntypedSize2D; +use euclid::{Scale, SideOffsets2D, Size2D}; +use std::sync::atomic::{AtomicBool, AtomicU32, Ordering}; +use style_traits::{CSSPixel, DevicePixel}; + +/// A device is a structure that represents the current media a given document +/// is displayed in. +/// +/// This is the struct against which media queries are evaluated. +#[derive(Debug, MallocSizeOf)] +pub struct Device { + /// The current media type used by de device. + media_type: MediaType, + /// The current viewport size, in CSS pixels. + viewport_size: Size2D<f32, CSSPixel>, + /// The current device pixel ratio, from CSS pixels to device pixels. + device_pixel_ratio: Scale<f32, CSSPixel, DevicePixel>, + /// The current quirks mode. + #[ignore_malloc_size_of = "Pure stack type"] + quirks_mode: QuirksMode, + + /// The font size of the root element + /// This is set when computing the style of the root + /// element, and used for rem units in other elements + /// + /// When computing the style of the root element, there can't be any + /// other style being computed at the same time, given we need the style of + /// the parent to compute everything else. So it is correct to just use + /// a relaxed atomic here. + #[ignore_malloc_size_of = "Pure stack type"] + root_font_size: AtomicU32, + /// Whether any styles computed in the document relied on the root font-size + /// by using rem units. + #[ignore_malloc_size_of = "Pure stack type"] + used_root_font_size: AtomicBool, + /// Whether any styles computed in the document relied on the viewport size. + #[ignore_malloc_size_of = "Pure stack type"] + used_viewport_units: AtomicBool, + /// The CssEnvironment object responsible of getting CSS environment + /// variables. + environment: CssEnvironment, +} + +impl Device { + /// Trivially construct a new `Device`. + pub fn new( + media_type: MediaType, + quirks_mode: QuirksMode, + viewport_size: Size2D<f32, CSSPixel>, + device_pixel_ratio: Scale<f32, CSSPixel, DevicePixel>, + ) -> Device { + Device { + media_type, + viewport_size, + device_pixel_ratio, + quirks_mode, + // FIXME(bz): Seems dubious? + root_font_size: AtomicU32::new(FONT_MEDIUM_PX.to_bits()), + used_root_font_size: AtomicBool::new(false), + used_viewport_units: AtomicBool::new(false), + environment: CssEnvironment, + } + } + + /// Get the relevant environment to resolve `env()` functions. + #[inline] + pub fn environment(&self) -> &CssEnvironment { + &self.environment + } + + /// Return the default computed values for this device. + pub fn default_computed_values(&self) -> &ComputedValues { + // FIXME(bz): This isn't really right, but it's no more wrong + // than what we used to do. See + // https://github.com/servo/servo/issues/14773 for fixing it properly. + ComputedValues::initial_values() + } + + /// Get the font size of the root element (for rem) + pub fn root_font_size(&self) -> CSSPixelLength { + self.used_root_font_size.store(true, Ordering::Relaxed); + CSSPixelLength::new(f32::from_bits(self.root_font_size.load(Ordering::Relaxed))) + } + + /// Set the font size of the root element (for rem) + pub fn set_root_font_size(&self, size: CSSPixelLength) { + self.root_font_size + .store(size.px().to_bits(), Ordering::Relaxed) + } + + /// Get the quirks mode of the current device. + pub fn quirks_mode(&self) -> QuirksMode { + self.quirks_mode + } + + /// Sets the body text color for the "inherit color from body" quirk. + /// + /// <https://quirks.spec.whatwg.org/#the-tables-inherit-color-from-body-quirk> + pub fn set_body_text_color(&self, _color: RGBA) { + // Servo doesn't implement this quirk (yet) + } + + /// Whether a given animation name may be referenced from style. + pub fn animation_name_may_be_referenced(&self, _: &KeyframesName) -> bool { + // Assume it is, since we don't have any good way to prove it's not. + true + } + + /// Returns whether we ever looked up the root font size of the Device. + pub fn used_root_font_size(&self) -> bool { + self.used_root_font_size.load(Ordering::Relaxed) + } + + /// Returns the viewport size of the current device in app units, needed, + /// among other things, to resolve viewport units. + #[inline] + pub fn au_viewport_size(&self) -> UntypedSize2D<Au> { + Size2D::new( + Au::from_f32_px(self.viewport_size.width), + Au::from_f32_px(self.viewport_size.height), + ) + } + + /// Like the above, but records that we've used viewport units. + pub fn au_viewport_size_for_viewport_unit_resolution(&self) -> UntypedSize2D<Au> { + self.used_viewport_units.store(true, Ordering::Relaxed); + self.au_viewport_size() + } + + /// Whether viewport units were used since the last device change. + pub fn used_viewport_units(&self) -> bool { + self.used_viewport_units.load(Ordering::Relaxed) + } + + /// Returns the device pixel ratio. + pub fn device_pixel_ratio(&self) -> Scale<f32, CSSPixel, DevicePixel> { + self.device_pixel_ratio + } + + /// Return the media type of the current device. + pub fn media_type(&self) -> MediaType { + self.media_type.clone() + } + + /// Returns whether document colors are enabled. + pub fn use_document_colors(&self) -> bool { + true + } + + /// Returns the default background color. + pub fn default_background_color(&self) -> RGBA { + RGBA::new(255, 255, 255, 255) + } + + /// Returns the default color color. + pub fn default_color(&self) -> RGBA { + RGBA::new(0, 0, 0, 255) + } + + /// Returns safe area insets + pub fn safe_area_insets(&self) -> SideOffsets2D<f32, CSSPixel> { + SideOffsets2D::zero() + } +} + +/// https://drafts.csswg.org/mediaqueries-4/#width +fn eval_width( + device: &Device, + value: Option<CSSPixelLength>, + range_or_operator: Option<RangeOrOperator>, +) -> bool { + RangeOrOperator::evaluate( + range_or_operator, + value.map(Au::from), + device.au_viewport_size().width, + ) +} + +#[derive(Clone, Copy, Debug, FromPrimitive, Parse, ToCss)] +#[repr(u8)] +enum Scan { + Progressive, + Interlace, +} + +/// https://drafts.csswg.org/mediaqueries-4/#scan +fn eval_scan(_: &Device, _: Option<Scan>) -> bool { + // Since we doesn't support the 'tv' media type, the 'scan' feature never + // matches. + false +} + +lazy_static! { + /// A list with all the media features that Servo supports. + pub static ref MEDIA_FEATURES: [MediaFeatureDescription; 2] = [ + feature!( + atom!("width"), + AllowsRanges::Yes, + Evaluator::Length(eval_width), + ParsingRequirements::empty(), + ), + feature!( + atom!("scan"), + AllowsRanges::No, + keyword_evaluator!(eval_scan, Scan), + ParsingRequirements::empty(), + ), + ]; +} |