servo/src/components/script/layout_interface.rs
Patrick Walton 7a435fc6ed Refactor document damage to distinguish it from layout/style damage.
Also, standardize on the name "reflow" instead of "relayout" or "build".
2013-06-04 22:00:33 -07:00

125 lines
4.3 KiB
Rust

/* 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 http://mozilla.org/MPL/2.0/. */
//! The high-level interface from script to layout. Using this abstract interface helps reduce
/// coupling between these two components, and enables the DOM to be placed in a separate crate
/// from layout.
use dom::node::{AbstractNode, ScriptView, LayoutView};
use script_task::ScriptMsg;
use core::comm::{Chan, SharedChan};
use geom::rect::Rect;
use geom::size::Size2D;
use geom::point::Point2D;
use gfx::geometry::Au;
use newcss::stylesheet::Stylesheet;
use std::net::url::Url;
/// Asynchronous messages that script can send to layout.
///
/// FIXME(pcwalton): I think this should probably be merged with `LayoutQuery` below.
pub enum Msg {
/// Adds the given stylesheet to the document.
AddStylesheetMsg(Stylesheet),
/// Requests a reflow.
ReflowMsg(~Reflow),
/// Performs a synchronous layout request.
///
/// FIXME(pcwalton): As noted below, this isn't very type safe.
QueryMsg(LayoutQuery, Chan<Result<LayoutResponse,()>>),
/// Requests that the layout task shut down and exit.
ExitMsg,
}
/// Synchronous messages that script can send to layout.
pub enum LayoutQuery {
/// Requests the dimensions of the content box, as in the `getBoundingClientRect()` call.
ContentBoxQuery(AbstractNode<ScriptView>),
/// Requests the dimensions of all the content boxes, as in the `getClientRects()` call.
ContentBoxesQuery(AbstractNode<ScriptView>),
/// Requests the node containing the point of interest
HitTestQuery(AbstractNode<ScriptView>, Point2D<f32>),
}
/// The reply of a synchronous message from script to layout.
///
/// FIXME(pcwalton): This isn't very type safe. Maybe `LayoutQuery` objects should include
/// response channels?
pub enum LayoutResponse {
/// A response to the `ContentBoxQuery` message.
ContentBoxResponse(Rect<Au>),
/// A response to the `ContentBoxesQuery` message.
ContentBoxesResponse(~[Rect<Au>]),
/// A response to the `HitTestQuery` message.
HitTestResponse(AbstractNode<LayoutView>),
}
/// Determines which part of the
pub enum DocumentDamageLevel {
/// Perform CSS selector matching and reflow.
MatchSelectorsDocumentDamage,
/// Reflow, but do not perform CSS selector matching.
ReflowDocumentDamage,
}
impl DocumentDamageLevel {
/// Sets this damage to the maximum of this damage and the given damage.
///
/// FIXME(pcwalton): This could be refactored to use `max` and the `Ord` trait, and this
/// function removed.
fn add(&mut self, new_damage: DocumentDamageLevel) {
match (*self, new_damage) {
(ReflowDocumentDamage, new_damage) => *self = new_damage,
(MatchSelectorsDocumentDamage, _) => *self = MatchSelectorsDocumentDamage,
}
}
}
/// What parts of the document have changed, as far as the script task can tell.
///
/// Note that this is fairly coarse-grained and is separate from layout's notion of the document
pub struct DocumentDamage {
/// The topmost node in the tree that has changed.
root: AbstractNode<ScriptView>,
/// The amount of damage that occurred.
level: DocumentDamageLevel,
}
/// Why we're doing reflow.
#[deriving(Eq)]
pub enum ReflowGoal {
/// We're reflowing in order to send a display list to the screen.
ReflowForDisplay,
/// We're reflowing in order to satisfy a script query. No display list will be created.
ReflowForScriptQuery,
}
/// Information needed for a reflow.
pub struct Reflow {
/// The document node.
document_root: AbstractNode<ScriptView>,
/// The style changes that need to be done.
damage: DocumentDamage,
/// The goal of reflow: either to render to the screen or to flush layout info for script.
goal: ReflowGoal,
/// The URL of the page.
url: Url,
/// The channel through which messages can be sent back to the script task.
script_chan: SharedChan<ScriptMsg>,
/// The current window size.
window_size: Size2D<uint>,
/// The channel that we send a notification to.
script_join_chan: Chan<()>,
}
/// Encapsulates a channel to the layout task.
#[deriving(Clone)]
pub struct LayoutTask {
chan: SharedChan<Msg>,
}