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servo/components/layout/fragment.rs
Simon Sapin d5dd1d658e Upgrade to rustc ba2f13ef0 2015-02-04
2015-02-11 14:48:34 -08:00

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/* 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 `Fragment` type, which represents the leaves of the layout tree.
#![deny(unsafe_blocks)]
use canvas::canvas_paint_task::CanvasMsg;
use css::node_style::StyledNode;
use construct::FlowConstructor;
use context::LayoutContext;
use floats::ClearType;
use flow;
use flow::Flow;
use flow_ref::FlowRef;
use incremental::RestyleDamage;
use inline::{InlineFragmentContext, InlineMetrics};
use layout_debug;
use model::{IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto, specified};
use model;
use text;
use util::OpaqueNodeMethods;
use wrapper::{TLayoutNode, ThreadSafeLayoutNode};
use geom::{Point2D, Rect, Size2D};
use gfx::display_list::{BOX_SHADOW_INFLATION_FACTOR, OpaqueNode};
use gfx::text::glyph::CharIndex;
use gfx::text::text_run::{TextRun, TextRunSlice};
use script_traits::UntrustedNodeAddress;
use serialize::{Encodable, Encoder};
use msg::constellation_msg::{PipelineId, SubpageId};
use net::image::holder::ImageHolder;
use net::local_image_cache::LocalImageCache;
use servo_util::geometry::{self, Au, ZERO_POINT};
use servo_util::logical_geometry::{LogicalRect, LogicalSize, LogicalMargin};
use servo_util::range::*;
use servo_util::smallvec::SmallVec;
use servo_util::str::is_whitespace;
use std::borrow::ToOwned;
use std::cmp::{max, min};
use std::collections::DList;
use std::fmt;
use std::num::ToPrimitive;
use std::str::FromStr;
use std::sync::{Arc, Mutex};
use std::sync::mpsc::Sender;
use string_cache::Atom;
use style::properties::{ComputedValues, cascade_anonymous};
use style::node::{TElement, TNode};
use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto, LengthOrPercentageOrNone};
use style::computed_values::{clear, mix_blend_mode, overflow_wrap};
use style::computed_values::{position, text_align, text_decoration, vertical_align, white_space};
use style::computed_values::{word_break};
use text::TextRunScanner;
use url::Url;
/// Fragments (`struct Fragment`) are the leaves of the layout tree. They cannot position
/// themselves. In general, fragments do not have a simple correspondence with CSS fragments in the
/// specification:
///
/// * Several fragments may correspond to the same CSS box or DOM node. For example, a CSS text box
/// broken across two lines is represented by two fragments.
///
/// * Some CSS fragments are not created at all, such as some anonymous block fragments induced by
/// inline fragments with block-level sibling fragments. In that case, Servo uses an `InlineFlow`
/// with `BlockFlow` siblings; the `InlineFlow` is block-level, but not a block container. It is
/// positioned as if it were a block fragment, but its children are positioned according to
/// inline flow.
///
/// A `SpecificFragmentInfo::Generic` is an empty fragment that contributes only borders, margins,
/// padding, and backgrounds. It is analogous to a CSS nonreplaced content box.
///
/// A fragment's type influences how its styles are interpreted during layout. For example,
/// replaced content such as images are resized differently from tables, text, or other content.
/// Different types of fragments may also contain custom data; for example, text fragments contain
/// text.
///
/// Do not add fields to this structure unless they're really really mega necessary! Fragments get
/// moved around a lot and thus their size impacts performance of layout quite a bit.
///
/// FIXME(#2260, pcwalton): This can be slimmed down some by (at least) moving `inline_context`
/// to be on `InlineFlow` only.
#[derive(Clone)]
pub struct Fragment {
/// An opaque reference to the DOM node that this `Fragment` originates from.
pub node: OpaqueNode,
/// The CSS style of this fragment.
pub style: Arc<ComputedValues>,
/// The position of this fragment relative to its owning flow. The size includes padding and
/// border, but not margin.
///
/// NB: This does not account for relative positioning.
pub border_box: LogicalRect<Au>,
/// The sum of border and padding; i.e. the distance from the edge of the border box to the
/// content edge of the fragment.
pub border_padding: LogicalMargin<Au>,
/// The margin of the content box.
pub margin: LogicalMargin<Au>,
/// Info specific to the kind of fragment. Keep this enum small.
pub specific: SpecificFragmentInfo,
/// Holds the style context information for fragments
/// that are part of an inline formatting context.
pub inline_context: Option<InlineFragmentContext>,
/// A debug ID that is consistent for the life of
/// this fragment (via transform etc).
pub debug_id: u16,
/// How damaged this fragment is since last reflow.
pub restyle_damage: RestyleDamage,
}
unsafe impl Send for Fragment {}
unsafe impl Sync for Fragment {}
impl Encodable for Fragment {
fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
e.emit_struct("fragment", 0, |e| {
try!(e.emit_struct_field("id", 0, |e| self.debug_id().encode(e)));
try!(e.emit_struct_field("border_box", 1, |e| self.border_box.encode(e)));
e.emit_struct_field("margin", 2, |e| self.margin.encode(e))
})
}
}
/// Info specific to the kind of fragment.
///
/// Keep this enum small. As in, no more than one word. Or pcwalton will yell at you.
#[derive(Clone)]
pub enum SpecificFragmentInfo {
Generic,
Iframe(Box<IframeFragmentInfo>),
Image(Box<ImageFragmentInfo>),
Canvas(Box<CanvasFragmentInfo>),
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was
/// declared with `display: inline;`.
InlineAbsoluteHypothetical(InlineAbsoluteHypotheticalFragmentInfo),
InlineBlock(InlineBlockFragmentInfo),
ScannedText(Box<ScannedTextFragmentInfo>),
Table,
TableCell,
TableColumn(TableColumnFragmentInfo),
TableRow,
TableWrapper,
UnscannedText(UnscannedTextFragmentInfo),
}
impl SpecificFragmentInfo {
fn restyle_damage(&self) -> RestyleDamage {
let flow =
match *self {
SpecificFragmentInfo::Iframe(_)
| SpecificFragmentInfo::Image(_)
| SpecificFragmentInfo::ScannedText(_)
| SpecificFragmentInfo::Table
| SpecificFragmentInfo::TableCell
| SpecificFragmentInfo::TableColumn(_)
| SpecificFragmentInfo::TableRow
| SpecificFragmentInfo::TableWrapper
| SpecificFragmentInfo::UnscannedText(_)
| SpecificFragmentInfo::Canvas(_)
| SpecificFragmentInfo::Generic => return RestyleDamage::empty(),
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref info) => &info.flow_ref,
SpecificFragmentInfo::InlineBlock(ref info) => &info.flow_ref,
};
flow::base(&**flow).restyle_damage
}
pub fn get_type(&self) -> &'static str {
match *self {
SpecificFragmentInfo::Canvas(_) => "SpecificFragmentInfo::Canvas",
SpecificFragmentInfo::Generic => "SpecificFragmentInfo::Generic",
SpecificFragmentInfo::Iframe(_) => "SpecificFragmentInfo::Iframe",
SpecificFragmentInfo::Image(_) => "SpecificFragmentInfo::Image",
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => "SpecificFragmentInfo::InlineAbsoluteHypothetical",
SpecificFragmentInfo::InlineBlock(_) => "SpecificFragmentInfo::InlineBlock",
SpecificFragmentInfo::ScannedText(_) => "SpecificFragmentInfo::ScannedText",
SpecificFragmentInfo::Table => "SpecificFragmentInfo::Table",
SpecificFragmentInfo::TableCell => "SpecificFragmentInfo::TableCell",
SpecificFragmentInfo::TableColumn(_) => "SpecificFragmentInfo::TableColumn",
SpecificFragmentInfo::TableRow => "SpecificFragmentInfo::TableRow",
SpecificFragmentInfo::TableWrapper => "SpecificFragmentInfo::TableWrapper",
SpecificFragmentInfo::UnscannedText(_) => "SpecificFragmentInfo::UnscannedText",
}
}
}
/// Clamp a value obtained from style_length, based on min / max lengths.
fn clamp_size(size: Au, min_size: LengthOrPercentage, max_size: LengthOrPercentageOrNone,
container_inline_size: Au) -> Au {
let min_size = model::specified(min_size, container_inline_size);
let max_size = model::specified_or_none(max_size, container_inline_size);
Au::max(min_size, match max_size {
None => size,
Some(max_size) => Au::min(size, max_size),
})
}
/// A hypothetical box (see CSS 2.1 § 10.3.7) for an absolutely-positioned block that was declared
/// with `display: inline;`.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineAbsoluteHypotheticalFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineAbsoluteHypotheticalFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineAbsoluteHypotheticalFragmentInfo {
InlineAbsoluteHypotheticalFragmentInfo {
flow_ref: flow_ref,
}
}
}
/// A fragment that represents an inline-block element.
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineBlockFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineBlockFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineBlockFragmentInfo {
InlineBlockFragmentInfo {
flow_ref: flow_ref,
}
}
}
#[derive(Clone)]
pub struct CanvasFragmentInfo {
pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
pub renderer: Option<Arc<Mutex<Sender<CanvasMsg>>>>,
}
impl CanvasFragmentInfo {
pub fn new(node: &ThreadSafeLayoutNode) -> CanvasFragmentInfo {
CanvasFragmentInfo {
replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node,
Some(Au::from_px(node.get_canvas_width() as int)),
Some(Au::from_px(node.get_canvas_height() as int))),
renderer: node.get_renderer().map(|rec| Arc::new(Mutex::new(rec))),
}
}
/// Returns the original inline-size of the canvas.
pub fn canvas_inline_size(&self) -> Au {
self.replaced_image_fragment_info.dom_inline_size.unwrap_or(Au(0))
}
/// Returns the original block-size of the canvas.
pub fn canvas_block_size(&self) -> Au {
self.replaced_image_fragment_info.dom_block_size.unwrap_or(Au(0))
}
}
/// A fragment that represents a replaced content image and its accompanying borders, shadows, etc.
#[derive(Clone)]
pub struct ImageFragmentInfo {
/// The image held within this fragment.
pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
pub image: ImageHolder<UntrustedNodeAddress>,
}
impl ImageFragmentInfo {
/// Creates a new image fragment from the given URL and local image cache.
///
/// FIXME(pcwalton): The fact that image fragments store the cache in the fragment makes little
/// sense to me.
pub fn new(node: &ThreadSafeLayoutNode,
image_url: Url,
local_image_cache: Arc<Mutex<LocalImageCache<UntrustedNodeAddress>>>)
-> ImageFragmentInfo {
fn convert_length(node: &ThreadSafeLayoutNode, name: &Atom) -> Option<Au> {
let element = node.as_element();
element.get_attr(&ns!(""), name).and_then(|string| {
let n: Option<int> = FromStr::from_str(string).ok();
n
}).and_then(|pixels| Some(Au::from_px(pixels)))
}
ImageFragmentInfo {
replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node,
convert_length(node, &atom!("width")),
convert_length(node, &atom!("height"))),
image: ImageHolder::new(image_url, local_image_cache)
}
}
/// Returns the original inline-size of the image.
pub fn image_inline_size(&mut self) -> Au {
let size = self.image.get_size(self.replaced_image_fragment_info.for_node).unwrap_or(Size2D::zero());
Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical { size.height }
else { size.width })
}
/// Returns the original block-size of the image.
pub fn image_block_size(&mut self) -> Au {
let size = self.image.get_size(self.replaced_image_fragment_info.for_node).unwrap_or(Size2D::zero());
Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical { size.width }
else { size.height })
}
/// Tile an image
pub fn tile_image(position: &mut Au, size: &mut Au,
virtual_position: Au, image_size: u32) {
let image_size = image_size as int;
let delta_pixels = geometry::to_px(virtual_position - *position);
let tile_count = (delta_pixels + image_size - 1) / image_size;
let offset = Au::from_px(image_size * tile_count);
let new_position = virtual_position - offset;
*size = *position - new_position + *size;
*position = new_position;
}
}
#[derive(Clone)]
pub struct ReplacedImageFragmentInfo {
pub for_node: UntrustedNodeAddress,
pub computed_inline_size: Option<Au>,
pub computed_block_size: Option<Au>,
pub dom_inline_size: Option<Au>,
pub dom_block_size: Option<Au>,
pub writing_mode_is_vertical: bool,
}
impl ReplacedImageFragmentInfo {
pub fn new(node: &ThreadSafeLayoutNode,
dom_width: Option<Au>,
dom_height: Option<Au>) -> ReplacedImageFragmentInfo {
let is_vertical = node.style().writing_mode.is_vertical();
let opaque_node: OpaqueNode = OpaqueNodeMethods::from_thread_safe_layout_node(node);
let untrusted_node: UntrustedNodeAddress = opaque_node.to_untrusted_node_address();
ReplacedImageFragmentInfo {
for_node: untrusted_node,
computed_inline_size: None,
computed_block_size: None,
dom_inline_size: if is_vertical { dom_height } else { dom_width },
dom_block_size: if is_vertical { dom_width } else { dom_height },
writing_mode_is_vertical: is_vertical,
}
}
/// Returns the calculated inline-size of the image, accounting for the inline-size attribute.
pub fn computed_inline_size(&self) -> Au {
self.computed_inline_size.expect("image inline_size is not computed yet!")
}
/// Returns the calculated block-size of the image, accounting for the block-size attribute.
pub fn computed_block_size(&self) -> Au {
self.computed_block_size.expect("image block_size is not computed yet!")
}
// Return used value for inline-size or block-size.
//
// `dom_length`: inline-size or block-size as specified in the `img` tag.
// `style_length`: inline-size as given in the CSS
pub fn style_length(style_length: LengthOrPercentageOrAuto,
dom_length: Option<Au>,
container_inline_size: Au) -> MaybeAuto {
match (MaybeAuto::from_style(style_length,container_inline_size),dom_length) {
(MaybeAuto::Specified(length),_) => {
MaybeAuto::Specified(length)
},
(MaybeAuto::Auto,Some(length)) => {
MaybeAuto::Specified(length)
},
(MaybeAuto::Auto,None) => {
MaybeAuto::Auto
}
}
}
pub fn calculate_replaced_inline_size(&mut self,
style: ComputedValues,
noncontent_inline_size: Au,
container_inline_size: Au,
fragment_inline_size: Au,
fragment_block_size: Au) -> Au {
let style_inline_size = style.content_inline_size();
let style_block_size = style.content_block_size();
let style_min_inline_size = style.min_inline_size();
let style_max_inline_size = style.max_inline_size();
let style_min_block_size = style.min_block_size();
let style_max_block_size = style.max_block_size();
// TODO(ksh8281): compute border,margin
let inline_size = ReplacedImageFragmentInfo::style_length(
style_inline_size,
self.dom_inline_size,
container_inline_size);
let inline_size = match inline_size {
MaybeAuto::Auto => {
let intrinsic_width = fragment_inline_size;
let intrinsic_height = fragment_block_size;
if intrinsic_height == Au(0) {
intrinsic_width
} else {
let ratio = intrinsic_width.to_f32().unwrap() /
intrinsic_height.to_f32().unwrap();
let specified_height = ReplacedImageFragmentInfo::style_length(
style_block_size,
self.dom_block_size,
Au(0));
let specified_height = match specified_height {
MaybeAuto::Auto => intrinsic_height,
MaybeAuto::Specified(h) => h,
};
let specified_height = clamp_size(specified_height,
style_min_block_size,
style_max_block_size,
Au(0));
Au((specified_height.to_f32().unwrap() * ratio) as i32)
}
},
MaybeAuto::Specified(w) => w,
};
let inline_size = clamp_size(inline_size,
style_min_inline_size,
style_max_inline_size,
container_inline_size);
self.computed_inline_size = Some(inline_size);
inline_size + noncontent_inline_size
}
pub fn calculate_replaced_block_size(&mut self,
style: ComputedValues,
noncontent_block_size: Au,
containing_block_block_size: Au,
fragment_inline_size: Au,
fragment_block_size: Au) -> Au {
// TODO(ksh8281): compute border,margin,padding
let style_block_size = style.content_block_size();
let style_min_block_size = style.min_block_size();
let style_max_block_size = style.max_block_size();
let inline_size = self.computed_inline_size();
let block_size = ReplacedImageFragmentInfo::style_length(
style_block_size,
self.dom_block_size,
containing_block_block_size);
let block_size = match block_size {
MaybeAuto::Auto => {
let intrinsic_width = fragment_inline_size;
let intrinsic_height = fragment_block_size;
let scale = intrinsic_width.to_f32().unwrap() / inline_size.to_f32().unwrap();
Au((intrinsic_height.to_f32().unwrap() / scale) as i32)
},
MaybeAuto::Specified(h) => {
h
}
};
let block_size = clamp_size(block_size,
style_min_block_size,
style_max_block_size,
Au(0));
self.computed_block_size = Some(block_size);
block_size + noncontent_block_size
}
}
/// A fragment that represents an inline frame (iframe). This stores the pipeline ID so that the size
/// of this iframe can be communicated via the constellation to the iframe's own layout task.
#[derive(Clone)]
pub struct IframeFragmentInfo {
/// The pipeline ID of this iframe.
pub pipeline_id: PipelineId,
/// The subpage ID of this iframe.
pub subpage_id: SubpageId,
}
impl IframeFragmentInfo {
/// Creates the information specific to an iframe fragment.
pub fn new(node: &ThreadSafeLayoutNode) -> IframeFragmentInfo {
let (pipeline_id, subpage_id) = node.iframe_pipeline_and_subpage_ids();
IframeFragmentInfo {
pipeline_id: pipeline_id,
subpage_id: subpage_id,
}
}
#[inline]
pub fn calculate_replaced_inline_size(style: ComputedValues, containing_size: Au) -> Au {
// Calculate the replaced inline size (or default) as per CSS 2.1 § 10.3.2
IframeFragmentInfo::calculate_replaced_size(style.content_inline_size(),
style.min_inline_size(),
style.max_inline_size(),
containing_size,
Au::from_px(300))
}
#[inline]
pub fn calculate_replaced_block_size(style: ComputedValues, containing_size: Au) -> Au {
// Calculate the replaced block size (or default) as per CSS 2.1 § 10.3.2
IframeFragmentInfo::calculate_replaced_size(style.content_block_size(),
style.min_block_size(),
style.max_block_size(),
containing_size,
Au::from_px(150))
}
fn calculate_replaced_size(content_size: LengthOrPercentageOrAuto,
style_min_size: LengthOrPercentage,
style_max_size: LengthOrPercentageOrNone,
containing_size: Au, default_size: Au) -> Au {
let computed_size = match MaybeAuto::from_style(content_size, containing_size) {
MaybeAuto::Specified(length) => length,
MaybeAuto::Auto => default_size,
};
let size = clamp_size(computed_size,
style_min_size,
style_max_size,
containing_size);
size
}
}
/// A scanned text fragment represents a single run of text with a distinct style. A `TextFragment`
/// may be split into two or more fragments across line breaks. Several `TextFragment`s may
/// correspond to a single DOM text node. Split text fragments are implemented by referring to
/// subsets of a single `TextRun` object.
#[derive(Clone)]
pub struct ScannedTextFragmentInfo {
/// The text run that this represents.
pub run: Arc<Box<TextRun>>,
/// The range within the above text run that this represents.
pub range: Range<CharIndex>,
/// The positions of newlines within this scanned text fragment.
///
/// FIXME(#2260, pcwalton): Can't this go somewhere else, like in the text run or something?
/// Or can we just remove it?
pub new_line_pos: Vec<CharIndex>,
/// The new_line_pos is eaten during line breaking. If we need to re-merge
/// fragments, it will have to be restored.
pub original_new_line_pos: Option<Vec<CharIndex>>,
/// The intrinsic size of the text fragment.
pub content_size: LogicalSize<Au>,
}
impl ScannedTextFragmentInfo {
/// Creates the information specific to a scanned text fragment from a range and a text run.
pub fn new(run: Arc<Box<TextRun>>,
range: Range<CharIndex>,
new_line_positions: Vec<CharIndex>,
content_size: LogicalSize<Au>)
-> ScannedTextFragmentInfo {
ScannedTextFragmentInfo {
run: run,
range: range,
new_line_pos: new_line_positions,
original_new_line_pos: None,
content_size: content_size,
}
}
}
/// Describes how to split a fragment. This is used during line breaking as part of the return
/// value of `find_split_info_for_inline_size()`.
#[derive(Debug, Clone)]
pub struct SplitInfo {
// TODO(bjz): this should only need to be a single character index, but both values are
// currently needed for splitting in the `inline::try_append_*` functions.
pub range: Range<CharIndex>,
pub inline_size: Au,
}
impl SplitInfo {
fn new(range: Range<CharIndex>, info: &ScannedTextFragmentInfo) -> SplitInfo {
let inline_size = info.run.advance_for_range(&range);
SplitInfo {
range: range,
inline_size: inline_size,
}
}
}
/// Describes how to split a fragment into two. This contains up to two `SplitInfo`s.
pub struct SplitResult {
/// The part of the fragment that goes on the first line.
pub inline_start: Option<SplitInfo>,
/// The part of the fragment that goes on the second line.
pub inline_end: Option<SplitInfo>,
/// The text run which is being split.
pub text_run: Arc<Box<TextRun>>,
}
/// Describes how a fragment should be truncated.
pub struct TruncationResult {
/// The part of the fragment remaining after truncation.
pub split: SplitInfo,
/// The text run which is being truncated.
pub text_run: Arc<Box<TextRun>>,
}
/// Data for an unscanned text fragment. Unscanned text fragments are the results of flow
/// construction that have not yet had their inline-size determined.
#[derive(Clone)]
pub struct UnscannedTextFragmentInfo {
/// The text inside the fragment.
///
/// FIXME(pcwalton): Is there something more clever we can do here that avoids the double
/// indirection while not penalizing all fragments?
pub text: Box<String>,
}
impl UnscannedTextFragmentInfo {
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given DOM node.
pub fn new(node: &ThreadSafeLayoutNode) -> UnscannedTextFragmentInfo {
// FIXME(pcwalton): Don't copy text; atomically reference count it instead.
UnscannedTextFragmentInfo {
text: box node.text(),
}
}
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given text.
#[inline]
pub fn from_text(text: String) -> UnscannedTextFragmentInfo {
UnscannedTextFragmentInfo {
text: box text,
}
}
}
/// A fragment that represents a table column.
#[derive(Copy, Clone)]
pub struct TableColumnFragmentInfo {
/// the number of columns a <col> element should span
pub span: int,
}
impl TableColumnFragmentInfo {
/// Create the information specific to an table column fragment.
pub fn new(node: &ThreadSafeLayoutNode) -> TableColumnFragmentInfo {
let span = {
let element = node.as_element();
element.get_attr(&ns!(""), &atom!("span")).and_then(|string| {
let n: Option<int> = FromStr::from_str(string).ok();
n
}).unwrap_or(0)
};
TableColumnFragmentInfo {
span: span,
}
}
}
impl Fragment {
/// Constructs a new `Fragment` instance for the given node.
///
/// This does *not* construct the text for generated content. See comments in
/// `FlowConstructor::build_specific_fragment_info_for_node()` for more details.
///
/// Arguments:
///
/// * `constructor`: The flow constructor.
/// * `node`: The node to create a fragment for.
pub fn new(constructor: &mut FlowConstructor, node: &ThreadSafeLayoutNode) -> Fragment {
let style = node.style().clone();
let writing_mode = style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: style,
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: constructor.build_specific_fragment_info_for_node(node),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance from a specific info.
pub fn new_from_specific_info(node: &ThreadSafeLayoutNode, specific: SpecificFragmentInfo)
-> Fragment {
let style = node.style().clone();
let writing_mode = style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: style,
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance for an anonymous object.
pub fn new_anonymous(constructor: &mut FlowConstructor, node: &ThreadSafeLayoutNode)
-> Fragment {
let node_style = cascade_anonymous(&**node.style());
let writing_mode = node_style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: Arc::new(node_style),
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: constructor.build_specific_fragment_info_for_node(node),
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance for an anonymous table object.
pub fn new_anonymous_from_specific_info(node: &ThreadSafeLayoutNode,
specific: SpecificFragmentInfo)
-> Fragment {
// CSS 2.1 § 17.2.1 This is for non-inherited properties on anonymous table fragments
// example:
//
// <div style="display: table">
// Foo
// </div>
//
// Anonymous table fragments, SpecificFragmentInfo::TableRow and
// SpecificFragmentInfo::TableCell, are generated around `Foo`, but they shouldn't inherit
// the border.
let node_style = cascade_anonymous(&**node.style());
let writing_mode = node_style.writing_mode;
Fragment {
node: OpaqueNodeMethods::from_thread_safe_layout_node(node),
style: Arc::new(node_style),
restyle_damage: node.restyle_damage(),
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
/// Constructs a new `Fragment` instance from an opaque node.
pub fn from_opaque_node_and_style(node: OpaqueNode,
style: Arc<ComputedValues>,
restyle_damage: RestyleDamage,
specific: SpecificFragmentInfo)
-> Fragment {
let writing_mode = style.writing_mode;
Fragment {
node: node,
style: style,
restyle_damage: restyle_damage,
border_box: LogicalRect::zero(writing_mode),
border_padding: LogicalMargin::zero(writing_mode),
margin: LogicalMargin::zero(writing_mode),
specific: specific,
inline_context: None,
debug_id: layout_debug::generate_unique_debug_id(),
}
}
pub fn reset_inline_sizes(&mut self) {
self.border_padding = LogicalMargin::zero(self.style.writing_mode);
self.margin = LogicalMargin::zero(self.style.writing_mode);
}
/// Saves the new_line_pos vector into a `SpecificFragmentInfo::ScannedText`. This will fail
/// if called on any other type of fragment.
pub fn save_new_line_pos(&mut self) {
match &mut self.specific {
&mut SpecificFragmentInfo::ScannedText(ref mut info) => {
if !info.new_line_pos.is_empty() {
info.original_new_line_pos = Some(info.new_line_pos.clone());
}
}
_ => {}
}
}
pub fn restore_new_line_pos(&mut self) {
match &mut self.specific {
&mut SpecificFragmentInfo::ScannedText(ref mut info) => {
match info.original_new_line_pos.take() {
None => {}
Some(new_line_pos) => info.new_line_pos = new_line_pos,
}
return
}
_ => {}
}
}
/// Returns a debug ID of this fragment. This ID should not be considered stable across
/// multiple layouts or fragment manipulations.
pub fn debug_id(&self) -> u16 {
self.debug_id
}
/// Transforms this fragment into another fragment of the given type, with the given size,
/// preserving all the other data.
pub fn transform(&self, size: LogicalSize<Au>, info: SpecificFragmentInfo)
-> Fragment {
let new_border_box = LogicalRect::from_point_size(self.style.writing_mode,
self.border_box.start,
size);
Fragment {
node: self.node,
style: self.style.clone(),
restyle_damage: RestyleDamage::all(),
border_box: new_border_box,
border_padding: self.border_padding,
margin: self.margin,
specific: info,
inline_context: self.inline_context.clone(),
debug_id: self.debug_id,
}
}
/// Transforms this fragment using the given `SplitInfo`, preserving all the other data.
pub fn transform_with_split_info(&self,
split: &SplitInfo,
text_run: Arc<Box<TextRun>>)
-> Fragment {
let size = LogicalSize::new(self.style.writing_mode,
split.inline_size,
self.border_box.size.block);
let info = box ScannedTextFragmentInfo::new(text_run, split.range, Vec::new(), size);
self.transform(size, SpecificFragmentInfo::ScannedText(info))
}
/// Transforms this fragment into an ellipsis fragment, preserving all the other data.
pub fn transform_into_ellipsis(&self, layout_context: &LayoutContext) -> Fragment {
let mut unscanned_ellipsis_fragments = DList::new();
unscanned_ellipsis_fragments.push_back(self.transform(
self.border_box.size,
SpecificFragmentInfo::UnscannedText(UnscannedTextFragmentInfo::from_text(
"…".to_owned()))));
let ellipsis_fragments = TextRunScanner::new().scan_for_runs(layout_context.font_context(),
unscanned_ellipsis_fragments);
debug_assert!(ellipsis_fragments.len() == 1);
ellipsis_fragments.fragments.into_iter().next().unwrap()
}
pub fn restyle_damage(&self) -> RestyleDamage {
self.restyle_damage | self.specific.restyle_damage()
}
/// Adds a style to the inline context for this fragment. If the inline
/// context doesn't exist yet, it will be created.
pub fn add_inline_context_style(&mut self, style: Arc<ComputedValues>) {
if self.inline_context.is_none() {
self.inline_context = Some(InlineFragmentContext::new());
}
self.inline_context.as_mut().unwrap().styles.push(style.clone());
}
/// Determines which quantities (border/padding/margin/specified) should be included in the
/// intrinsic inline size of this fragment.
fn quantities_included_in_intrinsic_inline_size(&self)
-> QuantitiesIncludedInIntrinsicInlineSizes {
match self.specific {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::InlineBlock(_) => {
QuantitiesIncludedInIntrinsicInlineSizes::all()
}
SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell => {
INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
INTRINSIC_INLINE_SIZE_INCLUDES_BORDER |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED
}
SpecificFragmentInfo::TableWrapper => {
INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS |
INTRINSIC_INLINE_SIZE_INCLUDES_BORDER |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED
}
SpecificFragmentInfo::TableRow => {
INTRINSIC_INLINE_SIZE_INCLUDES_BORDER |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED
}
SpecificFragmentInfo::ScannedText(_) | SpecificFragmentInfo::TableColumn(_) | SpecificFragmentInfo::UnscannedText(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
QuantitiesIncludedInIntrinsicInlineSizes::empty()
}
}
}
/// Returns the portion of the intrinsic inline-size that consists of borders, padding, and/or
/// margins.
///
/// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
pub fn surrounding_intrinsic_inline_size(&self) -> Au {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let margin = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS) {
let margin = style.logical_margin();
(MaybeAuto::from_style(margin.inline_start, Au(0)).specified_or_zero() +
MaybeAuto::from_style(margin.inline_end, Au(0)).specified_or_zero())
} else {
Au(0)
};
// FIXME(pcwalton): Percentages should be relative to any definite size per CSS-SIZING.
// This will likely need to be done by pushing down definite sizes during selector
// cascading.
let padding = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_PADDING) {
let padding = style.logical_padding();
(model::specified(padding.inline_start, Au(0)) +
model::specified(padding.inline_end, Au(0)))
} else {
Au(0)
};
let border = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_BORDER) {
self.border_width().inline_start_end()
} else {
Au(0)
};
margin + padding + border
}
/// Uses the style only to estimate the intrinsic inline-sizes. These may be modified for text
/// or replaced elements.
fn style_specified_intrinsic_inline_size(&self) -> IntrinsicISizesContribution {
let flags = self.quantities_included_in_intrinsic_inline_size();
let style = self.style();
let specified = if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED) {
MaybeAuto::from_style(style.content_inline_size(), Au(0)).specified_or_zero()
} else {
Au(0)
};
// FIXME(#2261, pcwalton): This won't work well for inlines: is this OK?
let surrounding_inline_size = self.surrounding_intrinsic_inline_size();
IntrinsicISizesContribution {
content_intrinsic_sizes: IntrinsicISizes {
minimum_inline_size: specified,
preferred_inline_size: specified,
},
surrounding_size: surrounding_inline_size,
}
}
pub fn calculate_line_height(&self, layout_context: &LayoutContext) -> Au {
let font_style = self.style.get_font_arc();
let font_metrics = text::font_metrics_for_style(layout_context.font_context(), font_style);
text::line_height_from_style(&*self.style, &font_metrics)
}
/// Returns the sum of the inline-sizes of all the borders of this fragment. Note that this
/// can be expensive to compute, so if possible use the `border_padding` field instead.
#[inline]
pub fn border_width(&self) -> LogicalMargin<Au> {
let style_border_width = match self.specific {
SpecificFragmentInfo::ScannedText(_) => LogicalMargin::zero(self.style.writing_mode),
_ => self.style().logical_border_width(),
};
match self.inline_context {
None => style_border_width,
Some(ref inline_fragment_context) => {
inline_fragment_context.styles.iter().fold(style_border_width,
|acc, style| acc + style.logical_border_width())
}
}
}
/// Computes the margins in the inline direction from the containing block inline-size and the
/// style. After this call, the inline direction of the `margin` field will be correct.
///
/// Do not use this method if the inline direction margins are to be computed some other way
/// (for example, via constraint solving for blocks).
pub fn compute_inline_direction_margins(&mut self, containing_block_inline_size: Au) {
match self.specific {
SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell | SpecificFragmentInfo::TableRow | SpecificFragmentInfo::TableColumn(_) => {
self.margin.inline_start = Au(0);
self.margin.inline_end = Au(0)
}
_ => {
let margin = self.style().logical_margin();
self.margin.inline_start =
MaybeAuto::from_style(margin.inline_start, containing_block_inline_size)
.specified_or_zero();
self.margin.inline_end =
MaybeAuto::from_style(margin.inline_end, containing_block_inline_size)
.specified_or_zero();
}
}
}
/// Computes the margins in the block direction from the containing block inline-size and the
/// style. After this call, the block direction of the `margin` field will be correct.
///
/// Do not use this method if the block direction margins are to be computed some other way
/// (for example, via constraint solving for absolutely-positioned flows).
pub fn compute_block_direction_margins(&mut self, containing_block_inline_size: Au) {
match self.specific {
SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell | SpecificFragmentInfo::TableRow | SpecificFragmentInfo::TableColumn(_) => {
self.margin.block_start = Au(0);
self.margin.block_end = Au(0)
}
_ => {
// NB: Percentages are relative to containing block inline-size (not block-size)
// per CSS 2.1.
let margin = self.style().logical_margin();
self.margin.block_start =
MaybeAuto::from_style(margin.block_start, containing_block_inline_size)
.specified_or_zero();
self.margin.block_end =
MaybeAuto::from_style(margin.block_end, containing_block_inline_size)
.specified_or_zero();
}
}
}
/// Computes the border and padding in both inline and block directions from the containing
/// block inline-size and the style. After this call, the `border_padding` field will be
/// correct.
pub fn compute_border_and_padding(&mut self, containing_block_inline_size: Au) {
// Compute border.
let border = self.border_width();
// Compute padding.
let padding = match self.specific {
SpecificFragmentInfo::TableColumn(_) | SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper => LogicalMargin::zero(self.style.writing_mode),
_ => {
let style_padding = match self.specific {
SpecificFragmentInfo::ScannedText(_) => LogicalMargin::zero(self.style.writing_mode),
_ => model::padding_from_style(self.style(), containing_block_inline_size),
};
match self.inline_context {
None => style_padding,
Some(ref inline_fragment_context) => {
inline_fragment_context.styles.iter().fold(style_padding,
|acc, style| acc + model::padding_from_style(&**style, Au(0)))
}
}
}
};
self.border_padding = border + padding;
}
// Return offset from original position because of `position: relative`.
pub fn relative_position(&self, containing_block_size: &LogicalSize<Au>) -> LogicalSize<Au> {
fn from_style(style: &ComputedValues, container_size: &LogicalSize<Au>)
-> LogicalSize<Au> {
let offsets = style.logical_position();
let offset_i = if offsets.inline_start != LengthOrPercentageOrAuto::Auto {
MaybeAuto::from_style(offsets.inline_start, container_size.inline).specified_or_zero()
} else {
-MaybeAuto::from_style(offsets.inline_end, container_size.inline).specified_or_zero()
};
let offset_b = if offsets.block_start != LengthOrPercentageOrAuto::Auto {
MaybeAuto::from_style(offsets.block_start, container_size.inline).specified_or_zero()
} else {
-MaybeAuto::from_style(offsets.block_end, container_size.inline).specified_or_zero()
};
LogicalSize::new(style.writing_mode, offset_i, offset_b)
}
// Go over the ancestor fragments and add all relative offsets (if any).
let mut rel_pos = if self.style().get_box().position == position::T::relative {
from_style(self.style(), containing_block_size)
} else {
LogicalSize::zero(self.style.writing_mode)
};
match self.inline_context {
None => {}
Some(ref inline_fragment_context) => {
for style in inline_fragment_context.styles.iter() {
if style.get_box().position == position::T::relative {
rel_pos = rel_pos + from_style(&**style, containing_block_size);
}
}
},
}
rel_pos
}
/// Always inline for SCCP.
///
/// FIXME(pcwalton): Just replace with the clear type from the style module for speed?
#[inline(always)]
pub fn clear(&self) -> Option<ClearType> {
let style = self.style();
match style.get_box().clear {
clear::T::none => None,
clear::T::left => Some(ClearType::Left),
clear::T::right => Some(ClearType::Right),
clear::T::both => Some(ClearType::Both),
}
}
#[inline(always)]
pub fn style<'a>(&'a self) -> &'a ComputedValues {
&*self.style
}
/// Returns the text alignment of the computed style of the nearest ancestor-or-self `Element`
/// node.
pub fn text_align(&self) -> text_align::T {
self.style().get_inheritedtext().text_align
}
pub fn vertical_align(&self) -> vertical_align::T {
self.style().get_box().vertical_align
}
pub fn white_space(&self) -> white_space::T {
self.style().get_inheritedtext().white_space
}
/// Returns the text decoration of this fragment, according to the style of the nearest ancestor
/// element.
///
/// NB: This may not be the actual text decoration, because of the override rules specified in
/// CSS 2.1 § 16.3.1. Unfortunately, computing this properly doesn't really fit into Servo's
/// model. Therefore, this is a best lower bound approximation, but the end result may actually
/// have the various decoration flags turned on afterward.
pub fn text_decoration(&self) -> text_decoration::T {
self.style().get_text().text_decoration
}
/// Returns the inline-start offset from margin edge to content edge.
///
/// FIXME(#2262, pcwalton): I think this method is pretty bogus, because it won't work for
/// inlines.
pub fn inline_start_offset(&self) -> Au {
match self.specific {
SpecificFragmentInfo::TableWrapper => self.margin.inline_start,
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow => self.border_padding.inline_start,
SpecificFragmentInfo::TableColumn(_) => Au(0),
_ => self.margin.inline_start + self.border_padding.inline_start,
}
}
/// Returns true if this element can be split. This is true for text fragments.
pub fn can_split(&self) -> bool {
self.is_scanned_text_fragment()
}
/// Returns the newline positions of this fragment, if it's a scanned text fragment.
pub fn newline_positions(&self) -> Option<&Vec<CharIndex>> {
match self.specific {
SpecificFragmentInfo::ScannedText(ref info) => Some(&info.new_line_pos),
_ => None,
}
}
/// Returns the newline positions of this fragment, if it's a scanned text fragment.
pub fn newline_positions_mut(&mut self) -> Option<&mut Vec<CharIndex>> {
match self.specific {
SpecificFragmentInfo::ScannedText(ref mut info) => Some(&mut info.new_line_pos),
_ => None,
}
}
/// Returns true if and only if this is a scanned text fragment.
pub fn is_scanned_text_fragment(&self) -> bool {
match self.specific {
SpecificFragmentInfo::ScannedText(..) => true,
_ => false,
}
}
/// Computes the intrinsic inline-sizes of this fragment.
pub fn compute_intrinsic_inline_sizes(&mut self) -> IntrinsicISizesContribution {
let mut result = self.style_specified_intrinsic_inline_size();
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {}
SpecificFragmentInfo::InlineBlock(ref mut info) => {
let block_flow = info.flow_ref.as_block();
result.union_block(&block_flow.base.intrinsic_inline_sizes)
}
SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
let image_inline_size = image_fragment_info.image_inline_size();
result.union_block(&IntrinsicISizes {
minimum_inline_size: image_inline_size,
preferred_inline_size: image_inline_size,
})
}
SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
let canvas_inline_size = canvas_fragment_info.canvas_inline_size();
result.union_block(&IntrinsicISizes {
minimum_inline_size: canvas_inline_size,
preferred_inline_size: canvas_inline_size,
})
}
SpecificFragmentInfo::ScannedText(ref text_fragment_info) => {
let range = &text_fragment_info.range;
let min_line_inline_size = text_fragment_info.run.min_width_for_range(range);
// See http://dev.w3.org/csswg/css-sizing/#max-content-inline-size.
// TODO: Account for soft wrap opportunities.
let max_line_inline_size = text_fragment_info.run
.metrics_for_range(range)
.advance_width;
result.union_block(&IntrinsicISizes {
minimum_inline_size: min_line_inline_size,
preferred_inline_size: max_line_inline_size,
})
}
SpecificFragmentInfo::UnscannedText(..) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
};
// Take borders and padding for parent inline fragments into account, if necessary.
if self.is_primary_fragment() {
match self.inline_context {
None => {}
Some(ref context) => {
for style in context.styles.iter() {
let border_width = style.logical_border_width().inline_start_end();
let padding_inline_size =
model::padding_from_style(&**style, Au(0)).inline_start_end();
result.surrounding_size = result.surrounding_size + border_width +
padding_inline_size;
}
}
}
}
result
}
/// TODO: What exactly does this function return? Why is it Au(0) for SpecificFragmentInfo::Generic?
pub fn content_inline_size(&self) -> Au {
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => Au(0),
SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
canvas_fragment_info.replaced_image_fragment_info.computed_inline_size()
}
SpecificFragmentInfo::Image(ref image_fragment_info) => {
image_fragment_info.replaced_image_fragment_info.computed_inline_size()
}
SpecificFragmentInfo::ScannedText(ref text_fragment_info) => {
let (range, run) = (&text_fragment_info.range, &text_fragment_info.run);
let text_bounds = run.metrics_for_range(range).bounding_box;
text_bounds.size.width
}
SpecificFragmentInfo::TableColumn(_) => {
panic!("Table column fragments do not have inline_size")
}
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
}
}
/// Returns, and computes, the block-size of this fragment.
pub fn content_block_size(&self, layout_context: &LayoutContext) -> Au {
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => Au(0),
SpecificFragmentInfo::Image(ref image_fragment_info) => {
image_fragment_info.replaced_image_fragment_info.computed_block_size()
}
SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
canvas_fragment_info.replaced_image_fragment_info.computed_block_size()
}
SpecificFragmentInfo::ScannedText(_) => {
// Compute the block-size based on the line-block-size and font size.
self.calculate_line_height(layout_context)
}
SpecificFragmentInfo::TableColumn(_) => {
panic!("Table column fragments do not have block_size")
}
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
}
}
/// Returns the dimensions of the content box.
///
/// This is marked `#[inline]` because it is frequently called when only one or two of the
/// values are needed and that will save computation.
#[inline]
pub fn content_box(&self) -> LogicalRect<Au> {
self.border_box - self.border_padding
}
/// Find the split of a fragment that includes a new-line character.
///
/// A return value of `None` indicates that the fragment is not splittable.
/// Otherwise the split information is returned. The right information is
/// optional due to the possibility of it being whitespace.
//
// TODO(bjz): The text run should be removed in the future, but it is currently needed for
// the current method of fragment splitting in the `inline::try_append_*` functions.
pub fn find_split_info_by_new_line(&self)
-> Option<(SplitInfo, Option<SplitInfo>, Arc<Box<TextRun>> /* TODO(bjz): remove */)> {
match self.specific {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper => {
None
}
SpecificFragmentInfo::TableColumn(_) => {
panic!("Table column fragments do not need to split")
}
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
panic!("Inline blocks or inline absolute hypothetical fragments do not get split")
}
SpecificFragmentInfo::ScannedText(ref text_fragment_info) => {
let mut new_line_pos = text_fragment_info.new_line_pos.clone();
let cur_new_line_pos = new_line_pos.remove(0);
let inline_start_range = Range::new(text_fragment_info.range.begin(),
cur_new_line_pos);
let inline_end_range = Range::new(
text_fragment_info.range.begin() + cur_new_line_pos + CharIndex(1),
text_fragment_info.range.length() - (cur_new_line_pos + CharIndex(1)));
// Left fragment is for inline-start text of first founded new-line character.
let inline_start_fragment = SplitInfo::new(inline_start_range,
&**text_fragment_info);
// Right fragment is for inline-end text of first founded new-line character.
let inline_end_fragment = if inline_end_range.length() > CharIndex(0) {
Some(SplitInfo::new(inline_end_range, &**text_fragment_info))
} else {
None
};
Some((inline_start_fragment, inline_end_fragment, text_fragment_info.run.clone()))
}
}
}
/// Attempts to find the split positions of a text fragment so that its inline-size is no more
/// than `max_inline_size`.
///
/// A return value of `None` indicates that the fragment could not be split. Otherwise the
/// information pertaining to the split is returned. The inline-start and inline-end split
/// information are both optional due to the possibility of them being whitespace.
pub fn calculate_split_position(&self, max_inline_size: Au, starts_line: bool)
-> Option<SplitResult> {
let text_fragment_info =
if let SpecificFragmentInfo::ScannedText(ref text_fragment_info) = self.specific {
text_fragment_info
} else {
return None
};
let mut flags = SplitOptions::empty();
if starts_line {
flags.insert(STARTS_LINE);
if self.style().get_inheritedtext().overflow_wrap == overflow_wrap::T::break_word {
flags.insert(RETRY_AT_CHARACTER_BOUNDARIES)
}
}
match self.style().get_inheritedtext().word_break {
word_break::T::normal => {
// Break at normal word boundaries.
let natural_word_breaking_strategy =
text_fragment_info.run.natural_word_slices_in_range(&text_fragment_info.range);
self.calculate_split_position_using_breaking_strategy(
natural_word_breaking_strategy,
max_inline_size,
flags)
}
word_break::T::break_all => {
// Break at character boundaries.
let character_breaking_strategy =
text_fragment_info.run.character_slices_in_range(&text_fragment_info.range);
flags.remove(RETRY_AT_CHARACTER_BOUNDARIES);
return self.calculate_split_position_using_breaking_strategy(
character_breaking_strategy,
max_inline_size,
flags)
}
}
}
/// Truncates this fragment to the given `max_inline_size`, using a character-based breaking
/// strategy. If no characters could fit, returns `None`.
pub fn truncate_to_inline_size(&self, max_inline_size: Au) -> Option<TruncationResult> {
let text_fragment_info =
if let SpecificFragmentInfo::ScannedText(ref text_fragment_info) = self.specific {
text_fragment_info
} else {
return None
};
let character_breaking_strategy =
text_fragment_info.run.character_slices_in_range(&text_fragment_info.range);
match self.calculate_split_position_using_breaking_strategy(character_breaking_strategy,
max_inline_size,
SplitOptions::empty()) {
None => None,
Some(split_info) => {
match split_info.inline_start {
None => None,
Some(split) => {
Some(TruncationResult {
split: split,
text_run: split_info.text_run.clone(),
})
}
}
}
}
}
/// A helper method that uses the breaking strategy described by `slice_iterator` (at present,
/// either natural word breaking or character breaking) to split this fragment.
fn calculate_split_position_using_breaking_strategy<'a,I>(&self,
mut slice_iterator: I,
max_inline_size: Au,
flags: SplitOptions)
-> Option<SplitResult>
where I: Iterator<Item=
TextRunSlice<'a>> {
let text_fragment_info =
if let SpecificFragmentInfo::ScannedText(ref text_fragment_info) = self.specific {
text_fragment_info
} else {
return None
};
let mut pieces_processed_count: uint = 0;
let mut remaining_inline_size = max_inline_size;
let mut inline_start_range = Range::new(text_fragment_info.range.begin(), CharIndex(0));
let mut inline_end_range = None;
let mut overflowing = false;
debug!("calculate_split_position: splitting text fragment (strlen={}, range={:?}, \
max_inline_size={:?})",
text_fragment_info.run.text.len(),
text_fragment_info.range,
max_inline_size);
for slice in slice_iterator {
debug!("calculate_split_position: considering slice (offset={:?}, slice range={:?}, \
remaining_inline_size={:?})",
slice.offset,
slice.range,
remaining_inline_size);
let metrics = text_fragment_info.run.metrics_for_slice(slice.glyphs, &slice.range);
let advance = metrics.advance_width;
// Have we found the split point?
if advance <= remaining_inline_size || slice.glyphs.is_whitespace() {
// Keep going; we haven't found the split point yet.
if flags.contains(STARTS_LINE) && pieces_processed_count == 0 &&
slice.glyphs.is_whitespace() {
debug!("calculate_split_position: skipping leading trimmable whitespace");
inline_start_range.shift_by(slice.range.length());
} else {
debug!("split_to_inline_size: enlarging span");
remaining_inline_size = remaining_inline_size - advance;
inline_start_range.extend_by(slice.range.length());
}
pieces_processed_count += 1;
continue
}
// The advance is more than the remaining inline-size, so split here. First, check to
// see if we're going to overflow the line. If so, perform a best-effort split.
let mut remaining_range = slice.text_run_range();
if inline_start_range.is_empty() {
// We're going to overflow the line.
overflowing = true;
inline_start_range = slice.text_run_range();
remaining_range = Range::new(slice.text_run_range().end(), CharIndex(0));
remaining_range.extend_to(text_fragment_info.range.end());
}
// Check to see if we need to create an inline-end chunk.
let slice_begin = remaining_range.begin();
if slice_begin < text_fragment_info.range.end() {
// There still some things left over at the end of the line, so create the
// inline-end chunk.
let mut inline_end = remaining_range;
inline_end.extend_to(text_fragment_info.range.end());
inline_end_range = Some(inline_end);
debug!("calculate_split_position: splitting remainder with inline-end range={:?}",
inline_end);
}
break
}
// If we failed to find a suitable split point, we're on the verge of overflowing the line.
if inline_start_range.is_empty() || overflowing {
// If we've been instructed to retry at character boundaries (probably via
// `overflow-wrap: break-word`), do so.
if flags.contains(RETRY_AT_CHARACTER_BOUNDARIES) {
let character_breaking_strategy =
text_fragment_info.run.character_slices_in_range(&text_fragment_info.range);
let mut flags = flags;
flags.remove(RETRY_AT_CHARACTER_BOUNDARIES);
return self.calculate_split_position_using_breaking_strategy(
character_breaking_strategy,
max_inline_size,
flags)
}
// We aren't at the start of the line, so don't overflow. Let inline layout wrap to the
// next line instead.
if !flags.contains(STARTS_LINE) {
return None
}
}
// Remove trailing whitespace from the inline-start split, if necessary.
//
// FIXME(pcwalton): Is there a more clever (i.e. faster) way to do this?
strip_trailing_whitespace(&**text_fragment_info.run, &mut inline_start_range);
// Remove leading whitespace from the inline-end split, if necessary.
//
// FIXME(pcwalton): Is there a more clever (i.e. faster) way to do this?
if let Some(ref mut inline_end_range) = inline_end_range {
let inline_end_fragment_text =
text_fragment_info.run.text.slice_chars(inline_end_range.begin().to_uint(),
inline_end_range.end().to_uint());
let mut leading_whitespace_character_count = 0i;
for ch in inline_end_fragment_text.chars() {
if ch.is_whitespace() {
leading_whitespace_character_count += 1
} else {
break
}
}
inline_end_range.adjust_by(CharIndex(leading_whitespace_character_count),
-CharIndex(leading_whitespace_character_count));
}
// Normalize our split so that the inline-end fragment will never be `Some` while the
// inline-start fragment is `None`.
if inline_start_range.is_empty() && inline_end_range.is_some() {
inline_start_range = inline_end_range.unwrap();
inline_end_range = None
}
let inline_start = if !inline_start_range.is_empty() {
Some(SplitInfo::new(inline_start_range, &**text_fragment_info))
} else {
None
};
let inline_end = inline_end_range.map(|inline_end_range| {
SplitInfo::new(inline_end_range, &**text_fragment_info)
});
Some(SplitResult {
inline_start: inline_start,
inline_end: inline_end,
text_run: text_fragment_info.run.clone(),
})
}
/// Attempts to strip trailing whitespace from this fragment by adjusting the text run range.
/// Returns true if any modifications were made.
pub fn strip_trailing_whitespace_if_necessary(&mut self) -> bool {
let text_fragment_info =
if let SpecificFragmentInfo::ScannedText(ref mut text_fragment_info) = self.specific {
text_fragment_info
} else {
return false
};
let run = text_fragment_info.run.clone();
if strip_trailing_whitespace(&**run, &mut text_fragment_info.range) {
self.border_box.size.inline = run.advance_for_range(&text_fragment_info.range);
return true
}
false
}
/// Returns true if this fragment is an unscanned text fragment that consists entirely of
/// whitespace that should be stripped.
pub fn is_ignorable_whitespace(&self) -> bool {
match self.white_space() {
white_space::T::pre => return false,
white_space::T::normal | white_space::T::nowrap => {}
}
match self.specific {
SpecificFragmentInfo::UnscannedText(ref text_fragment_info) => {
is_whitespace(text_fragment_info.text.as_slice())
}
_ => false,
}
}
/// Assigns replaced inline-size, padding, and margins for this fragment only if it is replaced
/// content per CSS 2.1 § 10.3.2.
pub fn assign_replaced_inline_size_if_necessary<'a>(&'a mut self, container_inline_size: Au) {
match self.specific {
SpecificFragmentInfo::Generic | SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow | SpecificFragmentInfo::TableWrapper => return,
SpecificFragmentInfo::TableColumn(_) => panic!("Table column fragments do not have inline_size"),
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
SpecificFragmentInfo::Canvas(_) | SpecificFragmentInfo::Image(_) | SpecificFragmentInfo::ScannedText(_) | SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) | SpecificFragmentInfo::Iframe(_) => {}
};
let style = self.style().clone();
let noncontent_inline_size = self.border_padding.inline_start_end();
match self.specific {
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
let block_flow = info.flow_ref.as_block();
block_flow.base.position.size.inline =
block_flow.base.intrinsic_inline_sizes.preferred_inline_size;
// This is a hypothetical box, so it takes up no space.
self.border_box.size.inline = Au(0);
}
SpecificFragmentInfo::InlineBlock(ref mut info) => {
let block_flow = info.flow_ref.as_block();
self.border_box.size.inline =
block_flow.base.intrinsic_inline_sizes.preferred_inline_size;
block_flow.base.block_container_inline_size = self.border_box.size.inline;
}
SpecificFragmentInfo::ScannedText(ref info) => {
// Scanned text fragments will have already had their content inline-sizes assigned
// by this point.
self.border_box.size.inline = info.content_size.inline + noncontent_inline_size
}
SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
let fragment_inline_size = image_fragment_info.image_inline_size();
let fragment_block_size = image_fragment_info.image_block_size();
self.border_box.size.inline = image_fragment_info.replaced_image_fragment_info.
calculate_replaced_inline_size(style,
noncontent_inline_size,
container_inline_size,
fragment_inline_size,
fragment_block_size);
}
SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
let fragment_inline_size = canvas_fragment_info.canvas_inline_size();
let fragment_block_size = canvas_fragment_info.canvas_block_size();
self.border_box.size.inline = canvas_fragment_info.replaced_image_fragment_info.
calculate_replaced_inline_size(style,
noncontent_inline_size,
container_inline_size,
fragment_inline_size,
fragment_block_size);
}
SpecificFragmentInfo::Iframe(_) => {
self.border_box.size.inline = IframeFragmentInfo::calculate_replaced_inline_size(
style, container_inline_size) +
noncontent_inline_size;
}
_ => panic!("this case should have been handled above"),
}
}
/// Assign block-size for this fragment if it is replaced content. The inline-size must have
/// been assigned first.
///
/// Ideally, this should follow CSS 2.1 § 10.6.2.
pub fn assign_replaced_block_size_if_necessary(&mut self, containing_block_block_size: Au) {
match self.specific {
SpecificFragmentInfo::Generic | SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow | SpecificFragmentInfo::TableWrapper => return,
SpecificFragmentInfo::TableColumn(_) => panic!("Table column fragments do not have block_size"),
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Unscanned text fragments should have been scanned by now!")
}
SpecificFragmentInfo::Canvas(_) | SpecificFragmentInfo::Image(_) | SpecificFragmentInfo::ScannedText(_) | SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) | SpecificFragmentInfo::Iframe(_) => {}
}
let style = self.style().clone();
let noncontent_block_size = self.border_padding.block_start_end();
match self.specific {
SpecificFragmentInfo::Image(ref mut image_fragment_info) => {
let fragment_inline_size = image_fragment_info.image_inline_size();
let fragment_block_size = image_fragment_info.image_block_size();
self.border_box.size.block = image_fragment_info.replaced_image_fragment_info.
calculate_replaced_block_size(style,
noncontent_block_size,
containing_block_block_size,
fragment_inline_size,
fragment_block_size);
}
SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
let fragment_inline_size = canvas_fragment_info.canvas_inline_size();
let fragment_block_size = canvas_fragment_info.canvas_block_size();
self.border_box.size.block = canvas_fragment_info.replaced_image_fragment_info.
calculate_replaced_block_size(style,
noncontent_block_size,
containing_block_block_size,
fragment_inline_size,
fragment_block_size);
}
SpecificFragmentInfo::ScannedText(ref info) => {
// Scanned text fragments' content block-sizes are calculated by the text run
// scanner during flow construction.
self.border_box.size.block = info.content_size.block + noncontent_block_size
}
SpecificFragmentInfo::InlineBlock(ref mut info) => {
// Not the primary fragment, so we do not take the noncontent size into account.
let block_flow = info.flow_ref.as_block();
self.border_box.size.block = block_flow.base.position.size.block +
block_flow.fragment.margin.block_start_end()
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
// Not the primary fragment, so we do not take the noncontent size into account.
let block_flow = info.flow_ref.as_block();
self.border_box.size.block = block_flow.base.position.size.block;
}
SpecificFragmentInfo::Iframe(_) => {
self.border_box.size.block = IframeFragmentInfo::calculate_replaced_block_size(
style, containing_block_block_size) +
noncontent_block_size;
}
_ => panic!("should have been handled above"),
}
}
/// Calculates block-size above baseline, depth below baseline, and ascent for this fragment when
/// used in an inline formatting context. See CSS 2.1 § 10.8.1.
pub fn inline_metrics(&self, layout_context: &LayoutContext) -> InlineMetrics {
match self.specific {
SpecificFragmentInfo::Image(ref image_fragment_info) => {
let computed_block_size = image_fragment_info.replaced_image_fragment_info.computed_block_size();
InlineMetrics {
block_size_above_baseline: computed_block_size + self.border_padding.block_start_end(),
depth_below_baseline: Au(0),
ascent: computed_block_size + self.border_padding.block_end,
}
}
SpecificFragmentInfo::ScannedText(ref text_fragment) => {
// See CSS 2.1 § 10.8.1.
let line_height = self.calculate_line_height(layout_context);
InlineMetrics::from_font_metrics(&text_fragment.run.font_metrics, line_height)
}
SpecificFragmentInfo::InlineBlock(ref info) => {
// See CSS 2.1 § 10.8.1.
let block_flow = info.flow_ref.as_immutable_block();
let font_style = self.style.get_font_arc();
let font_metrics = text::font_metrics_for_style(layout_context.font_context(),
font_style);
InlineMetrics::from_block_height(&font_metrics,
block_flow.base.position.size.block +
block_flow.fragment.margin.block_start_end())
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
// Hypothetical boxes take up no space.
InlineMetrics {
block_size_above_baseline: Au(0),
depth_below_baseline: Au(0),
ascent: Au(0),
}
}
_ => {
InlineMetrics {
block_size_above_baseline: self.border_box.size.block,
depth_below_baseline: Au(0),
ascent: self.border_box.size.block,
}
}
}
}
/// Returns true if this fragment is a hypothetical box. See CSS 2.1 § 10.3.7.
pub fn is_hypothetical(&self) -> bool {
match self.specific {
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => true,
_ => false,
}
}
/// Returns true if this fragment can merge with another adjacent fragment or false otherwise.
pub fn can_merge_with_fragment(&self, other: &Fragment) -> bool {
match (&self.specific, &other.specific) {
(&SpecificFragmentInfo::UnscannedText(_), &SpecificFragmentInfo::UnscannedText(_)) => {
// FIXME: Should probably use a whitelist of styles that can safely differ (#3165)
self.style().get_font() == other.style().get_font() &&
self.text_decoration() == other.text_decoration() &&
self.white_space() == other.white_space()
}
_ => false,
}
}
/// Returns true if and only if this is the *primary fragment* for the fragment's style object
/// (conceptually, though style sharing makes this not really true, of course). The primary
/// fragment is the one that draws backgrounds, borders, etc., and takes borders, padding and
/// margins into account. Every style object has at most one primary fragment.
///
/// At present, all fragments are primary fragments except for inline-block and table wrapper
/// fragments. Inline-block fragments are not primary fragments because the corresponding block
/// flow is the primary fragment, while table wrapper fragments are not primary fragments
/// because the corresponding table flow is the primary fragment.
pub fn is_primary_fragment(&self) -> bool {
match self.specific {
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::TableWrapper => false,
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::UnscannedText(_) => true,
}
}
pub fn update_late_computed_inline_position_if_necessary(&mut self) {
match self.specific {
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
let position = self.border_box.start.i;
info.flow_ref.update_late_computed_inline_position_if_necessary(position)
}
_ => {}
}
}
pub fn update_late_computed_block_position_if_necessary(&mut self) {
match self.specific {
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
let position = self.border_box.start.b;
info.flow_ref.update_late_computed_block_position_if_necessary(position)
}
_ => {}
}
}
pub fn repair_style(&mut self, new_style: &Arc<ComputedValues>) {
self.style = (*new_style).clone()
}
/// Given the stacking-context-relative position of the containing flow, returns the border box
/// of this fragment relative to the parent stacking context. This takes `position: relative`
/// into account.
///
/// If `coordinate_system` is `Parent`, this returns the border box in the parent stacking
/// context's coordinate system. Otherwise, if `coordinate_system` is `Self` and this fragment
/// establishes a stacking context itself, this returns a border box anchored at (0, 0). (If
/// this fragment does not establish a stacking context, then it always belongs to its parent
/// stacking context and thus `coordinate_system` is ignored.)
///
/// This is the method you should use for display list construction as well as
/// `getBoundingClientRect()` and so forth.
pub fn stacking_relative_border_box(&self,
stacking_relative_flow_origin: &Point2D<Au>,
relative_containing_block_size: &LogicalSize<Au>,
coordinate_system: CoordinateSystem)
-> Rect<Au> {
// FIXME(pcwalton, #2795): Get the real container size.
let container_size = Size2D::zero();
let border_box = self.border_box.to_physical(self.style.writing_mode, container_size);
if coordinate_system == CoordinateSystem::Self && self.establishes_stacking_context() {
return Rect(ZERO_POINT, border_box.size)
}
// FIXME(pcwalton): This can double-count relative position sometimes for inlines (e.g.
// `<div style="position:relative">x</div>`, because the `position:relative` trickles down
// to the inline flow. Possibly we should extend the notion of "primary fragment" to fix
// this.
let relative_position = self.relative_position(relative_containing_block_size);
border_box.translate_by_size(&relative_position.to_physical(self.style.writing_mode))
.translate(stacking_relative_flow_origin)
}
/// Given the stacking-context-relative border box, returns the stacking-context-relative
/// content box.
pub fn stacking_relative_content_box(&self, stacking_relative_border_box: &Rect<Au>)
-> Rect<Au> {
let border_padding = self.border_padding.to_physical(self.style.writing_mode);
Rect(Point2D(stacking_relative_border_box.origin.x + border_padding.left,
stacking_relative_border_box.origin.y + border_padding.top),
Size2D(stacking_relative_border_box.size.width - border_padding.horizontal(),
stacking_relative_border_box.size.height - border_padding.vertical()))
}
/// Returns true if this fragment establishes a new stacking context and false otherwise.
pub fn establishes_stacking_context(&self) -> bool {
if self.style().get_effects().opacity != 1.0 {
return true
}
if !self.style().get_effects().filter.is_empty() {
return true
}
if self.style().get_effects().mix_blend_mode != mix_blend_mode::T::normal {
return true
}
match self.style().get_box().position {
position::T::absolute | position::T::fixed => {
// FIXME(pcwalton): This should only establish a new stacking context when
// `z-index` is not `auto`. But this matches what we did before.
true
}
position::T::relative | position::T::static_ => {
// FIXME(pcwalton): `position: relative` establishes a new stacking context if
// `z-index` is not `auto`. But this matches what we did before.
false
}
}
}
/// Computes the overflow rect of this fragment relative to the start of the flow.
pub fn compute_overflow(&self) -> Rect<Au> {
// FIXME(pcwalton, #2795): Get the real container size.
let container_size = Size2D::zero();
let mut border_box = self.border_box.to_physical(self.style.writing_mode, container_size);
// Relative position can cause us to draw outside our border box.
//
// FIXME(pcwalton): I'm not a fan of the way this makes us crawl though so many styles all
// the time. Can't we handle relative positioning by just adjusting `border_box`?
let relative_position =
self.relative_position(&LogicalSize::zero(self.style.writing_mode));
border_box =
border_box.translate_by_size(&relative_position.to_physical(self.style.writing_mode));
let mut overflow = border_box;
// Box shadows cause us to draw outside our border box.
for box_shadow in self.style().get_effects().box_shadow.iter() {
let offset = Point2D(box_shadow.offset_x, box_shadow.offset_y);
let inflation = box_shadow.spread_radius +
box_shadow.blur_radius * BOX_SHADOW_INFLATION_FACTOR;
overflow = overflow.union(&border_box.translate(&offset).inflate(inflation, inflation))
}
// Outlines cause us to draw outside our border box.
let outline_width = self.style.get_outline().outline_width;
if outline_width != Au(0) {
overflow = overflow.union(&border_box.inflate(outline_width, outline_width))
}
// FIXME(pcwalton): Sometimes excessively fancy glyphs can make us draw outside our border
// box too.
overflow
}
}
impl fmt::Debug for Fragment {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(write!(f, "({} {} ", self.debug_id(), self.specific.get_type()));
try!(write!(f, "bp {:?}", self.border_padding));
try!(write!(f, " "));
try!(write!(f, "m {:?}", self.margin));
write!(f, ")")
}
}
bitflags! {
flags QuantitiesIncludedInIntrinsicInlineSizes: u8 {
const INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS = 0x01,
const INTRINSIC_INLINE_SIZE_INCLUDES_PADDING = 0x02,
const INTRINSIC_INLINE_SIZE_INCLUDES_BORDER = 0x04,
const INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED = 0x08,
}
}
bitflags! {
// Various flags we can use when splitting fragments. See
// `calculate_split_position_using_breaking_strategy()`.
flags SplitOptions: u8 {
#[doc="True if this is the first fragment on the line."]
const STARTS_LINE = 0x01,
#[doc="True if we should attempt to split at character boundaries if this split fails. \
This is used to implement `overflow-wrap: break-word`."]
const RETRY_AT_CHARACTER_BOUNDARIES = 0x02
}
}
/// A top-down fragment border box iteration handler.
pub trait FragmentBorderBoxIterator {
/// The operation to perform.
fn process(&mut self, fragment: &Fragment, overflow: &Rect<Au>);
/// Returns true if this fragment must be processed in-order. If this returns false,
/// we skip the operation for this fragment, but continue processing siblings.
fn should_process(&mut self, fragment: &Fragment) -> bool;
}
/// The coordinate system used in `stacking_relative_border_box()`. See the documentation of that
/// method for details.
#[derive(Clone, PartialEq, Debug)]
pub enum CoordinateSystem {
/// The border box returned is relative to the fragment's parent stacking context.
Parent,
/// The border box returned is relative to the fragment's own stacking context, if applicable.
Self,
}
/// Given a range and a text run, adjusts the range to eliminate trailing whitespace. Returns true
/// if any modifications were made.
fn strip_trailing_whitespace(text_run: &TextRun, range: &mut Range<CharIndex>) -> bool {
// FIXME(pcwalton): Is there a more clever (i.e. faster) way to do this?
let text = text_run.text.slice_chars(range.begin().to_uint(), range.end().to_uint());
let mut trailing_whitespace_character_count = 0i;
for ch in text.chars().rev() {
if ch.is_whitespace() {
trailing_whitespace_character_count += 1
} else {
break
}
}
if trailing_whitespace_character_count == 0 {
return false
}
range.extend_by(-CharIndex(trailing_whitespace_character_count));
return true
}
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