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Diffstat (limited to 'servo/components/style/values/animated/grid.rs')
| -rw-r--r-- | servo/components/style/values/animated/grid.rs | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/servo/components/style/values/animated/grid.rs b/servo/components/style/values/animated/grid.rs new file mode 100644 index 0000000000..8136ba5ece --- /dev/null +++ b/servo/components/style/values/animated/grid.rs @@ -0,0 +1,157 @@ +/* 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/. */ + +//! Animation implementation for various grid-related types. + +// Note: we can implement Animate on their generic types directly, but in this case we need to +// make sure two trait bounds, L: Clone and I: PartialEq, are satisfied on almost all the +// grid-related types and their other trait implementations because Animate needs them. So in +// order to avoid adding these two trait bounds (or maybe more..) everywhere, we implement +// Animate for the computed types, instead of the generic types. + +use super::{Animate, Procedure, ToAnimatedZero}; +use crate::values::computed::Integer; +use crate::values::computed::LengthPercentage; +use crate::values::computed::{GridTemplateComponent, TrackList, TrackSize}; +use crate::values::distance::{ComputeSquaredDistance, SquaredDistance}; +use crate::values::generics::grid as generics; + +fn discrete<T: Clone>(from: &T, to: &T, procedure: Procedure) -> Result<T, ()> { + if let Procedure::Interpolate { progress } = procedure { + Ok(if progress < 0.5 { + from.clone() + } else { + to.clone() + }) + } else { + Err(()) + } +} + +fn animate_with_discrete_fallback<T: Animate + Clone>( + from: &T, + to: &T, + procedure: Procedure, +) -> Result<T, ()> { + from.animate(to, procedure) + .or_else(|_| discrete(from, to, procedure)) +} + +impl Animate for TrackSize { + fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> { + match (self, other) { + (&generics::TrackSize::Breadth(ref from), &generics::TrackSize::Breadth(ref to)) => { + animate_with_discrete_fallback(from, to, procedure) + .map(generics::TrackSize::Breadth) + }, + ( + &generics::TrackSize::Minmax(ref from_min, ref from_max), + &generics::TrackSize::Minmax(ref to_min, ref to_max), + ) => Ok(generics::TrackSize::Minmax( + animate_with_discrete_fallback(from_min, to_min, procedure)?, + animate_with_discrete_fallback(from_max, to_max, procedure)?, + )), + ( + &generics::TrackSize::FitContent(ref from), + &generics::TrackSize::FitContent(ref to), + ) => animate_with_discrete_fallback(from, to, procedure) + .map(generics::TrackSize::FitContent), + (_, _) => discrete(self, other, procedure), + } + } +} + +impl Animate for generics::TrackRepeat<LengthPercentage, Integer> { + fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> { + // If the keyword, auto-fit/fill, is the same it can result in different + // number of tracks. For both auto-fit/fill, the number of columns isn't + // known until you do layout since it depends on the container size, item + // placement and other factors, so we cannot do the correct interpolation + // by computed values. Therefore, return Err(()) if it's keywords. If it + // is Number, we support animation only if the count is the same and the + // length of track_sizes is the same. + // https://github.com/w3c/csswg-drafts/issues/3503 + match (&self.count, &other.count) { + (&generics::RepeatCount::Number(from), &generics::RepeatCount::Number(to)) + if from == to => + { + () + }, + (_, _) => return Err(()), + } + + let count = self.count; + let track_sizes = super::lists::by_computed_value::animate( + &self.track_sizes, + &other.track_sizes, + procedure, + )?; + + // The length of |line_names| is always 0 or N+1, where N is the length + // of |track_sizes|. Besides, <line-names> is always discrete. + let line_names = discrete(&self.line_names, &other.line_names, procedure)?; + + Ok(generics::TrackRepeat { + count, + line_names, + track_sizes, + }) + } +} + +impl Animate for TrackList { + // Based on https://github.com/w3c/csswg-drafts/issues/3201: + // 1. Check interpolation type per track, so we need to handle discrete animations + // in TrackSize, so any Err(()) returned from TrackSize doesn't make all TrackSize + // fallback to discrete animation. + // 2. line-names is always discrete. + fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> { + if self.values.len() != other.values.len() { + return Err(()); + } + + if self.is_explicit() != other.is_explicit() { + return Err(()); + } + + // For now, repeat(auto-fill/auto-fit, ...) is not animatable. + // TrackRepeat will return Err(()) if we use keywords. Therefore, we can + // early return here to avoid traversing |values| in <auto-track-list>. + // This may be updated in the future. + // https://github.com/w3c/csswg-drafts/issues/3503 + if self.has_auto_repeat() || other.has_auto_repeat() { + return Err(()); + } + + let values = + super::lists::by_computed_value::animate(&self.values, &other.values, procedure)?; + + // The length of |line_names| is always 0 or N+1, where N is the length + // of |track_sizes|. Besides, <line-names> is always discrete. + let line_names = discrete(&self.line_names, &other.line_names, procedure)?; + + Ok(TrackList { + values, + line_names, + auto_repeat_index: self.auto_repeat_index, + }) + } +} + +impl ComputeSquaredDistance for GridTemplateComponent { + #[inline] + fn compute_squared_distance(&self, _other: &Self) -> Result<SquaredDistance, ()> { + // TODO: Bug 1518585, we should implement ComputeSquaredDistance. + Err(()) + } +} + +impl ToAnimatedZero for GridTemplateComponent { + #[inline] + fn to_animated_zero(&self) -> Result<Self, ()> { + // It's not clear to get a zero grid track list based on the current definition + // of spec, so we return Err(()) directly. + Err(()) + } +} |