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servo/components/layout/fragment.rs
kilobtye 0a86543e6d Let textarea wrap lines
2016-07-26 20:38:11 +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_code)]
use app_units::Au;
use canvas_traits::CanvasMsg;
use context::LayoutContext;
use euclid::{Point2D, Rect, Size2D};
use floats::ClearType;
use flow::{self, ImmutableFlowUtils};
use flow_ref::{self, FlowRef};
use gfx;
use gfx::display_list::{BLUR_INFLATION_FACTOR, OpaqueNode};
use gfx::text::glyph::ByteIndex;
use gfx::text::text_run::{TextRun, TextRunSlice};
use gfx_traits::{FragmentType, LayerId, LayerType, StackingContextId};
use inline::{FIRST_FRAGMENT_OF_ELEMENT, InlineFragmentContext, InlineFragmentNodeInfo};
use inline::{InlineMetrics, LAST_FRAGMENT_OF_ELEMENT};
use ipc_channel::ipc::IpcSender;
#[cfg(debug_assertions)]
use layout_debug;
use model::{self, IntrinsicISizes, IntrinsicISizesContribution, MaybeAuto, specified};
use msg::constellation_msg::PipelineId;
use net_traits::image::base::{Image, ImageMetadata};
use net_traits::image_cache_thread::{ImageOrMetadataAvailable, UsePlaceholder};
use range::*;
use rustc_serialize::{Encodable, Encoder};
use script_layout_interface::HTMLCanvasData;
use script_layout_interface::restyle_damage::{RECONSTRUCT_FLOW, RestyleDamage};
use script_layout_interface::wrapper_traits::{PseudoElementType, ThreadSafeLayoutElement, ThreadSafeLayoutNode};
use std::borrow::ToOwned;
use std::cmp::{max, min};
use std::collections::LinkedList;
use std::fmt;
use std::sync::{Arc, Mutex};
use style::computed_values::content::ContentItem;
use style::computed_values::{border_collapse, clear, color, display, mix_blend_mode};
use style::computed_values::{overflow_wrap, overflow_x, position, text_decoration};
use style::computed_values::{transform_style, vertical_align, white_space, word_break, z_index};
use style::dom::TRestyleDamage;
use style::logical_geometry::{LogicalMargin, LogicalRect, LogicalSize, WritingMode};
use style::properties::{ComputedValues, ServoComputedValues};
use style::str::char_is_whitespace;
use style::values::computed::LengthOrPercentageOrNone;
use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
use text;
use text::TextRunScanner;
use url::Url;
use util;
/// 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<ServoComputedValues>,
/// The CSS style of this fragment when it's selected
pub selected_style: Arc<ServoComputedValues>,
/// 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.
/// NB: Collapsed borders are not included in this.
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>,
/// How damaged this fragment is since last reflow.
pub restyle_damage: RestyleDamage,
/// The pseudo-element that this fragment represents.
pub pseudo: PseudoElementType<()>,
/// Various flags for this fragment.
pub flags: FragmentFlags,
/// A debug ID that is consistent for the life of this fragment (via transform etc).
/// This ID should not be considered stable across multiple layouts or fragment
/// manipulations.
debug_id: DebugId,
/// The ID of the StackingContext that contains this fragment. This is initialized
/// to 0, but it assigned during the collect_stacking_contexts phase of display
/// list construction.
pub stacking_context_id: StackingContextId,
}
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,
/// A piece of generated content that cannot be resolved into `ScannedText` until the generated
/// content resolution phase (e.g. an ordered list item marker).
GeneratedContent(Box<GeneratedContentInfo>),
Iframe(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),
/// An inline fragment that establishes an absolute containing block for its descendants (i.e.
/// a positioned inline fragment).
InlineAbsolute(InlineAbsoluteFragmentInfo),
ScannedText(Box<ScannedTextFragmentInfo>),
Table,
TableCell,
TableColumn(TableColumnFragmentInfo),
TableRow,
TableWrapper,
Multicol,
MulticolColumn,
UnscannedText(Box<UnscannedTextFragmentInfo>),
}
impl SpecificFragmentInfo {
fn restyle_damage(&self) -> RestyleDamage {
let flow =
match *self {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::UnscannedText(_) |
SpecificFragmentInfo::Generic => return RestyleDamage::empty(),
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref info) => &info.flow_ref,
SpecificFragmentInfo::InlineAbsolute(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::GeneratedContent(_) => "SpecificFragmentInfo::GeneratedContent",
SpecificFragmentInfo::Iframe(_) => "SpecificFragmentInfo::Iframe",
SpecificFragmentInfo::Image(_) => "SpecificFragmentInfo::Image",
SpecificFragmentInfo::InlineAbsolute(_) => "SpecificFragmentInfo::InlineAbsolute",
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::Multicol => "SpecificFragmentInfo::Multicol",
SpecificFragmentInfo::MulticolColumn => "SpecificFragmentInfo::MulticolColumn",
SpecificFragmentInfo::UnscannedText(_) => "SpecificFragmentInfo::UnscannedText",
}
}
}
impl fmt::Debug for SpecificFragmentInfo {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
SpecificFragmentInfo::ScannedText(ref info) => write!(f, "{:?}", info.text()),
SpecificFragmentInfo::UnscannedText(ref info) => write!(f, "{:?}", info.text),
_ => Ok(())
}
}
}
/// Clamp a value obtained from style_length, based on min / max lengths.
fn clamp_size(size: Au,
min_size: LengthOrPercentage,
max_size: LengthOrPercentageOrNone,
container_size: Au)
-> Au {
let min_size = model::specified(min_size, container_size);
let max_size = model::specified_or_none(max_size, container_size);
max(min_size, match max_size {
None => size,
Some(max_size) => min(size, max_size),
})
}
/// Information for generated content.
#[derive(Clone)]
pub enum GeneratedContentInfo {
ListItem,
ContentItem(ContentItem),
/// Placeholder for elements with generated content that did not generate any fragments.
Empty,
}
/// 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,
}
}
}
/// An inline fragment that establishes an absolute containing block for its descendants (i.e.
/// a positioned inline fragment).
///
/// FIXME(pcwalton): Stop leaking this `FlowRef` to layout; that is not memory safe because layout
/// can clone it.
#[derive(Clone)]
pub struct InlineAbsoluteFragmentInfo {
pub flow_ref: FlowRef,
}
impl InlineAbsoluteFragmentInfo {
pub fn new(flow_ref: FlowRef) -> InlineAbsoluteFragmentInfo {
InlineAbsoluteFragmentInfo {
flow_ref: flow_ref,
}
}
}
#[derive(Clone)]
pub struct CanvasFragmentInfo {
pub replaced_image_fragment_info: ReplacedImageFragmentInfo,
pub ipc_renderer: Option<Arc<Mutex<IpcSender<CanvasMsg>>>>,
pub dom_width: Au,
pub dom_height: Au,
}
impl CanvasFragmentInfo {
pub fn new<N: ThreadSafeLayoutNode>(node: &N, data: HTMLCanvasData, ctx: &LayoutContext) -> CanvasFragmentInfo {
CanvasFragmentInfo {
replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node, ctx),
ipc_renderer: data.ipc_renderer
.map(|renderer| Arc::new(Mutex::new(renderer))),
dom_width: Au::from_px(data.width as i32),
dom_height: Au::from_px(data.height as i32),
}
}
/// Returns the original inline-size of the canvas.
pub fn canvas_inline_size(&self) -> Au {
if self.replaced_image_fragment_info.writing_mode_is_vertical {
self.dom_height
} else {
self.dom_width
}
}
/// Returns the original block-size of the canvas.
pub fn canvas_block_size(&self) -> Au {
if self.replaced_image_fragment_info.writing_mode_is_vertical {
self.dom_width
} else {
self.dom_height
}
}
}
/// 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: Option<Arc<Image>>,
pub metadata: Option<ImageMetadata>,
}
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<N: ThreadSafeLayoutNode>(node: &N, url: Option<Url>,
layout_context: &LayoutContext) -> ImageFragmentInfo {
let image_or_metadata = url.and_then(|url| {
layout_context.get_or_request_image_or_meta(url, UsePlaceholder::Yes)
});
let (image, metadata) = match image_or_metadata {
Some(ImageOrMetadataAvailable::ImageAvailable(i)) => {
(Some(i.clone()), Some(ImageMetadata { height: i.height, width: i.width } ))
}
Some(ImageOrMetadataAvailable::MetadataAvailable(m)) => {
(None, Some(m))
}
None => {
(None, None)
}
};
ImageFragmentInfo {
replaced_image_fragment_info: ReplacedImageFragmentInfo::new(node, layout_context),
image: image,
metadata: metadata,
}
}
/// Returns the original inline-size of the image.
pub fn image_inline_size(&mut self) -> Au {
match self.metadata {
Some(ref metadata) => {
Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical {
metadata.height
} else {
metadata.width
} as i32)
}
None => Au(0)
}
}
/// Returns the original block-size of the image.
pub fn image_block_size(&mut self) -> Au {
match self.metadata {
Some(ref metadata) => {
Au::from_px(if self.replaced_image_fragment_info.writing_mode_is_vertical {
metadata.width
} else {
metadata.height
} as i32)
}
None => Au(0)
}
}
/// Tile an image
pub fn tile_image(position: &mut Au, size: &mut Au, virtual_position: Au, image_size: u32) {
// Avoid division by zero below!
let image_size = image_size as i32;
if image_size == 0 {
return
}
let delta_pixels = (virtual_position - *position).to_px();
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 computed_inline_size: Option<Au>,
pub computed_block_size: Option<Au>,
pub writing_mode_is_vertical: bool,
}
impl ReplacedImageFragmentInfo {
pub fn new<N>(node: &N, ctx: &LayoutContext) -> ReplacedImageFragmentInfo
where N: ThreadSafeLayoutNode {
let is_vertical = node.style(ctx.style_context()).writing_mode.is_vertical();
ReplacedImageFragmentInfo {
computed_inline_size: None,
computed_block_size: None,
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,
container_size: Option<Au>) -> MaybeAuto {
match (style_length, container_size) {
(LengthOrPercentageOrAuto::Length(length), _) => MaybeAuto::Specified(length),
(LengthOrPercentageOrAuto::Percentage(pc), Some(container_size)) => {
MaybeAuto::Specified(container_size.scale_by(pc))
}
(LengthOrPercentageOrAuto::Percentage(_), None) => MaybeAuto::Auto,
(LengthOrPercentageOrAuto::Calc(calc), Some(container_size)) => {
MaybeAuto::Specified(calc.length() + container_size.scale_by(calc.percentage()))
}
(LengthOrPercentageOrAuto::Calc(_), None) => MaybeAuto::Auto,
(LengthOrPercentageOrAuto::Auto, _) => MaybeAuto::Auto,
}
}
pub fn calculate_replaced_inline_size(&mut self,
style: &ServoComputedValues,
noncontent_inline_size: Au,
container_inline_size: Au,
container_block_size: Option<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,
Some(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_px() /
intrinsic_height.to_f32_px();
let specified_height = ReplacedImageFragmentInfo::style_length(
style_block_size,
container_block_size);
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::from_f32_px(specified_height.to_f32_px() * ratio)
}
},
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: &ServoComputedValues,
noncontent_block_size: Au,
containing_block_block_size: Option<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,
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_px() / inline_size.to_f32_px();
Au::from_f32_px(intrinsic_height.to_f32_px() / scale)
},
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 thread.
#[derive(Clone)]
pub struct IframeFragmentInfo {
/// The pipeline ID of this iframe.
pub pipeline_id: PipelineId,
}
impl IframeFragmentInfo {
/// Creates the information specific to an iframe fragment.
pub fn new<N: ThreadSafeLayoutNode>(node: &N) -> IframeFragmentInfo {
let pipeline_id = node.iframe_pipeline_id();
IframeFragmentInfo {
pipeline_id: pipeline_id,
}
}
#[inline]
pub fn calculate_replaced_inline_size(&self, style: &ServoComputedValues, 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(),
Some(containing_size),
Au::from_px(300))
}
#[inline]
pub fn calculate_replaced_block_size(&self, style: &ServoComputedValues, containing_size: Option<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: Option<Au>,
default_size: Au) -> Au {
let computed_size = match (content_size, containing_size) {
(LengthOrPercentageOrAuto::Length(length), _) => length,
(LengthOrPercentageOrAuto::Percentage(pc), Some(container_size)) => container_size.scale_by(pc),
(LengthOrPercentageOrAuto::Calc(calc), Some(container_size)) => {
container_size.scale_by(calc.percentage()) + calc.length()
},
(LengthOrPercentageOrAuto::Calc(calc), None) => calc.length(),
(LengthOrPercentageOrAuto::Percentage(_), None) => default_size,
(LengthOrPercentageOrAuto::Auto, _) => default_size,
};
let containing_size = containing_size.unwrap_or(Au(0));
clamp_size(computed_size,
style_min_size,
style_max_size,
containing_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<TextRun>,
/// The intrinsic size of the text fragment.
pub content_size: LogicalSize<Au>,
/// The byte offset of the insertion point, if any.
pub insertion_point: Option<ByteIndex>,
/// The range within the above text run that this represents.
pub range: Range<ByteIndex>,
/// The endpoint of the above range, including whitespace that was stripped out. This exists
/// so that we can restore the range to its original value (before line breaking occurred) when
/// performing incremental reflow.
pub range_end_including_stripped_whitespace: ByteIndex,
pub flags: ScannedTextFlags,
}
bitflags! {
pub flags ScannedTextFlags: u8 {
/// Whether a line break is required after this fragment if wrapping on newlines (e.g. if
/// `white-space: pre` is in effect).
const REQUIRES_LINE_BREAK_AFTERWARD_IF_WRAPPING_ON_NEWLINES = 0x01,
/// Is this fragment selected?
const SELECTED = 0x02,
}
}
impl ScannedTextFragmentInfo {
/// Creates the information specific to a scanned text fragment from a range and a text run.
pub fn new(run: Arc<TextRun>,
range: Range<ByteIndex>,
content_size: LogicalSize<Au>,
insertion_point: Option<ByteIndex>,
flags: ScannedTextFlags)
-> ScannedTextFragmentInfo {
ScannedTextFragmentInfo {
run: run,
range: range,
insertion_point: insertion_point,
content_size: content_size,
range_end_including_stripped_whitespace: range.end(),
flags: flags,
}
}
pub fn text(&self) -> &str {
&self.run.text[self.range.begin().to_usize() .. self.range.end().to_usize()]
}
pub fn requires_line_break_afterward_if_wrapping_on_newlines(&self) -> bool {
self.flags.contains(REQUIRES_LINE_BREAK_AFTERWARD_IF_WRAPPING_ON_NEWLINES)
}
pub fn selected(&self) -> bool {
self.flags.contains(SELECTED)
}
}
/// 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<ByteIndex>,
pub inline_size: Au,
}
impl SplitInfo {
fn new(range: Range<ByteIndex>, 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<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<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.
pub text: Box<str>,
/// The selected text range. An empty range represents the insertion point.
pub selection: Option<Range<ByteIndex>>,
}
impl UnscannedTextFragmentInfo {
/// Creates a new instance of `UnscannedTextFragmentInfo` from the given text.
#[inline]
pub fn new(text: String, selection: Option<Range<ByteIndex>>) -> UnscannedTextFragmentInfo {
UnscannedTextFragmentInfo {
text: text.into_boxed_str(),
selection: selection,
}
}
}
/// A fragment that represents a table column.
#[derive(Copy, Clone)]
pub struct TableColumnFragmentInfo {
/// the number of columns a <col> element should span
pub span: u32,
}
impl TableColumnFragmentInfo {
/// Create the information specific to an table column fragment.
pub fn new<N: ThreadSafeLayoutNode>(node: &N) -> TableColumnFragmentInfo {
let element = node.as_element();
let span = element.get_attr(&ns!(), &atom!("span"))
.and_then(|string| string.parse().ok())
.unwrap_or(0);
TableColumnFragmentInfo {
span: span,
}
}
}
impl Fragment {
/// Constructs a new `Fragment` instance.
pub fn new<N: ThreadSafeLayoutNode>(node: &N, specific: SpecificFragmentInfo, ctx: &LayoutContext) -> Fragment {
let style_context = ctx.style_context();
let style = node.style(style_context).clone();
let writing_mode = style.writing_mode;
let mut restyle_damage = node.restyle_damage();
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: node.opaque(),
style: style,
selected_style: node.selected_style(style_context).clone(),
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,
pseudo: node.get_pseudo_element_type().strip(),
flags: FragmentFlags::empty(),
debug_id: DebugId::new(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Constructs a new `Fragment` instance from an opaque node.
pub fn from_opaque_node_and_style(node: OpaqueNode,
pseudo: PseudoElementType<()>,
style: Arc<ServoComputedValues>,
selected_style: Arc<ServoComputedValues>,
mut restyle_damage: RestyleDamage,
specific: SpecificFragmentInfo)
-> Fragment {
let writing_mode = style.writing_mode;
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: node,
style: style,
selected_style: selected_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,
pseudo: pseudo,
flags: FragmentFlags::empty(),
debug_id: DebugId::new(),
stacking_context_id: StackingContextId::new(0),
}
}
/// 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);
let mut restyle_damage = RestyleDamage::rebuild_and_reflow();
restyle_damage.remove(RECONSTRUCT_FLOW);
Fragment {
node: self.node,
style: self.style.clone(),
selected_style: self.selected_style.clone(),
restyle_damage: restyle_damage,
border_box: new_border_box,
border_padding: self.border_padding,
margin: self.margin,
specific: info,
inline_context: self.inline_context.clone(),
pseudo: self.pseudo.clone(),
flags: FragmentFlags::empty(),
debug_id: self.debug_id.clone(),
stacking_context_id: StackingContextId::new(0),
}
}
/// Transforms this fragment using the given `SplitInfo`, preserving all the other data.
pub fn transform_with_split_info(&self, split: &SplitInfo, text_run: Arc<TextRun>)
-> Fragment {
let size = LogicalSize::new(self.style.writing_mode,
split.inline_size,
self.border_box.size.block);
// Preserve the insertion point if it is in this fragment's range or it is at line end.
let (flags, insertion_point) = match self.specific {
SpecificFragmentInfo::ScannedText(ref info) => {
match info.insertion_point {
Some(index) if split.range.contains(index) => (info.flags, info.insertion_point),
Some(index) if index == ByteIndex(text_run.text.chars().count() as isize - 1) &&
index == split.range.end() => (info.flags, info.insertion_point),
_ => (info.flags, None)
}
},
_ => (ScannedTextFlags::empty(), None)
};
let info = box ScannedTextFragmentInfo::new(
text_run,
split.range,
size,
insertion_point,
flags);
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 = LinkedList::new();
unscanned_ellipsis_fragments.push_back(self.transform(
self.border_box.size,
SpecificFragmentInfo::UnscannedText(
box UnscannedTextFragmentInfo::new("…".to_owned(), None))));
let ellipsis_fragments = TextRunScanner::new().scan_for_runs(&mut 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()
}
pub fn contains_node(&self, node_address: OpaqueNode) -> bool {
node_address == self.node ||
self.inline_context.as_ref().map_or(false, |ctx| {
ctx.contains_node(node_address)
})
}
/// 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, node_info: InlineFragmentNodeInfo) {
if self.inline_context.is_none() {
self.inline_context = Some(InlineFragmentContext::new());
}
self.inline_context.as_mut().unwrap().nodes.push(node_info);
}
/// 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::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::Multicol => {
QuantitiesIncludedInIntrinsicInlineSizes::all()
}
SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::TableWrapper => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS |
INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::TableRow => {
let base_quantities = INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
if self.style.get_inheritedtable().border_collapse ==
border_collapse::T::separate {
base_quantities | INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
} else {
base_quantities
}
}
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::UnscannedText(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::MulticolColumn => {
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 mut specified = Au(0);
if flags.contains(INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED) {
specified = MaybeAuto::from_style(style.content_inline_size(),
Au(0)).specified_or_zero();
specified = max(model::specified(style.min_inline_size(), Au(0)), specified);
if let Some(max) = model::specified_or_none(style.max_inline_size(), Au(0)) {
specified = min(specified, max)
}
}
// 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,
}
}
/// Returns a guess as to the distances from the margin edge of this fragment to its content
/// in the inline direction. This will generally be correct unless percentages are involved.
///
/// This is used for the float placement speculation logic.
pub fn guess_inline_content_edge_offsets(&self) -> SpeculatedInlineContentEdgeOffsets {
let logical_margin = self.style.logical_margin();
let logical_padding = self.style.logical_padding();
let border_width = self.border_width();
SpeculatedInlineContentEdgeOffsets {
start: MaybeAuto::from_style(logical_margin.inline_start, Au(0)).specified_or_zero() +
model::specified(logical_padding.inline_start, Au(0)) +
border_width.inline_start,
end: MaybeAuto::from_style(logical_margin.inline_end, Au(0)).specified_or_zero() +
model::specified(logical_padding.inline_end, Au(0)) +
border_width.inline_end,
}
}
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(&mut 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(_) |
SpecificFragmentInfo::InlineBlock(_) => 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.nodes.iter().fold(style_border_width, |accumulator, node| {
let mut this_border_width = node.style.logical_border_width();
if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
this_border_width.inline_start = Au(0)
}
if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
this_border_width.inline_end = Au(0)
}
accumulator + this_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);
return
}
SpecificFragmentInfo::InlineBlock(_) => {
// Inline-blocks do not take self margins into account but do account for margins
// from outer inline contexts.
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();
}
}
if let Some(ref inline_context) = self.inline_context {
for node in &inline_context.nodes {
let margin = node.style.logical_margin();
let this_inline_start_margin = if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
Au(0)
} else {
MaybeAuto::from_style(margin.inline_start,
containing_block_inline_size).specified_or_zero()
};
let this_inline_end_margin = if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
Au(0)
} else {
MaybeAuto::from_style(margin.inline_end,
containing_block_inline_size).specified_or_zero()
};
self.margin.inline_start = self.margin.inline_start + this_inline_start_margin;
self.margin.inline_end = self.margin.inline_end + this_inline_end_margin;
}
}
}
/// 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.
///
/// TODO(pcwalton): Remove `border_collapse`; we can figure it out from our style and specific
/// fragment info.
pub fn compute_border_and_padding(&mut self,
containing_block_inline_size: Au,
border_collapse: border_collapse::T) {
// Compute border.
let border = match border_collapse {
border_collapse::T::separate => self.border_width(),
border_collapse::T::collapse => LogicalMargin::zero(self.style.writing_mode),
};
// Compute padding from the fragment's style.
//
// This is zero in the case of `inline-block` because that padding is applied to the
// wrapped block, not the fragment.
let padding_from_style = match self.specific {
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::InlineBlock(_) => LogicalMargin::zero(self.style.writing_mode),
_ => model::padding_from_style(self.style(), containing_block_inline_size),
};
// Compute padding from the inline fragment context.
let padding_from_inline_fragment_context = match (&self.specific, &self.inline_context) {
(_, &None) |
(&SpecificFragmentInfo::TableColumn(_), _) |
(&SpecificFragmentInfo::TableRow, _) |
(&SpecificFragmentInfo::TableWrapper, _) => {
LogicalMargin::zero(self.style.writing_mode)
}
(_, &Some(ref inline_fragment_context)) => {
let zero_padding = LogicalMargin::zero(self.style.writing_mode);
inline_fragment_context.nodes.iter().fold(zero_padding, |accumulator, node| {
let mut padding = model::padding_from_style(&*node.style, Au(0));
if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
padding.inline_start = Au(0)
}
if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
padding.inline_end = Au(0)
}
accumulator + padding
})
}
};
self.border_padding = border + padding_from_style + padding_from_inline_fragment_context
}
// 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: &ServoComputedValues, 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)
};
if let Some(ref inline_fragment_context) = self.inline_context {
for node in &inline_fragment_context.nodes {
if node.style.get_box().position == position::T::relative {
rel_pos = rel_pos + from_style(&*node.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(&self) -> &ServoComputedValues {
&*self.style
}
#[inline(always)]
pub fn selected_style(&self) -> &ServoComputedValues {
&*self.selected_style
}
pub fn white_space(&self) -> white_space::T {
self.style().get_inheritedtext().white_space
}
pub fn color(&self) -> color::T {
self.style().get_color().color
}
/// 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, unless
/// `white-space: pre` or `white-space: nowrap` is set.
pub fn can_split(&self) -> bool {
self.is_scanned_text_fragment() && self.white_space().allow_wrap()
}
/// Returns true if and only if this fragment is a generated content fragment.
pub fn is_unscanned_generated_content(&self) -> bool {
match self.specific {
SpecificFragmentInfo::GeneratedContent(box GeneratedContentInfo::Empty) => false,
SpecificFragmentInfo::GeneratedContent(..) => true,
_ => false,
}
}
/// 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::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {}
SpecificFragmentInfo::InlineBlock(ref info) => {
let block_flow = info.flow_ref.as_block();
result.union_block(&block_flow.base.intrinsic_inline_sizes)
}
SpecificFragmentInfo::InlineAbsolute(ref 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 mut image_inline_size = match self.style.content_inline_size() {
LengthOrPercentageOrAuto::Auto |
LengthOrPercentageOrAuto::Percentage(_) => {
image_fragment_info.image_inline_size()
}
LengthOrPercentageOrAuto::Length(length) => length,
LengthOrPercentageOrAuto::Calc(calc) => calc.length(),
};
image_inline_size = max(model::specified(self.style.min_inline_size(), Au(0)), image_inline_size);
if let Some(max) = model::specified_or_none(self.style.max_inline_size(), Au(0)) {
image_inline_size = min(image_inline_size, max)
}
result.union_block(&IntrinsicISizes {
minimum_inline_size: image_inline_size,
preferred_inline_size: image_inline_size,
});
}
SpecificFragmentInfo::Canvas(ref mut canvas_fragment_info) => {
let mut canvas_inline_size = match self.style.content_inline_size() {
LengthOrPercentageOrAuto::Auto |
LengthOrPercentageOrAuto::Percentage(_) => {
canvas_fragment_info.canvas_inline_size()
}
LengthOrPercentageOrAuto::Length(length) => length,
LengthOrPercentageOrAuto::Calc(calc) => calc.length(),
};
canvas_inline_size = max(model::specified(self.style.min_inline_size(), Au(0)), canvas_inline_size);
if let Some(max) = model::specified_or_none(self.style.max_inline_size(), Au(0)) {
canvas_inline_size = min(canvas_inline_size, max)
}
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;
// 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;
let min_line_inline_size = if self.white_space().allow_wrap() {
text_fragment_info.run.min_width_for_range(range)
} else {
max_line_inline_size
};
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() {
if let Some(ref context) = self.inline_context {
for node in &context.nodes {
let mut border_width = node.style.logical_border_width();
let mut padding = model::padding_from_style(&*node.style, Au(0));
let mut margin = model::specified_margin_from_style(&*node.style);
if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
border_width.inline_start = Au(0);
padding.inline_start = Au(0);
margin.inline_start = Au(0);
}
if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
border_width.inline_end = Au(0);
padding.inline_end = Au(0);
margin.inline_end = Au(0);
}
result.surrounding_size =
result.surrounding_size +
border_width.inline_start_end() +
padding.inline_start_end() +
margin.inline_start_end();
}
}
}
result
}
/// Returns the narrowest inline-size that the first splittable part of this fragment could
/// possibly be split to. (In most cases, this returns the inline-size of the first word in
/// this fragment.)
pub fn minimum_splittable_inline_size(&self) -> Au {
match self.specific {
SpecificFragmentInfo::ScannedText(ref text) => {
text.run.minimum_splittable_inline_size(&text.range)
}
_ => Au(0),
}
}
/// 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::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineAbsolute(_) => 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 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
}
/// 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 = match self.specific {
SpecificFragmentInfo::ScannedText(ref text_fragment_info)
=> text_fragment_info,
_ => 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);
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,
slice_iterator: I,
max_inline_size: Au,
flags: SplitOptions)
-> Option<SplitResult>
where I: Iterator<Item=TextRunSlice<'a>> {
let text_fragment_info = match self.specific {
SpecificFragmentInfo::ScannedText(ref text_fragment_info)
=> text_fragment_info,
_ => return None,
};
let mut remaining_inline_size = max_inline_size;
let mut inline_start_range = Range::new(text_fragment_info.range.begin(), ByteIndex(0));
let mut inline_end_range = None;
let mut overflowing = false;
debug!("calculate_split_position_using_breaking_strategy: 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_using_breaking_strategy: considering slice \
(offset={:?}, slice range={:?}, remaining_inline_size={:?})",
slice.offset,
slice.range,
remaining_inline_size);
// Use the `remaining_inline_size` to find a split point if possible. If not, go around
// the loop again with the next slice.
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.
debug!("calculate_split_position_using_breaking_strategy: enlarging span");
remaining_inline_size = remaining_inline_size - advance;
inline_start_range.extend_by(slice.range.length());
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();
let split_is_empty = inline_start_range.is_empty() &&
!(self.requires_line_break_afterward_if_wrapping_on_newlines() &&
!self.white_space().allow_wrap());
if split_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(), ByteIndex(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);
}
// If we failed to find a suitable split point, we're on the verge of overflowing the
// line.
if split_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
}
}
break
}
let split_is_empty = inline_start_range.is_empty() &&
!self.requires_line_break_afterward_if_wrapping_on_newlines();
let inline_start = if !split_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(),
})
}
/// The opposite of `calculate_split_position_using_breaking_strategy`: merges this fragment
/// with the next one.
pub fn merge_with(&mut self, next_fragment: Fragment) {
match (&mut self.specific, &next_fragment.specific) {
(&mut SpecificFragmentInfo::ScannedText(ref mut this_info),
&SpecificFragmentInfo::ScannedText(ref other_info)) => {
debug_assert!(util::arc_ptr_eq(&this_info.run, &other_info.run));
this_info.range_end_including_stripped_whitespace =
other_info.range_end_including_stripped_whitespace;
if other_info.requires_line_break_afterward_if_wrapping_on_newlines() {
this_info.flags.insert(REQUIRES_LINE_BREAK_AFTERWARD_IF_WRAPPING_ON_NEWLINES);
}
if other_info.insertion_point.is_some() {
this_info.insertion_point = other_info.insertion_point;
}
self.border_padding.inline_end = next_fragment.border_padding.inline_end;
self.margin.inline_end = next_fragment.margin.inline_end;
}
_ => panic!("Can only merge two scanned-text fragments!"),
}
self.reset_text_range_and_inline_size();
self.meld_with_next_inline_fragment(&next_fragment);
}
/// Restore any whitespace that was stripped from a text fragment, and recompute inline metrics
/// if necessary.
pub fn reset_text_range_and_inline_size(&mut self) {
if let SpecificFragmentInfo::ScannedText(ref mut info) = self.specific {
if info.run.extra_word_spacing != Au(0) {
Arc::make_mut(&mut info.run).extra_word_spacing = Au(0);
}
// FIXME (mbrubeck): Do we need to restore leading too?
let range_end = info.range_end_including_stripped_whitespace;
if info.range.end() == range_end {
return
}
info.range.extend_to(range_end);
info.content_size.inline = info.run.metrics_for_range(&info.range).advance_width;
self.border_box.size.inline = info.content_size.inline +
self.border_padding.inline_start_end();
}
}
/// 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(&mut self,
container_inline_size: Au,
container_block_size: Option<Au>) {
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn => 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::Iframe(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::ScannedText(_) => {}
};
let style = &*self.style;
let noncontent_inline_size = self.border_padding.inline_start_end();
match self.specific {
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
let block_flow = flow_ref::deref_mut(&mut info.flow_ref).as_mut_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 = flow_ref::deref_mut(&mut info.flow_ref).as_mut_block();
self.border_box.size.inline =
max(block_flow.base.intrinsic_inline_sizes.minimum_inline_size,
block_flow.base.intrinsic_inline_sizes.preferred_inline_size);
block_flow.base.block_container_inline_size = self.border_box.size.inline;
block_flow.base.block_container_writing_mode = self.style.writing_mode;
}
SpecificFragmentInfo::InlineAbsolute(ref mut info) => {
let block_flow = flow_ref::deref_mut(&mut info.flow_ref).as_mut_block();
self.border_box.size.inline =
max(block_flow.base.intrinsic_inline_sizes.minimum_inline_size,
block_flow.base.intrinsic_inline_sizes.preferred_inline_size);
block_flow.base.block_container_inline_size = self.border_box.size.inline;
block_flow.base.block_container_writing_mode = self.style.writing_mode;
}
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,
container_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.inline =
canvas_fragment_info.replaced_image_fragment_info
.calculate_replaced_inline_size(style,
noncontent_inline_size,
container_inline_size,
container_block_size,
fragment_inline_size,
fragment_block_size);
}
SpecificFragmentInfo::Iframe(ref iframe_fragment_info) => {
self.border_box.size.inline =
iframe_fragment_info.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: Option<Au>) {
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn => 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::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::ScannedText(_) => {}
}
let style = &*self.style;
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 = flow_ref::deref_mut(&mut 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 = flow_ref::deref_mut(&mut info.flow_ref).as_block();
self.border_box.size.block = block_flow.base.position.size.block;
}
SpecificFragmentInfo::InlineAbsolute(ref mut info) => {
// Not the primary fragment, so we do not take the noncontent size into account.
let block_flow = flow_ref::deref_mut(&mut info.flow_ref).as_block();
self.border_box.size.block = block_flow.base.position.size.block +
block_flow.fragment.margin.block_start_end()
}
SpecificFragmentInfo::Iframe(ref info) => {
self.border_box.size.block =
info.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,
depth_below_baseline: self.border_padding.block_end,
ascent: computed_block_size + self.border_padding.block_start,
}
}
SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
let computed_block_size = canvas_fragment_info.replaced_image_fragment_info
.computed_block_size();
InlineMetrics {
block_size_above_baseline: computed_block_size +
self.border_padding.block_start,
depth_below_baseline: self.border_padding.block_end,
ascent: computed_block_size + self.border_padding.block_start,
}
}
SpecificFragmentInfo::ScannedText(ref info) => {
// Fragments with no glyphs don't contribute any inline metrics.
// TODO: Filter out these fragments during flow construction?
if info.insertion_point.is_none() && info.content_size.inline == Au(0) {
return InlineMetrics::new(Au(0), Au(0), Au(0));
}
// See CSS 2.1 § 10.8.1.
let line_height = self.calculate_line_height(layout_context);
let font_derived_metrics =
InlineMetrics::from_font_metrics(&info.run.font_metrics, line_height);
InlineMetrics {
block_size_above_baseline: font_derived_metrics.block_size_above_baseline +
self.border_padding.block_start,
depth_below_baseline: font_derived_metrics.depth_below_baseline +
self.border_padding.block_end,
ascent: font_derived_metrics.ascent + self.border_padding.block_start,
}
}
SpecificFragmentInfo::InlineBlock(ref info) => {
// See CSS 2.1 § 10.8.1.
let flow = &info.flow_ref;
let block_flow = flow.as_block();
let baseline_offset = match flow.baseline_offset_of_last_line_box_in_flow() {
Some(baseline_offset) => baseline_offset,
None => block_flow.fragment.border_box.size.block,
};
let start_margin = block_flow.fragment.margin.block_start;
let end_margin = block_flow.fragment.margin.block_end;
let depth_below_baseline = flow::base(&**flow).position.size.block -
baseline_offset + end_margin;
InlineMetrics::new(baseline_offset + start_margin,
depth_below_baseline,
baseline_offset)
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineAbsolute(_) => {
// 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 immediately-following fragment or
/// false otherwise.
pub fn can_merge_with_fragment(&self, other: &Fragment) -> bool {
match (&self.specific, &other.specific) {
(&SpecificFragmentInfo::UnscannedText(ref first_unscanned_text),
&SpecificFragmentInfo::UnscannedText(_)) => {
// FIXME: Should probably use a whitelist of styles that can safely differ (#3165)
if self.style().get_font() != other.style().get_font() ||
self.text_decoration() != other.text_decoration() ||
self.white_space() != other.white_space() ||
self.color() != other.color() {
return false
}
if first_unscanned_text.text.ends_with('\n') {
return false
}
// If this node has any styles that have border/padding/margins on the following
// side, then we can't merge with the next fragment.
if let Some(ref inline_context) = self.inline_context {
for inline_context_node in inline_context.nodes.iter() {
if !inline_context_node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
continue
}
if inline_context_node.style.logical_margin().inline_end !=
LengthOrPercentageOrAuto::Length(Au(0)) {
return false
}
if inline_context_node.style.logical_padding().inline_end !=
LengthOrPercentage::Length(Au(0)) {
return false
}
if inline_context_node.style.logical_border_width().inline_end != Au(0) {
return false
}
}
}
// If the next fragment has any styles that have border/padding/margins on the
// preceding side, then it can't merge with us.
if let Some(ref inline_context) = other.inline_context {
for inline_context_node in inline_context.nodes.iter() {
if !inline_context_node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
continue
}
if inline_context_node.style.logical_margin().inline_start !=
LengthOrPercentageOrAuto::Length(Au(0)) {
return false
}
if inline_context_node.style.logical_padding().inline_start !=
LengthOrPercentage::Length(Au(0)) {
return false
}
if inline_context_node.style.logical_border_width().inline_start != Au(0) {
return false
}
}
}
true
}
_ => 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::InlineAbsolute(_) |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::TableWrapper => false,
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::UnscannedText(_) => true,
}
}
/// Determines the inline sizes of inline-block fragments. These cannot be fully computed until
/// inline size assignment has run for the child flow: thus it is computed "late", during
/// block size assignment.
pub fn update_late_computed_replaced_inline_size_if_necessary(&mut self) {
if let SpecificFragmentInfo::InlineBlock(ref mut inline_block_info) = self.specific {
let block_flow = flow_ref::deref_mut(&mut inline_block_info.flow_ref).as_block();
let margin = block_flow.fragment.style.logical_margin();
self.border_box.size.inline = block_flow.fragment.border_box.size.inline +
MaybeAuto::from_style(margin.inline_start, Au(0)).specified_or_zero() +
MaybeAuto::from_style(margin.inline_end, Au(0)).specified_or_zero()
}
}
pub fn update_late_computed_inline_position_if_necessary(&mut self) {
if let SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) = self.specific {
let position = self.border_box.start.i;
flow_ref::deref_mut(&mut info.flow_ref)
.update_late_computed_inline_position_if_necessary(position)
}
}
pub fn update_late_computed_block_position_if_necessary(&mut self) {
if let SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) = self.specific {
let position = self.border_box.start.b;
flow_ref::deref_mut(&mut info.flow_ref)
.update_late_computed_block_position_if_necessary(position)
}
}
pub fn repair_style(&mut self, new_style: &Arc<ServoComputedValues>) {
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 `Own` 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>,
relative_containing_block_mode: WritingMode,
coordinate_system: CoordinateSystem)
-> Rect<Au> {
let container_size =
relative_containing_block_size.to_physical(relative_containing_block_mode);
let border_box = self.border_box.to_physical(self.style.writing_mode, container_size);
if coordinate_system == CoordinateSystem::Own && self.establishes_stacking_context() {
return Rect::new(Point2D::zero(), 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::new(Point2D::new(stacking_relative_border_box.origin.x + border_padding.left,
stacking_relative_border_box.origin.y + border_padding.top),
Size2D::new(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 {
// Text fragments shouldn't create stacking contexts.
match self.specific {
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::UnscannedText(_) => return false,
_ => {}
}
if self.flags.contains(HAS_LAYER) {
return true
}
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
}
if self.style().get_effects().transform.0.is_some() {
return true
}
match self.style().get_used_transform_style() {
transform_style::T::flat | transform_style::T::preserve_3d => {
return true
}
transform_style::T::auto => {}
}
// FIXME(pcwalton): Don't unconditionally form stacking contexts for `overflow_x: scroll`
// and `overflow_y: scroll`. This needs multiple layers per stacking context.
match (self.style().get_box().position,
self.style().get_position().z_index,
self.style().get_box().overflow_x,
self.style().get_box().overflow_y.0) {
(position::T::absolute,
z_index::T::Auto,
overflow_x::T::visible,
overflow_x::T::visible) |
(position::T::fixed,
z_index::T::Auto,
overflow_x::T::visible,
overflow_x::T::visible) |
(position::T::relative,
z_index::T::Auto,
overflow_x::T::visible,
overflow_x::T::visible) => false,
(position::T::absolute, _, _, _) |
(position::T::fixed, _, _, _) |
(position::T::relative, _, _, _) |
(_, _, overflow_x::T::auto, _) |
(_, _, overflow_x::T::scroll, _) |
(_, _, _, overflow_x::T::auto) |
(_, _, _, overflow_x::T::scroll) => true,
(position::T::static_, _, _, _) => false
}
}
// Get the effective z-index of this fragment. Z-indices only apply to positioned element
// per CSS 2 9.9.1 (http://www.w3.org/TR/CSS2/visuren.html#z-index), so this value may differ
// from the value specified in the style.
pub fn effective_z_index(&self) -> i32 {
match self.style().get_box().position {
position::T::static_ => {},
_ => return self.style().get_position().z_index.number_or_zero(),
}
if self.style().get_effects().transform.0.is_some() {
return self.style().get_position().z_index.number_or_zero();
}
match self.style().get_box().display {
display::T::flex => self.style().get_position().z_index.number_or_zero(),
_ => 0,
}
}
/// Computes the overflow rect of this fragment relative to the start of the flow.
pub fn compute_overflow(&self,
flow_size: &Size2D<Au>,
relative_containing_block_size: &LogicalSize<Au>)
-> Overflow {
let mut border_box = self.border_box.to_physical(self.style.writing_mode, *flow_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(relative_containing_block_size);
border_box =
border_box.translate_by_size(&relative_position.to_physical(self.style.writing_mode));
let mut overflow = Overflow::from_rect(&border_box);
// Box shadows cause us to draw outside our border box.
for box_shadow in &self.style().get_effects().box_shadow.0 {
let offset = Point2D::new(box_shadow.offset_x, box_shadow.offset_y);
let inflation = box_shadow.spread_radius + box_shadow.blur_radius *
BLUR_INFLATION_FACTOR;
overflow.paint = overflow.paint.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.paint = overflow.paint.union(&border_box.inflate(outline_width,
outline_width))
}
// Include the overflow of the block flow, if any.
match self.specific {
SpecificFragmentInfo::InlineBlock(ref info) => {
let block_flow = info.flow_ref.as_block();
overflow.union(&flow::base(block_flow).overflow);
}
SpecificFragmentInfo::InlineAbsolute(ref info) => {
let block_flow = info.flow_ref.as_block();
overflow.union(&flow::base(block_flow).overflow);
}
_ => (),
}
// FIXME(pcwalton): Sometimes excessively fancy glyphs can make us draw outside our border
// box too.
overflow
}
pub fn requires_line_break_afterward_if_wrapping_on_newlines(&self) -> bool {
match self.specific {
SpecificFragmentInfo::ScannedText(ref scanned_text) => {
scanned_text.requires_line_break_afterward_if_wrapping_on_newlines()
}
_ => false,
}
}
pub fn strip_leading_whitespace_if_necessary(&mut self) -> WhitespaceStrippingResult {
if self.white_space().preserve_spaces() {
return WhitespaceStrippingResult::RetainFragment
}
match self.specific {
SpecificFragmentInfo::ScannedText(ref mut scanned_text_fragment_info) => {
let leading_whitespace_byte_count = scanned_text_fragment_info.text()
.find(|c| !char_is_whitespace(c))
.unwrap_or(scanned_text_fragment_info.text().len());
let whitespace_len = ByteIndex(leading_whitespace_byte_count as isize);
let whitespace_range = Range::new(scanned_text_fragment_info.range.begin(),
whitespace_len);
let text_bounds =
scanned_text_fragment_info.run.metrics_for_range(&whitespace_range).bounding_box;
self.border_box.size.inline = self.border_box.size.inline - text_bounds.size.width;
scanned_text_fragment_info.content_size.inline =
scanned_text_fragment_info.content_size.inline - text_bounds.size.width;
scanned_text_fragment_info.range.adjust_by(whitespace_len, -whitespace_len);
WhitespaceStrippingResult::RetainFragment
}
SpecificFragmentInfo::UnscannedText(ref mut unscanned_text_fragment_info) => {
let mut new_text_string = String::new();
let mut modified = false;
for (i, character) in unscanned_text_fragment_info.text.char_indices() {
if gfx::text::util::is_bidi_control(character) {
new_text_string.push(character);
continue
}
if char_is_whitespace(character) {
modified = true;
continue
}
// Finished processing leading control chars and whitespace.
if modified {
new_text_string.push_str(&unscanned_text_fragment_info.text[i..]);
}
break
}
if modified {
unscanned_text_fragment_info.text = new_text_string.into_boxed_str();
}
WhitespaceStrippingResult::from_unscanned_text_fragment_info(
&unscanned_text_fragment_info)
}
_ => WhitespaceStrippingResult::RetainFragment,
}
}
/// Returns true if the entire fragment was stripped.
pub fn strip_trailing_whitespace_if_necessary(&mut self) -> WhitespaceStrippingResult {
if self.white_space().preserve_spaces() {
return WhitespaceStrippingResult::RetainFragment
}
match self.specific {
SpecificFragmentInfo::ScannedText(ref mut scanned_text_fragment_info) => {
let mut trailing_whitespace_start_byte = 0;
for (i, c) in scanned_text_fragment_info.text().char_indices().rev() {
if !char_is_whitespace(c) {
trailing_whitespace_start_byte = i + c.len_utf8();
break;
}
}
let whitespace_start = ByteIndex(trailing_whitespace_start_byte as isize);
let whitespace_len = scanned_text_fragment_info.range.length() - whitespace_start;
let mut whitespace_range = Range::new(whitespace_start, whitespace_len);
whitespace_range.shift_by(scanned_text_fragment_info.range.begin());
let text_bounds = scanned_text_fragment_info.run
.metrics_for_range(&whitespace_range)
.bounding_box;
self.border_box.size.inline -= text_bounds.size.width;
scanned_text_fragment_info.content_size.inline -= text_bounds.size.width;
scanned_text_fragment_info.range.extend_by(-whitespace_len);
WhitespaceStrippingResult::RetainFragment
}
SpecificFragmentInfo::UnscannedText(ref mut unscanned_text_fragment_info) => {
let mut trailing_bidi_control_characters_to_retain = Vec::new();
let (mut modified, mut last_character_index) = (true, 0);
for (i, character) in unscanned_text_fragment_info.text.char_indices().rev() {
if gfx::text::util::is_bidi_control(character) {
trailing_bidi_control_characters_to_retain.push(character);
continue
}
if char_is_whitespace(character) {
modified = true;
continue
}
last_character_index = i + character.len_utf8();
break
}
if modified {
let mut text = unscanned_text_fragment_info.text.to_string();
text.truncate(last_character_index);
for character in trailing_bidi_control_characters_to_retain.iter().rev() {
text.push(*character);
}
unscanned_text_fragment_info.text = text.into_boxed_str();
}
WhitespaceStrippingResult::from_unscanned_text_fragment_info(
&unscanned_text_fragment_info)
}
_ => WhitespaceStrippingResult::RetainFragment,
}
}
pub fn inline_styles(&self) -> InlineStyleIterator {
InlineStyleIterator::new(self)
}
/// Returns the inline-size of this fragment's margin box.
pub fn margin_box_inline_size(&self) -> Au {
self.border_box.size.inline + self.margin.inline_start_end()
}
/// Returns true if this node *or any of the nodes within its inline fragment context* have
/// non-`static` `position`.
pub fn is_positioned(&self) -> bool {
if self.style.get_box().position != position::T::static_ {
return true
}
if let Some(ref inline_context) = self.inline_context {
for node in inline_context.nodes.iter() {
if node.style.get_box().position != position::T::static_ {
return true
}
}
}
false
}
/// Returns true if this node is absolutely positioned.
pub fn is_absolutely_positioned(&self) -> bool {
self.style.get_box().position == position::T::absolute
}
pub fn is_inline_absolute(&self) -> bool {
match self.specific {
SpecificFragmentInfo::InlineAbsolute(..) => true,
_ => false,
}
}
pub fn meld_with_next_inline_fragment(&mut self, next_fragment: &Fragment) {
if let Some(ref mut inline_context_of_this_fragment) = self.inline_context {
if let Some(ref inline_context_of_next_fragment) = next_fragment.inline_context {
for (inline_context_node_from_this_fragment,
inline_context_node_from_next_fragment)
in inline_context_of_this_fragment.nodes.iter_mut().rev()
.zip(inline_context_of_next_fragment.nodes.iter().rev())
{
if !inline_context_node_from_next_fragment.flags.contains(
LAST_FRAGMENT_OF_ELEMENT) {
continue
}
if inline_context_node_from_next_fragment.address !=
inline_context_node_from_this_fragment.address {
continue
}
inline_context_node_from_this_fragment.flags.insert(LAST_FRAGMENT_OF_ELEMENT);
}
}
}
}
pub fn meld_with_prev_inline_fragment(&mut self, prev_fragment: &Fragment) {
if let Some(ref mut inline_context_of_this_fragment) = self.inline_context {
if let Some(ref inline_context_of_prev_fragment) = prev_fragment.inline_context {
for (inline_context_node_from_prev_fragment,
inline_context_node_from_this_fragment)
in inline_context_of_prev_fragment.nodes.iter().rev().zip(
inline_context_of_this_fragment.nodes.iter_mut().rev())
{
if !inline_context_node_from_prev_fragment.flags.contains(
FIRST_FRAGMENT_OF_ELEMENT) {
continue
}
if inline_context_node_from_prev_fragment.address !=
inline_context_node_from_this_fragment.address {
continue
}
inline_context_node_from_this_fragment.flags.insert(
FIRST_FRAGMENT_OF_ELEMENT);
}
}
}
}
pub fn fragment_id(&self) -> usize {
return self as *const Fragment as usize;
}
pub fn fragment_type(&self) -> FragmentType {
match self.pseudo {
PseudoElementType::Normal => FragmentType::FragmentBody,
PseudoElementType::Before(_) => FragmentType::BeforePseudoContent,
PseudoElementType::After(_) => FragmentType::AfterPseudoContent,
PseudoElementType::DetailsSummary(_) => FragmentType::FragmentBody,
PseudoElementType::DetailsContent(_) => FragmentType::FragmentBody,
}
}
pub fn layer_id(&self) -> LayerId {
let layer_type = match self.pseudo {
PseudoElementType::Normal => LayerType::FragmentBody,
PseudoElementType::Before(_) => LayerType::BeforePseudoContent,
PseudoElementType::After(_) => LayerType::AfterPseudoContent,
PseudoElementType::DetailsSummary(_) => LayerType::FragmentBody,
PseudoElementType::DetailsContent(_) => LayerType::FragmentBody,
};
LayerId::new_of_type(layer_type, self.node.id() as usize)
}
pub fn layer_id_for_overflow_scroll(&self) -> LayerId {
LayerId::new_of_type(LayerType::OverflowScroll, self.node.id() as usize)
}
/// Returns true if any of the inline styles associated with this fragment have
/// `vertical-align` set to `top` or `bottom`.
pub fn is_vertically_aligned_to_top_or_bottom(&self) -> bool {
match self.style.get_box().vertical_align {
vertical_align::T::top | vertical_align::T::bottom => return true,
_ => {}
}
if let Some(ref inline_context) = self.inline_context {
for node in &inline_context.nodes {
match node.style.get_box().vertical_align {
vertical_align::T::top | vertical_align::T::bottom => return true,
_ => {}
}
}
}
false
}
pub fn is_text_or_replaced(&self) -> bool {
match self.specific {
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper => false,
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::UnscannedText(_) => true
}
}
}
impl fmt::Debug for Fragment {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let border_padding_string = if !self.border_padding.is_zero() {
format!(" border_padding={:?}", self.border_padding)
} else {
"".to_owned()
};
let margin_string = if !self.margin.is_zero() {
format!(" margin={:?}", self.margin)
} else {
"".to_owned()
};
let damage_string = if self.restyle_damage != RestyleDamage::empty() {
format!(" damage={:?}", self.restyle_damage)
} else {
"".to_owned()
};
write!(f, "{}({}) [{:?}] border_box={:?}{}{}{}",
self.specific.get_type(),
self.debug_id,
self.specific,
self.border_box,
border_padding_string,
margin_string,
damage_string)
}
}
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, level: i32, 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.
Own,
}
pub struct InlineStyleIterator<'a> {
fragment: &'a Fragment,
inline_style_index: usize,
primary_style_yielded: bool,
}
impl<'a> Iterator for InlineStyleIterator<'a> {
type Item = &'a ServoComputedValues;
fn next(&mut self) -> Option<&'a ServoComputedValues> {
if !self.primary_style_yielded {
self.primary_style_yielded = true;
return Some(&*self.fragment.style)
}
let inline_context = match self.fragment.inline_context {
None => return None,
Some(ref inline_context) => inline_context,
};
let inline_style_index = self.inline_style_index;
if inline_style_index == inline_context.nodes.len() {
return None
}
self.inline_style_index += 1;
Some(&*inline_context.nodes[inline_style_index].style)
}
}
impl<'a> InlineStyleIterator<'a> {
fn new(fragment: &Fragment) -> InlineStyleIterator {
InlineStyleIterator {
fragment: fragment,
inline_style_index: 0,
primary_style_yielded: false,
}
}
}
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum WhitespaceStrippingResult {
RetainFragment,
FragmentContainedOnlyBidiControlCharacters,
FragmentContainedOnlyWhitespace,
}
impl WhitespaceStrippingResult {
fn from_unscanned_text_fragment_info(info: &UnscannedTextFragmentInfo)
-> WhitespaceStrippingResult {
if info.text.is_empty() {
WhitespaceStrippingResult::FragmentContainedOnlyWhitespace
} else if info.text.chars().all(gfx::text::util::is_bidi_control) {
WhitespaceStrippingResult::FragmentContainedOnlyBidiControlCharacters
} else {
WhitespaceStrippingResult::RetainFragment
}
}
}
/// The overflow area. We need two different notions of overflow: paint overflow and scrollable
/// overflow.
#[derive(Copy, Clone, Debug)]
pub struct Overflow {
pub scroll: Rect<Au>,
pub paint: Rect<Au>,
}
impl Overflow {
pub fn new() -> Overflow {
Overflow {
scroll: Rect::zero(),
paint: Rect::zero(),
}
}
pub fn from_rect(border_box: &Rect<Au>) -> Overflow {
Overflow {
scroll: *border_box,
paint: *border_box,
}
}
pub fn union(&mut self, other: &Overflow) {
self.scroll = self.scroll.union(&other.scroll);
self.paint = self.paint.union(&other.paint);
}
pub fn translate(&mut self, point: &Point2D<Au>) {
self.scroll = self.scroll.translate(point);
self.paint = self.paint.translate(point);
}
}
bitflags! {
pub flags FragmentFlags: u8 {
/// Whether this fragment has a layer.
const HAS_LAYER = 0x01,
}
}
/// Specified distances from the margin edge of a block to its content in the inline direction.
/// These are returned by `guess_inline_content_edge_offsets()` and are used in the float placement
/// speculation logic.
#[derive(Copy, Clone, Debug)]
pub struct SpeculatedInlineContentEdgeOffsets {
pub start: Au,
pub end: Au,
}
#[cfg(not(debug_assertions))]
#[derive(Clone)]
struct DebugId;
#[cfg(debug_assertions)]
#[derive(Clone)]
struct DebugId(u16);
#[cfg(not(debug_assertions))]
impl DebugId {
pub fn new() -> DebugId {
DebugId
}
}
#[cfg(debug_assertions)]
impl DebugId {
pub fn new() -> DebugId {
DebugId(layout_debug::generate_unique_debug_id())
}
}
#[cfg(not(debug_assertions))]
impl fmt::Display for DebugId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:p}", &self)
}
}
#[cfg(debug_assertions)]
impl fmt::Display for DebugId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.0)
}
}
#[cfg(not(debug_assertions))]
impl Encodable for DebugId {
fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
e.emit_str(&format!("{:p}", &self))
}
}
#[cfg(debug_assertions)]
impl Encodable for DebugId {
fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
e.emit_u16(self.0)
}
}
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