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servo: Merge #13602 - layout: Rewrite Servo's `vertical-align` support to match CSS 2.1 § 10.8, and implement `vertical-align: middle` per CSS 2.1 § 10.8.1 (from pcwalton:vertical-align-middle); r=mbrubeck 

`InlineMetrics` has been split into `InlineMetrics` for fragments and
`LineMetrics` for lines. Both structures' fields have been renamed in
order to more clearly delineate the difference between *space* and
*content*. Vertical positioning of fragments has been reworked to take
margins and borders into account only for replaced content.

This patch fixes the `vertical_align_super_a.html` reftest. Servo now
matches the rendering that Gecko and WebKit produce.

Additionally, this includes a test for the popular inline-block
centering technique described here:
https://s.codepen.io/shshaw/fullpage/gEiDt?#Inline-Block

r? @mbrubeck

Source-Repo: https://github.com/servo/servo
Source-Revision: 768a699fa5d822173b2247d6348413d09951a8bb
This commit is contained in:
Patrick Walton 2016-10-11 15:33:47 -05:00
Родитель 73f07d709c
Коммит e87bbe3700
7 изменённых файлов: 376 добавлений и 320 удалений
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4
servo/components/gfx/platform/macos/font.rs
Просмотреть файл

@ -306,7 +306,7 @@ impl FontHandleMethods for FontHandle {
.map(Au::from_f64_px)
.unwrap_or(max_advance_width);
let metrics = FontMetrics {
let metrics = FontMetrics {
underline_size: au_from_pt(self.ctfont.underline_thickness() as f64),
// TODO(Issue #201): underline metrics are not reliable. Have to pull out of font table
// directly.
@ -317,7 +317,7 @@ impl FontHandleMethods for FontHandle {
strikeout_size: Au(0), // FIXME(Issue #942)
strikeout_offset: Au(0), // FIXME(Issue #942)
leading: au_from_pt(leading),
x_height: au_from_pt(self.ctfont.x_height() as f64),
x_height: au_from_pt((self.ctfont.x_height() as f64) * scale),
em_size: em_size,
ascent: au_from_pt(ascent * scale),
descent: au_from_pt(descent * scale),

11
servo/components/layout/construct.rs
Просмотреть файл

@ -476,14 +476,9 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
{
// FIXME(#6503): Use Arc::get_mut().unwrap() here.
let inline_flow = flow_ref::deref_mut(&mut inline_flow_ref).as_mut_inline();
let (ascent, descent) =
inline_flow.compute_minimum_ascent_and_descent(&mut self.layout_context
.font_context(),
&node.style(self.style_context()));
inline_flow.minimum_block_size_above_baseline = ascent;
inline_flow.minimum_depth_below_baseline = descent;
inline_flow.minimum_line_metrics =
inline_flow.minimum_line_metrics(&mut self.layout_context.font_context(),
&node.style(self.style_context()))
}
inline_flow_ref.finish();

4
servo/components/layout/flow.rs
Просмотреть файл

@ -1401,7 +1401,7 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
for kid in base(self).children.iter().rev() {
if kid.is_inline_flow() {
if let Some(baseline_offset) = kid.as_inline().baseline_offset_of_last_line() {
return Some(baseline_offset)
return Some(base(kid).position.start.b + baseline_offset)
}
}
if kid.is_block_like() &&
@ -1576,7 +1576,7 @@ impl ContainingBlockLink {
if flow.is_block_like() {
flow.as_block().explicit_block_containing_size(shared_context)
} else if flow.is_inline_flow() {
Some(flow.as_inline().minimum_block_size_above_baseline)
Some(flow.as_inline().minimum_line_metrics.space_above_baseline)
} else {
None
}

223
servo/components/layout/fragment.rs
Просмотреть файл

@ -19,7 +19,7 @@ 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 inline::{InlineMetrics, LAST_FRAGMENT_OF_ELEMENT, LineMetrics};
use ipc_channel::ipc::IpcSender;
#[cfg(debug_assertions)]
use layout_debug;
@ -54,6 +54,10 @@ use text;
use text::TextRunScanner;
use url::Url;
// From gfxFontConstants.h in Firefox.
static FONT_SUBSCRIPT_OFFSET_RATIO: f32 = 0.20;
static FONT_SUPERSCRIPT_OFFSET_RATIO: f32 = 0.34;
/// 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:
@ -643,6 +647,7 @@ impl ReplacedImageFragmentInfo {
inline_size + noncontent_inline_size
}
/// Here, `noncontent_block_size` represents the sum of border and padding, but not margin.
pub fn calculate_replaced_block_size(&mut self,
style: &ServoComputedValues,
noncontent_block_size: Au,
@ -650,7 +655,6 @@ impl ReplacedImageFragmentInfo {
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();
@ -1178,13 +1182,6 @@ impl Fragment {
}
}
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]
@ -2132,38 +2129,52 @@ impl Fragment {
}
}
/// Returns true if this fragment is replaced content or an inline-block or false otherwise.
pub fn is_replaced_or_inline_block(&self) -> bool {
match self.specific {
SpecificFragmentInfo::Canvas(_) |
SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::Svg(_) => true,
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::InlineAbsolute(_) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::ScannedText(_) |
SpecificFragmentInfo::UnscannedText(_) => false,
}
}
/// 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 {
return match self.specific {
SpecificFragmentInfo::Image(ref image_fragment_info) => {
let computed_block_size = image_fragment_info.replaced_image_fragment_info
.computed_block_size();
///
/// This does not take `vertical-align` into account. For that, use `aligned_inline_metrics()`.
fn content_inline_metrics(&self, layout_context: &LayoutContext) -> InlineMetrics {
// CSS 2.1 § 10.8: "The height of each inline-level box in the line box is
// calculated. For replaced elements, inline-block elements, and inline-table
// elements, this is the height of their margin box."
//
// FIXME(pcwalton): We have to handle `Generic` and `GeneratedContent` here to avoid
// crashing in a couple of `css21_dev/html4/content-` WPTs, but I don't see how those two
// fragment types should end up inside inlines. (In the case of `GeneratedContent`, those
// fragment types should have been resolved by now…)
let inline_metrics = match self.specific {
SpecificFragmentInfo::Canvas(_) | SpecificFragmentInfo::Iframe(_) |
SpecificFragmentInfo::Image(_) | SpecificFragmentInfo::Svg(_) |
SpecificFragmentInfo::Generic | SpecificFragmentInfo::GeneratedContent(_) => {
let ascent = self.border_box.size.block + self.margin.block_start;
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::Svg(ref svg_fragment_info) => {
let computed_block_size = svg_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,
space_above_baseline: ascent,
space_below_baseline: self.margin.block_end,
ascent: ascent,
}
}
SpecificFragmentInfo::ScannedText(ref info) => {
@ -2173,14 +2184,10 @@ impl Fragment {
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,
depth_below_baseline: font_derived_metrics.depth_below_baseline,
ascent: font_derived_metrics.ascent + self.border_padding.block_start,
}
let font_metrics = text::font_metrics_for_style(&mut layout_context.font_context(),
self.style.get_font_arc());
let line_height = text::line_height_from_style(&*self.style, &font_metrics);
InlineMetrics::from_font_metrics(&info.run.font_metrics, line_height)
}
SpecificFragmentInfo::InlineBlock(ref info) => {
inline_metrics_of_block(&info.flow_ref, &*self.style)
@ -2191,21 +2198,26 @@ impl Fragment {
SpecificFragmentInfo::InlineAbsolute(_) => {
InlineMetrics::new(Au(0), Au(0), Au(0))
}
_ => {
InlineMetrics {
block_size_above_baseline: self.border_box.size.block,
depth_below_baseline: Au(0),
ascent: self.border_box.size.block,
}
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableColumn(_) |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::Multicol |
SpecificFragmentInfo::MulticolColumn |
SpecificFragmentInfo::UnscannedText(_) => {
unreachable!("Shouldn't see fragments of this type here!")
}
};
return inline_metrics;
fn inline_metrics_of_block(flow: &FlowRef, style: &ServoComputedValues) -> InlineMetrics {
// See CSS 2.1 § 10.8.1.
// CSS 2.1 § 10.8: "The height of each inline-level box in the line box is calculated.
// For replaced elements, inline-block elements, and inline-table elements, this is the
// height of their margin box."
let block_flow = flow.as_block();
let is_auto = style.get_position().height == LengthOrPercentageOrAuto::Auto;
let baseline_offset = flow.baseline_offset_of_last_line_box_in_flow();
let baseline_offset = match baseline_offset {
let baseline_offset = match flow.baseline_offset_of_last_line_box_in_flow() {
Some(baseline_offset) if is_auto => baseline_offset,
_ => block_flow.fragment.border_box.size.block,
};
@ -2218,6 +2230,107 @@ impl Fragment {
}
}
/// Calculates the offset from the baseline that applies to this fragment due to
/// `vertical-align`. Positive values represent downward displacement.
///
/// If `actual_line_metrics` is supplied, then these metrics are used to determine the
/// displacement of the fragment when `top` or `bottom` `vertical-align` values are
/// encountered. If this is not supplied, then `top` and `bottom` values are ignored.
fn vertical_alignment_offset(&self,
layout_context: &LayoutContext,
content_inline_metrics: &InlineMetrics,
minimum_line_metrics: &LineMetrics,
actual_line_metrics: Option<&LineMetrics>)
-> Au {
let mut offset = Au(0);
for style in self.inline_styles() {
// If any of the inline styles say `top` or `bottom`, adjust the vertical align
// appropriately.
//
// FIXME(#5624, pcwalton): This passes our current reftests but isn't the right thing
// to do.
match style.get_box().vertical_align {
vertical_align::T::baseline => {}
vertical_align::T::middle => {
let font_metrics =
text::font_metrics_for_style(&mut layout_context.font_context(),
style.get_font_arc());
offset += (content_inline_metrics.ascent -
content_inline_metrics.space_below_baseline -
font_metrics.x_height).scale_by(0.5)
}
vertical_align::T::sub => {
offset += minimum_line_metrics.space_needed()
.scale_by(FONT_SUBSCRIPT_OFFSET_RATIO)
}
vertical_align::T::super_ => {
offset -= minimum_line_metrics.space_needed()
.scale_by(FONT_SUPERSCRIPT_OFFSET_RATIO)
}
vertical_align::T::text_top => {
offset = self.content_inline_metrics(layout_context).ascent -
minimum_line_metrics.space_above_baseline
}
vertical_align::T::text_bottom => {
offset = minimum_line_metrics.space_below_baseline -
self.content_inline_metrics(layout_context).space_below_baseline
}
vertical_align::T::top => {
if let Some(actual_line_metrics) = actual_line_metrics {
offset = content_inline_metrics.ascent -
actual_line_metrics.space_above_baseline
}
}
vertical_align::T::bottom => {
if let Some(actual_line_metrics) = actual_line_metrics {
offset = actual_line_metrics.space_below_baseline -
content_inline_metrics.space_below_baseline
}
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Length(length)) => {
offset -= length
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Percentage(
percentage)) => {
offset -= minimum_line_metrics.space_needed().scale_by(percentage)
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Calc(formula)) => {
offset -= minimum_line_metrics.space_needed().scale_by(formula.percentage()) +
formula.length()
}
}
}
offset
}
/// Calculates block-size above baseline, depth below baseline, and ascent for this fragment
/// when used in an inline formatting context, taking `vertical-align` (other than `top` or
/// `bottom`) into account. See CSS 2.1 § 10.8.1.
///
/// If `actual_line_metrics` is supplied, then these metrics are used to determine the
/// displacement of the fragment when `top` or `bottom` `vertical-align` values are
/// encountered. If this is not supplied, then `top` and `bottom` values are ignored.
pub fn aligned_inline_metrics(&self,
layout_context: &LayoutContext,
minimum_line_metrics: &LineMetrics,
actual_line_metrics: Option<&LineMetrics>)
-> InlineMetrics {
let content_inline_metrics = self.content_inline_metrics(layout_context);
let vertical_alignment_offset = self.vertical_alignment_offset(layout_context,
&content_inline_metrics,
minimum_line_metrics,
actual_line_metrics);
let mut space_above_baseline = match actual_line_metrics {
None => content_inline_metrics.space_above_baseline,
Some(actual_line_metrics) => actual_line_metrics.space_above_baseline,
};
space_above_baseline = space_above_baseline - vertical_alignment_offset;
let space_below_baseline = content_inline_metrics.space_below_baseline +
vertical_alignment_offset;
let ascent = content_inline_metrics.ascent - vertical_alignment_offset;
InlineMetrics::new(space_above_baseline, space_below_baseline, ascent)
}
/// 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 {

431
servo/components/layout/inline.rs
Просмотреть файл

@ -37,14 +37,9 @@ use style::computed_values::{text_overflow, vertical_align, white_space};
use style::context::{SharedStyleContext, StyleContext};
use style::logical_geometry::{LogicalRect, LogicalSize, WritingMode};
use style::properties::ServoComputedValues;
use style::values::computed::LengthOrPercentage;
use text;
use unicode_bidi;
// From gfxFontConstants.h in Firefox
static FONT_SUBSCRIPT_OFFSET_RATIO: f32 = 0.20;
static FONT_SUPERSCRIPT_OFFSET_RATIO: f32 = 0.34;
/// `Line`s are represented as offsets into the child list, rather than
/// as an object that "owns" fragments. Choosing a different set of line
/// breaks requires a new list of offsets, and possibly some splitting and
@ -158,31 +153,22 @@ pub struct Line {
/// ~~~
pub green_zone: LogicalSize<Au>,
/// The minimum block size above the baseline for this line, as specified by the style.
pub minimum_block_size_above_baseline: Au,
/// The minimum metrics for this line, as specified by the style.
pub minimum_metrics: LineMetrics,
/// The minimum depth below the baseline for this line, as specified by the style.
pub minimum_depth_below_baseline: Au,
/// The inline metrics for this line.
pub inline_metrics: InlineMetrics,
/// The actual metrics for this line.
pub metrics: LineMetrics,
}
impl Line {
fn new(writing_mode: WritingMode,
minimum_block_size_above_baseline: Au,
minimum_depth_below_baseline: Au)
-> Line {
fn new(writing_mode: WritingMode, minimum_metrics: &LineMetrics) -> Line {
Line {
range: Range::empty(),
visual_runs: None,
bounds: LogicalRect::zero(writing_mode),
green_zone: LogicalSize::zero(writing_mode),
minimum_block_size_above_baseline: minimum_block_size_above_baseline,
minimum_depth_below_baseline: minimum_depth_below_baseline,
inline_metrics: InlineMetrics::new(minimum_block_size_above_baseline,
minimum_depth_below_baseline,
minimum_block_size_above_baseline),
minimum_metrics: *minimum_metrics,
metrics: *minimum_metrics,
}
}
@ -190,29 +176,31 @@ impl Line {
///
/// FIXME(pcwalton): this assumes that the tallest fragment in the line determines the line
/// block-size. This might not be the case with some weird text fonts.
fn new_inline_metrics(&self, new_fragment: &Fragment, layout_context: &LayoutContext)
-> InlineMetrics {
fn new_metrics_for_fragment(&self, new_fragment: &Fragment, layout_context: &LayoutContext)
-> LineMetrics {
if !new_fragment.is_vertically_aligned_to_top_or_bottom() {
let fragment_inline_metrics = new_fragment.inline_metrics(layout_context);
self.inline_metrics.max(&fragment_inline_metrics)
let fragment_inline_metrics =
new_fragment.aligned_inline_metrics(layout_context, &self.minimum_metrics, None);
self.metrics.new_metrics_for_fragment(&fragment_inline_metrics)
} else {
self.inline_metrics
self.metrics
}
}
/// Returns the new block size that this line would have if `new_fragment` were added to it.
/// `new_inline_metrics` represents the new inline metrics that this line would have; it can
/// be computed with `new_inline_metrics()`.
fn new_block_size(&self,
new_fragment: &Fragment,
new_inline_metrics: &InlineMetrics,
layout_context: &LayoutContext)
-> Au {
fn new_block_size_for_fragment(&self,
new_fragment: &Fragment,
new_line_metrics: &LineMetrics,
layout_context: &LayoutContext)
-> Au {
let new_block_size = if new_fragment.is_vertically_aligned_to_top_or_bottom() {
max(new_fragment.inline_metrics(layout_context).block_size(),
self.minimum_block_size_above_baseline + self.minimum_depth_below_baseline)
max(new_fragment.aligned_inline_metrics(layout_context, &self.minimum_metrics, None)
.space_needed(),
self.minimum_metrics.space_needed())
} else {
new_inline_metrics.block_size()
new_line_metrics.space_needed()
};
max(self.bounds.size.block, new_block_size)
}
@ -243,34 +231,24 @@ struct LineBreaker {
cur_b: Au,
/// The computed value of the indentation for the first line (`text-indent`, CSS 2.1 § 16.1).
first_line_indentation: Au,
/// The minimum block-size above the baseline for each line, as specified by the line height
/// and font style.
minimum_block_size_above_baseline: Au,
/// The minimum depth below the baseline for each line, as specified by the line height and
/// font style.
minimum_depth_below_baseline: Au,
/// The minimum metrics for each line, as specified by the line height and font style.
minimum_metrics: LineMetrics,
}
impl LineBreaker {
/// Creates a new `LineBreaker` with a set of floats and the indentation of the first line.
fn new(float_context: Floats,
first_line_indentation: Au,
minimum_block_size_above_baseline: Au,
minimum_depth_below_baseline: Au)
fn new(float_context: Floats, first_line_indentation: Au, minimum_line_metrics: &LineMetrics)
-> LineBreaker {
LineBreaker {
new_fragments: Vec::new(),
work_list: VecDeque::new(),
pending_line: Line::new(float_context.writing_mode,
minimum_block_size_above_baseline,
minimum_depth_below_baseline),
pending_line: Line::new(float_context.writing_mode, minimum_line_metrics),
floats: float_context,
lines: Vec::new(),
cur_b: Au(0),
last_known_line_breaking_opportunity: None,
first_line_indentation: first_line_indentation,
minimum_block_size_above_baseline: minimum_block_size_above_baseline,
minimum_depth_below_baseline: minimum_depth_below_baseline,
minimum_metrics: *minimum_line_metrics,
}
}
@ -285,9 +263,8 @@ impl LineBreaker {
/// Reinitializes the pending line to blank data.
fn reset_line(&mut self) -> Line {
self.last_known_line_breaking_opportunity = None;
mem::replace(&mut self.pending_line, Line::new(self.floats.writing_mode,
self.minimum_block_size_above_baseline,
self.minimum_depth_below_baseline))
mem::replace(&mut self.pending_line,
Line::new(self.floats.writing_mode, &self.minimum_metrics))
}
/// Reflows fragments for the given inline flow.
@ -574,10 +551,11 @@ impl LineBreaker {
// `green_zone.block < self.pending_line.bounds.size.block`, then we committed a line that
// overlaps with floats.
let green_zone = self.pending_line.green_zone;
let new_inline_metrics = self.pending_line.new_inline_metrics(&fragment, layout_context);
let new_block_size = self.pending_line.new_block_size(&fragment,
&new_inline_metrics,
layout_context);
let new_line_metrics = self.pending_line.new_metrics_for_fragment(&fragment,
layout_context);
let new_block_size = self.pending_line.new_block_size_for_fragment(&fragment,
&new_line_metrics,
layout_context);
if new_block_size > green_zone.block {
// Uh-oh. Float collision imminent. Enter the float collision avoider!
if !self.avoid_floats(flow, fragment, new_block_size) {
@ -747,14 +725,13 @@ impl LineBreaker {
if !fragment.is_inline_absolute() && !fragment.is_hypothetical() {
self.pending_line.bounds.size.inline = self.pending_line.bounds.size.inline +
fragment.margin_box_inline_size() +
indentation;
self.pending_line.inline_metrics =
self.pending_line.new_inline_metrics(&fragment, layout_context);
fragment.margin_box_inline_size() + indentation;
self.pending_line.metrics = self.pending_line.new_metrics_for_fragment(&fragment,
layout_context);
self.pending_line.bounds.size.block =
self.pending_line.new_block_size(&fragment,
&self.pending_line.inline_metrics,
layout_context);
self.pending_line.new_block_size_for_fragment(&fragment,
&self.pending_line.metrics,
layout_context);
}
self.new_fragments.push(fragment);
@ -864,13 +841,8 @@ pub struct InlineFlow {
/// lines.
pub lines: Vec<Line>,
/// The minimum block-size above the baseline for each line, as specified by the line height
/// and font style.
pub minimum_block_size_above_baseline: Au,
/// The minimum depth below the baseline for each line, as specified by the line height and
/// font style.
pub minimum_depth_below_baseline: Au,
/// The minimum metrics for each line, as specified by the line height and font style.
pub minimum_line_metrics: LineMetrics,
/// The amount of indentation to use on the first line. This is determined by our block parent
/// (because percentages are relative to the containing block, and we aren't in a position to
@ -884,8 +856,7 @@ impl InlineFlow {
base: BaseFlow::new(None, writing_mode, ForceNonfloatedFlag::ForceNonfloated),
fragments: fragments,
lines: Vec::new(),
minimum_block_size_above_baseline: Au(0),
minimum_depth_below_baseline: Au(0),
minimum_line_metrics: LineMetrics::new(Au(0), Au(0)),
first_line_indentation: Au(0),
};
@ -1050,90 +1021,62 @@ impl InlineFlow {
/// Sets final fragment positions in the block direction for one line.
fn set_block_fragment_positions(fragments: &mut InlineFragments,
line: &Line,
minimum_block_size_above_baseline: Au,
minimum_depth_below_baseline: Au,
minimum_line_metrics: &LineMetrics,
layout_context: &LayoutContext) {
for fragment_index in line.range.each_index() {
// If any of the inline styles say `top` or `bottom`, adjust the vertical align
// appropriately.
//
// FIXME(#5624, pcwalton): This passes our current reftests but isn't the right thing
// to do.
let fragment = fragments.get_mut(fragment_index.to_usize());
let fragment_inline_metrics = fragment.inline_metrics(layout_context);
let line_block_metrics = LineBlockMetrics::new(line, fragment, layout_context);
let mut block_start = line_block_metrics.start +
line_block_metrics.size_above_baseline -
fragment_inline_metrics.ascent;
let line_metrics = LineMetrics::for_line_and_fragment(line, fragment, layout_context);
let inline_metrics = fragment.aligned_inline_metrics(layout_context,
minimum_line_metrics,
Some(&line_metrics));
for style in fragment.inline_styles() {
match style.get_box().vertical_align {
vertical_align::T::baseline => {}
vertical_align::T::middle => {}
vertical_align::T::sub => {
let sub_offset =
(minimum_block_size_above_baseline +
minimum_depth_below_baseline).scale_by(FONT_SUBSCRIPT_OFFSET_RATIO);
block_start = block_start + sub_offset
}
vertical_align::T::super_ => {
let super_offset =
(minimum_block_size_above_baseline +
minimum_depth_below_baseline).scale_by(FONT_SUPERSCRIPT_OFFSET_RATIO);
block_start = block_start - super_offset
}
vertical_align::T::text_top => {
block_start = line_block_metrics.start +
line_block_metrics.size_above_baseline -
minimum_block_size_above_baseline
}
vertical_align::T::text_bottom => {
block_start = line_block_metrics.start +
line_block_metrics.size_above_baseline +
minimum_depth_below_baseline -
fragment.border_box.size.block
}
vertical_align::T::top => {
block_start = line_block_metrics.start
}
vertical_align::T::bottom => {
block_start = line_block_metrics.start + line_block_metrics.size -
fragment.border_box.size.block
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Length(length)) => {
block_start = block_start - length
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Percentage(
percentage)) => {
let line_height = fragment.calculate_line_height(layout_context);
let length = line_height.scale_by(percentage);
block_start = block_start - length
}
vertical_align::T::LengthOrPercentage(LengthOrPercentage::Calc(calc)) => {
let line_height = fragment.calculate_line_height(layout_context);
let percentage_length = line_height.scale_by(calc.percentage());
block_start = block_start - percentage_length - calc.length()
}
}
// Align the top of the fragment's border box with its ascent above the baseline.
fragment.border_box.start.b = line.bounds.start.b + line_metrics.space_above_baseline -
inline_metrics.ascent;
// CSS 2.1 § 10.8: "The height of each inline-level box in the line box is
// calculated. For replaced elements, inline-block elements, and inline-table
// elements, this is the height of their margin box; for inline boxes, this is their
// 'line-height'."
//
// CSS 2.1 § 10.8.1: "Although margins, borders, and padding of non-replaced elements
// do not enter into the line box calculation, they are still rendered around inline
// boxes."
//
// Effectively, if the fragment is a non-replaced element (excluding inline-block), we
// need to align its ascent above the baseline with the top of the *content box*, not
// the border box. Since the code above has already aligned it to the border box, we
// simply need to adjust it in this case.
if !fragment.is_replaced_or_inline_block() {
fragment.border_box.start.b -= fragment.border_padding.block_start
}
fragment.border_box.start.b = block_start;
fragment.update_late_computed_block_position_if_necessary();
}
}
/// Computes the minimum ascent and descent for each line. This is done during flow
/// construction.
/// Computes the minimum metrics for each line. This is done during flow construction.
///
/// `style` is the style of the block.
pub fn compute_minimum_ascent_and_descent(&self,
pub fn minimum_line_metrics(&self, font_context: &mut FontContext, style: &ServoComputedValues)
-> LineMetrics {
InlineFlow::minimum_line_metrics_for_fragments(&self.fragments.fragments,
font_context,
style)
}
/// Computes the minimum line metrics for the given fragments. This is typically done during
/// flow construction.
///
/// `style` is the style of the block that these fragments belong to.
pub fn minimum_line_metrics_for_fragments(fragments: &[Fragment],
font_context: &mut FontContext,
style: &ServoComputedValues)
-> (Au, Au) {
-> LineMetrics {
// As a special case, if this flow contains only hypothetical fragments, then the entire
// flow is hypothetical and takes up no space. See CSS 2.1 § 10.3.7.
if self.fragments.fragments.iter().all(|fragment| fragment.is_hypothetical()) {
return (Au(0), Au(0))
if fragments.iter().all(Fragment::is_hypothetical) {
return LineMetrics::new(Au(0), Au(0))
}
let font_style = style.get_font_arc();
@ -1141,86 +1084,73 @@ impl InlineFlow {
let line_height = text::line_height_from_style(style, &font_metrics);
let inline_metrics = InlineMetrics::from_font_metrics(&font_metrics, line_height);
let mut block_size_above_baseline = Au(0);
let mut depth_below_baseline = Au(i32::MIN);
let mut line_metrics = LineMetrics::new(Au(0), Au(i32::MIN));
let mut largest_block_size_for_top_fragments = Au(0);
let mut largest_block_size_for_bottom_fragments = Au(0);
// We use `vertical_align::T::baseline` here because `vertical-align` must not apply to
// the inside of inline blocks.
update_inline_metrics(&inline_metrics,
style.get_box().display,
vertical_align::T::baseline,
&mut block_size_above_baseline,
&mut depth_below_baseline,
&mut largest_block_size_for_top_fragments,
&mut largest_block_size_for_bottom_fragments);
update_line_metrics_for_fragment(&mut line_metrics,
&inline_metrics,
style.get_box().display,
vertical_align::T::baseline,
&mut largest_block_size_for_top_fragments,
&mut largest_block_size_for_bottom_fragments);
// According to CSS 2.1 § 10.8, `line-height` of any inline element specifies the minimal
// height of line boxes within the element.
for frag in &self.fragments.fragments {
if let Some(ref inline_context) = frag.inline_context {
for node in &inline_context.nodes {
let font_style = node.style.get_font_arc();
let font_metrics = text::font_metrics_for_style(font_context, font_style);
let line_height = text::line_height_from_style(&*node.style, &font_metrics);
let inline_metrics = InlineMetrics::from_font_metrics(&font_metrics,
line_height);
for inline_context in fragments.iter()
.filter_map(|fragment| fragment.inline_context.as_ref()) {
for node in &inline_context.nodes {
let font_style = node.style.get_font_arc();
let font_metrics = text::font_metrics_for_style(font_context, font_style);
let line_height = text::line_height_from_style(&*node.style, &font_metrics);
let inline_metrics = InlineMetrics::from_font_metrics(&font_metrics, line_height);
update_inline_metrics(&inline_metrics,
node.style.get_box().display,
node.style.get_box().vertical_align,
&mut block_size_above_baseline,
&mut depth_below_baseline,
&mut largest_block_size_for_top_fragments,
&mut largest_block_size_for_bottom_fragments);
update_line_metrics_for_fragment(&mut line_metrics,
&inline_metrics,
node.style.get_box().display,
node.style.get_box().vertical_align,
&mut largest_block_size_for_top_fragments,
&mut largest_block_size_for_bottom_fragments);
}
}
}
block_size_above_baseline =
max(block_size_above_baseline,
largest_block_size_for_bottom_fragments - max(depth_below_baseline, Au(0)));
depth_below_baseline =
max(depth_below_baseline,
largest_block_size_for_top_fragments - block_size_above_baseline);
line_metrics.space_above_baseline =
max(line_metrics.space_above_baseline,
largest_block_size_for_bottom_fragments - max(line_metrics.space_below_baseline,
Au(0)));
line_metrics.space_below_baseline =
max(line_metrics.space_below_baseline,
largest_block_size_for_top_fragments - line_metrics.space_above_baseline);
return (block_size_above_baseline, depth_below_baseline);
return line_metrics;
fn update_inline_metrics(inline_metrics: &InlineMetrics,
display_value: display::T,
vertical_align_value: vertical_align::T,
block_size_above_baseline: &mut Au,
depth_below_baseline: &mut Au,
largest_block_size_for_top_fragments: &mut Au,
largest_block_size_for_bottom_fragments: &mut Au) {
fn update_line_metrics_for_fragment(line_metrics: &mut LineMetrics,
inline_metrics: &InlineMetrics,
display_value: display::T,
vertical_align_value: vertical_align::T,
largest_block_size_for_top_fragments: &mut Au,
largest_block_size_for_bottom_fragments: &mut Au) {
match (display_value, vertical_align_value) {
(display::T::inline, vertical_align::T::top) |
(display::T::block, vertical_align::T::top) |
(display::T::inline_block, vertical_align::T::top) if
inline_metrics.block_size_above_baseline >= Au(0) => {
*largest_block_size_for_top_fragments =
max(*largest_block_size_for_top_fragments,
inline_metrics.block_size_above_baseline +
inline_metrics.depth_below_baseline)
inline_metrics.space_above_baseline >= Au(0) => {
*largest_block_size_for_top_fragments = max(
*largest_block_size_for_top_fragments,
inline_metrics.space_above_baseline + inline_metrics.space_below_baseline)
}
(display::T::inline, vertical_align::T::bottom) |
(display::T::block, vertical_align::T::bottom) |
(display::T::inline_block, vertical_align::T::bottom) if
inline_metrics.depth_below_baseline >= Au(0) => {
*largest_block_size_for_bottom_fragments =
max(*largest_block_size_for_bottom_fragments,
inline_metrics.block_size_above_baseline +
inline_metrics.depth_below_baseline)
}
_ => {
*block_size_above_baseline =
max(*block_size_above_baseline,
inline_metrics.block_size_above_baseline);
*depth_below_baseline = max(*depth_below_baseline,
inline_metrics.depth_below_baseline);
inline_metrics.space_below_baseline >= Au(0) => {
*largest_block_size_for_bottom_fragments = max(
*largest_block_size_for_bottom_fragments,
inline_metrics.space_above_baseline + inline_metrics.space_below_baseline)
}
_ => *line_metrics = line_metrics.new_metrics_for_fragment(inline_metrics),
}
}
}
@ -1284,7 +1214,7 @@ impl InlineFlow {
pub fn baseline_offset_of_last_line(&self) -> Option<Au> {
self.last_line_containing_real_fragments().map(|line| {
line.bounds.start.b + line.bounds.size.block - line.inline_metrics.depth_below_baseline
line.bounds.start.b + line.bounds.size.block - line.metrics.space_below_baseline
})
}
@ -1476,8 +1406,7 @@ impl Flow for InlineFlow {
// Perform line breaking.
let mut scanner = LineBreaker::new(self.base.floats.clone(),
indentation,
self.minimum_block_size_above_baseline,
self.minimum_depth_below_baseline);
&self.minimum_line_metrics);
scanner.scan_for_lines(self, layout_context);
// Now, go through each line and lay out the fragments inside.
@ -1493,8 +1422,7 @@ impl Flow for InlineFlow {
// Compute the final positions in the block direction of each fragment.
InlineFlow::set_block_fragment_positions(&mut self.fragments,
line,
self.minimum_block_size_above_baseline,
self.minimum_depth_below_baseline,
&self.minimum_line_metrics,
layout_context);
// This is used to set the block-start position of the next line in the next iteration
@ -1849,22 +1777,28 @@ fn inline_contexts_are_equal(inline_context_a: &Option<InlineFragmentContext>,
}
}
/// Block-size above the baseline, depth below the baseline, and ascent for a fragment. See CSS 2.1
/// § 10.8.1.
/// Ascent and space needed above and below the baseline for a fragment. See CSS 2.1 § 10.8.1.
///
/// Descent is not included in this structure because it can be computed from the fragment's
/// border/content box and the ascent.
#[derive(Clone, Copy, Debug, RustcEncodable)]
pub struct InlineMetrics {
pub block_size_above_baseline: Au,
pub depth_below_baseline: Au,
/// The amount of space above the baseline needed for this fragment.
pub space_above_baseline: Au,
/// The amount of space below the baseline needed for this fragment.
pub space_below_baseline: Au,
/// The distance from the baseline to the top of this fragment. This can differ from
/// `block_size_above_baseline` if the fragment needs some empty space above it due to
/// line-height, etc.
pub ascent: Au,
}
impl InlineMetrics {
/// Creates a new set of inline metrics.
pub fn new(block_size_above_baseline: Au, depth_below_baseline: Au, ascent: Au)
-> InlineMetrics {
pub fn new(space_above_baseline: Au, space_below_baseline: Au, ascent: Au) -> InlineMetrics {
InlineMetrics {
block_size_above_baseline: block_size_above_baseline,
depth_below_baseline: depth_below_baseline,
space_above_baseline: space_above_baseline,
space_below_baseline: space_below_baseline,
ascent: ascent,
}
}
@ -1873,29 +1807,22 @@ impl InlineMetrics {
#[inline]
pub fn from_font_metrics(font_metrics: &FontMetrics, line_height: Au) -> InlineMetrics {
let leading = line_height - (font_metrics.ascent + font_metrics.descent);
// Calculating the half leading here and then using leading - half_leading
// below ensure that we don't introduce any rounding accuracy issues here.
// The invariant is that the resulting total line height must exactly
// equal the requested line_height.
let half_leading = leading.scale_by(0.5);
InlineMetrics {
block_size_above_baseline: font_metrics.ascent + half_leading,
depth_below_baseline: font_metrics.descent + leading - half_leading,
space_above_baseline: font_metrics.ascent + half_leading,
space_below_baseline: font_metrics.descent + leading - half_leading,
ascent: font_metrics.ascent,
}
}
pub fn block_size(&self) -> Au {
self.block_size_above_baseline + self.depth_below_baseline
}
pub fn max(&self, other: &InlineMetrics) -> InlineMetrics {
InlineMetrics {
block_size_above_baseline: max(self.block_size_above_baseline,
other.block_size_above_baseline),
depth_below_baseline: max(self.depth_below_baseline, other.depth_below_baseline),
ascent: max(self.ascent, other.ascent),
}
/// Returns the sum of the space needed above and below the baseline.
fn space_needed(&self) -> Au {
self.space_above_baseline + self.space_below_baseline
}
}
@ -1905,31 +1832,55 @@ enum LineFlushMode {
Flush,
}
struct LineBlockMetrics {
start: Au,
size: Au,
size_above_baseline: Au,
#[derive(Copy, Clone, Debug, RustcEncodable)]
pub struct LineMetrics {
pub space_above_baseline: Au,
pub space_below_baseline: Au,
}
impl LineBlockMetrics {
fn new(line: &Line, fragment: &Fragment, layout_context: &LayoutContext) -> LineBlockMetrics {
impl LineMetrics {
pub fn new(space_above_baseline: Au, space_below_baseline: Au) -> LineMetrics {
LineMetrics {
space_above_baseline: space_above_baseline,
space_below_baseline: space_below_baseline,
}
}
/// Returns the line metrics that result from combining the line that these metrics represent
/// with a fragment with the given metrics.
fn new_metrics_for_fragment(&self, fragment_inline_metrics: &InlineMetrics) -> LineMetrics {
LineMetrics {
space_above_baseline: max(self.space_above_baseline,
fragment_inline_metrics.space_above_baseline),
space_below_baseline: max(self.space_below_baseline,
fragment_inline_metrics.space_below_baseline),
}
}
fn for_line_and_fragment(line: &Line, fragment: &Fragment, layout_context: &LayoutContext)
-> LineMetrics {
if !fragment.is_hypothetical() {
return LineBlockMetrics {
start: line.bounds.start.b,
size: line.bounds.size.block,
size_above_baseline: line.inline_metrics.block_size_above_baseline,
let space_above_baseline = line.metrics.space_above_baseline;
return LineMetrics {
space_above_baseline: space_above_baseline,
space_below_baseline: line.bounds.size.block - space_above_baseline,
}
}
let hypothetical_inline_metrics = line.new_inline_metrics(fragment, layout_context);
let hypothetical_block_size = line.new_block_size(fragment,
&hypothetical_inline_metrics,
layout_context);
LineBlockMetrics {
start: line.bounds.start.b,
size: hypothetical_block_size,
size_above_baseline: hypothetical_inline_metrics.block_size_above_baseline,
let hypothetical_line_metrics = line.new_metrics_for_fragment(fragment, layout_context);
let hypothetical_block_size = line.new_block_size_for_fragment(fragment,
&hypothetical_line_metrics,
layout_context);
let hypothetical_space_above_baseline = hypothetical_line_metrics.space_above_baseline;
LineMetrics {
space_above_baseline: hypothetical_space_above_baseline,
space_below_baseline: hypothetical_block_size - hypothetical_space_above_baseline,
}
}
/// Returns the sum of the space needed above and below the baseline.
pub fn space_needed(&self) -> Au {
self.space_above_baseline + self.space_below_baseline
}
}

22
servo/components/layout/list_item.rs
Просмотреть файл

@ -18,14 +18,13 @@ use fragment::{CoordinateSystem, Fragment, FragmentBorderBoxIterator, GeneratedC
use fragment::Overflow;
use generated_content;
use gfx::display_list::StackingContext;
use inline::InlineMetrics;
use inline::InlineFlow;
use script_layout_interface::restyle_damage::RESOLVE_GENERATED_CONTENT;
use std::sync::Arc;
use style::computed_values::{list_style_type, position};
use style::context::SharedStyleContext;
use style::logical_geometry::LogicalSize;
use style::properties::ServoComputedValues;
use text;
/// A block with the CSS `display` property equal to `list-item`.
#[derive(Debug)]
@ -105,21 +104,20 @@ impl Flow for ListItemFlow {
fn assign_block_size<'a>(&mut self, layout_context: &'a LayoutContext<'a>) {
self.block_flow.assign_block_size(layout_context);
// FIXME(pcwalton): Do this during flow construction, like `InlineFlow` does?
let marker_line_metrics =
InlineFlow::minimum_line_metrics_for_fragments(&self.marker_fragments,
&mut layout_context.font_context(),
&*self.block_flow.fragment.style);
for marker in &mut self.marker_fragments {
let containing_block_block_size =
self.block_flow.base.block_container_explicit_block_size;
marker.assign_replaced_block_size_if_necessary(containing_block_block_size);
let font_metrics =
text::font_metrics_for_style(&mut layout_context.font_context(),
marker.style.get_font_arc());
let line_height = text::line_height_from_style(&*marker.style, &font_metrics);
let item_inline_metrics = InlineMetrics::from_font_metrics(&font_metrics, line_height);
let marker_inline_metrics = marker.inline_metrics(layout_context);
marker.border_box.start.b = item_inline_metrics.block_size_above_baseline -
let marker_inline_metrics = marker.aligned_inline_metrics(layout_context,
&marker_line_metrics,
Some(&marker_line_metrics));
marker.border_box.start.b = marker_line_metrics.space_above_baseline -
marker_inline_metrics.ascent;
marker.border_box.size.block = marker_inline_metrics.ascent +
marker_inline_metrics.depth_below_baseline;
}
}

1
servo/resources/servo.css
Просмотреть файл

@ -42,7 +42,6 @@ input[type="reset"] {
border-right: solid 1px #999999;
border-bottom: solid 1px #999999;
text-align: center;
vertical-align: middle;
color: black;
}