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servo/components/layout/display_list_builder.rs
Patrick Walton 14a544b64c layout: Clip the immediate fragments of block flows that establish 
stacking contexts properly.

The code that existed before correctly translated the clips of child
elements, but not those of immediate display items belonging to the flow
itself.

Makes Leaflet.js maps usable.
2015-04-15 17:19:27 -07:00

1626 lines
84 KiB
Rust
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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/. */
//! Builds display lists from flows and fragments.
//!
//! Other browser engines sometimes call this "painting", but it is more accurately called display
//! list building, as the actual painting does not happen here—only deciding *what* we're going to
//! paint.
#![deny(unsafe_code)]
use azure::azure_hl::Color;
use block::BlockFlow;
use canvas::canvas_paint_task::CanvasMsg::SendPixelContents;
use context::LayoutContext;
use flow::{self, BaseFlow, Flow, IS_ABSOLUTELY_POSITIONED, NEEDS_LAYER};
use fragment::{CoordinateSystem, Fragment, IframeFragmentInfo, ImageFragmentInfo};
use fragment::{ScannedTextFragmentInfo, SpecificFragmentInfo};
use inline::InlineFlow;
use list_item::ListItemFlow;
use model::{self, MaybeAuto, ToGfxMatrix};
use opaque_node::OpaqueNodeMethods;
use geom::{Matrix2D, Point2D, Rect, Size2D, SideOffsets2D};
use gfx::color;
use gfx::display_list::{BLUR_INFLATION_FACTOR, BaseDisplayItem, BorderDisplayItem};
use gfx::display_list::{BorderRadii, BoxShadowClipMode, BoxShadowDisplayItem, ClippingRegion};
use gfx::display_list::{DisplayItem, DisplayList, DisplayItemMetadata};
use gfx::display_list::{GradientDisplayItem};
use gfx::display_list::{GradientStop, ImageDisplayItem, LineDisplayItem};
use gfx::display_list::{OpaqueNode, SolidColorDisplayItem};
use gfx::display_list::{StackingContext, TextDisplayItem, TextOrientation};
use gfx::paint_task::{PaintLayer, THREAD_TINT_COLORS};
use png::{self, PixelsByColorType};
use msg::compositor_msg::ScrollPolicy;
use msg::constellation_msg::Msg as ConstellationMsg;
use msg::constellation_msg::ConstellationChan;
use net_traits::image::holder::ImageHolder;
use util::cursor::Cursor;
use util::geometry::{self, Au, ZERO_POINT, to_px, to_frac_px};
use util::logical_geometry::{LogicalPoint, LogicalRect, LogicalSize, WritingMode};
use util::opts;
use std::cmp;
use std::default::Default;
use std::iter::repeat;
use std::num::Float;
use style::values::specified::{AngleOrCorner, HorizontalDirection, VerticalDirection};
use style::values::computed::{Image, LinearGradient, LengthOrPercentage, LengthOrPercentageOrAuto};
use style::values::RGBA;
use style::computed_values::filter::Filter;
use style::computed_values::transform::ComputedMatrix;
use style::computed_values::{background_attachment, background_repeat, background_size};
use style::computed_values::{border_style, image_rendering, overflow_x, position, visibility};
use style::properties::style_structs::Border;
use style::properties::ComputedValues;
use std::num::ToPrimitive;
use std::sync::Arc;
use std::sync::mpsc::channel;
use url::Url;
/// The results of display list building for a single flow.
pub enum DisplayListBuildingResult {
None,
StackingContext(Arc<StackingContext>),
Normal(Box<DisplayList>),
}
impl DisplayListBuildingResult {
/// Adds the display list items contained within this display list building result to the given
/// display list, preserving stacking order. If this display list building result does not
/// consist of an entire stacking context, it will be emptied.
pub fn add_to(&mut self, display_list: &mut DisplayList) {
match *self {
DisplayListBuildingResult::None => return,
DisplayListBuildingResult::StackingContext(ref mut stacking_context) => {
display_list.children.push_back((*stacking_context).clone())
}
DisplayListBuildingResult::Normal(ref mut source_display_list) => {
display_list.append_from(&mut **source_display_list)
}
}
}
}
pub trait FragmentDisplayListBuilding {
/// Adds the display items necessary to paint the background of this fragment to the display
/// list if necessary.
fn build_display_list_for_background_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion);
/// Computes the background size for an image with the given background area according to the
/// rules in CSS-BACKGROUNDS § 3.9.
fn compute_background_image_size(&self,
style: &ComputedValues,
bounds: &Rect<Au>,
image: &png::Image)
-> Size2D<Au>;
/// Adds the display items necessary to paint the background image of this fragment to the
/// display list at the appropriate stacking level.
fn build_display_list_for_background_image(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion,
image_url: &Url);
/// Adds the display items necessary to paint the background linear gradient of this fragment
/// to the display list at the appropriate stacking level.
fn build_display_list_for_background_linear_gradient(&self,
display_list: &mut DisplayList,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion,
gradient: &LinearGradient,
style: &ComputedValues);
/// Adds the display items necessary to paint the borders of this fragment to a display list if
/// necessary.
fn build_display_list_for_borders_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
abs_bounds: &Rect<Au>,
level: StackingLevel,
clip: &ClippingRegion);
/// Adds the display items necessary to paint the outline of this fragment to the display list
/// if necessary.
fn build_display_list_for_outline_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
bounds: &Rect<Au>,
clip: &ClippingRegion);
/// Adds the display items necessary to paint the box shadow of this fragment to the display
/// list if necessary.
fn build_display_list_for_box_shadow_if_applicable(&self,
style: &ComputedValues,
list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion);
/// Adds display items necessary to draw debug boxes around a scanned text fragment.
fn build_debug_borders_around_text_fragments(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
stacking_relative_content_box: &Rect<Au>,
text_fragment: &ScannedTextFragmentInfo,
clip: &ClippingRegion);
/// Adds display items necessary to draw debug boxes around this fragment.
fn build_debug_borders_around_fragment(&self,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
clip: &ClippingRegion);
/// Adds the display items for this fragment to the given display list.
///
/// Arguments:
///
/// * `display_list`: The display list to add display items to.
/// * `layout_context`: The layout context.
/// * `dirty`: The dirty rectangle in the coordinate system of the owning flow.
/// * `stacking_relative_flow_origin`: Position of the origin of the owning flow with respect
/// to its nearest ancestor stacking context.
/// * `relative_containing_block_size`: The size of the containing block that
/// `position: relative` makes use of.
/// * `clip`: The region to clip the display items to.
fn build_display_list(&mut self,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
stacking_relative_flow_origin: &Point2D<Au>,
relative_containing_block_size: &LogicalSize<Au>,
relative_containing_block_mode: WritingMode,
background_and_border_level: BackgroundAndBorderLevel,
clip: &ClippingRegion);
/// Sends the size and position of this iframe fragment to the constellation. This is out of
/// line to guide inlining.
fn finalize_position_and_size_of_iframe(&self,
iframe_fragment: &IframeFragmentInfo,
offset: Point2D<Au>,
layout_context: &LayoutContext);
/// Returns the appropriate clipping region for descendants of this flow.
fn clipping_region_for_children(&self,
current_clip: &ClippingRegion,
stacking_relative_border_box: &Rect<Au>)
-> ClippingRegion;
/// Calculates the clipping rectangle for a fragment, taking the `clip` property into account
/// per CSS 2.1 § 11.1.2.
fn calculate_style_specified_clip(&self,
parent_clip: &ClippingRegion,
stacking_relative_border_box: &Rect<Au>)
-> ClippingRegion;
/// Creates the text display item for one text fragment. This can be called multiple times for
/// one fragment if there are text shadows.
///
/// `shadow_blur_radius` will be `Some` if this is a shadow, even if the blur radius is zero.
fn build_display_list_for_text_fragment(&self,
display_list: &mut DisplayList,
text_fragment: &ScannedTextFragmentInfo,
text_color: RGBA,
stacking_relative_content_box: &Rect<Au>,
shadow_blur_radius: Option<Au>,
offset: &Point2D<Au>,
clip: &ClippingRegion);
/// Creates the display item for a text decoration: underline, overline, or line-through.
fn build_display_list_for_text_decoration(&self,
display_list: &mut DisplayList,
color: &RGBA,
stacking_relative_box: &LogicalRect<Au>,
clip: &ClippingRegion,
blur_radius: Au);
/// A helper method that `build_display_list` calls to create per-fragment-type display items.
fn build_fragment_type_specific_display_items(&mut self,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
clip: &ClippingRegion);
}
fn handle_overlapping_radii(size: &Size2D<Au>, radii: &BorderRadii<Au>) -> BorderRadii<Au> {
// No two corners' border radii may add up to more than the length of the edge
// between them. To prevent that, all radii are scaled down uniformly.
fn scale_factor(radius_a: Au, radius_b: Au, edge_length: Au) -> f64 {
let required = radius_a + radius_b;
if required <= edge_length {
1.0
} else {
to_frac_px(edge_length) / to_frac_px(required)
}
}
let top_factor = scale_factor(radii.top_left, radii.top_right, size.width);
let bottom_factor = scale_factor(radii.bottom_left, radii.bottom_right, size.width);
let left_factor = scale_factor(radii.top_left, radii.bottom_left, size.height);
let right_factor = scale_factor(radii.top_right, radii.bottom_right, size.height);
let min_factor = top_factor.min(bottom_factor).min(left_factor).min(right_factor);
if min_factor < 1.0 {
BorderRadii {
top_left: radii.top_left .scale_by(min_factor),
top_right: radii.top_right .scale_by(min_factor),
bottom_left: radii.bottom_left .scale_by(min_factor),
bottom_right: radii.bottom_right.scale_by(min_factor),
}
} else {
*radii
}
}
fn build_border_radius(abs_bounds: &Rect<Au>, border_style: &Border) -> BorderRadii<Au> {
// TODO(cgaebel): Support border radii even in the case of multiple border widths.
// This is an extension of supporting elliptical radii. For now, all percentage
// radii will be relative to the width.
handle_overlapping_radii(&abs_bounds.size, &BorderRadii {
top_left: model::specified(border_style.border_top_left_radius,
abs_bounds.size.width),
top_right: model::specified(border_style.border_top_right_radius,
abs_bounds.size.width),
bottom_right: model::specified(border_style.border_bottom_right_radius,
abs_bounds.size.width),
bottom_left: model::specified(border_style.border_bottom_left_radius,
abs_bounds.size.width),
})
}
impl FragmentDisplayListBuilding for Fragment {
fn build_display_list_for_background_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion) {
// Adjust the clipping region as necessary to account for `border-radius`.
let border_radii = build_border_radius(absolute_bounds, style.get_border());
let mut clip = (*clip).clone();
if !border_radii.is_square() {
clip = clip.intersect_with_rounded_rect(absolute_bounds, &border_radii)
}
// FIXME: This causes a lot of background colors to be displayed when they are clearly not
// needed. We could use display list optimization to clean this up, but it still seems
// inefficient. What we really want is something like "nearest ancestor element that
// doesn't have a fragment".
let background_color = style.resolve_color(style.get_background().background_color);
display_list.push(DisplayItem::SolidColorClass(box SolidColorDisplayItem {
base: BaseDisplayItem::new(*absolute_bounds,
DisplayItemMetadata::new(self.node,
style,
Cursor::DefaultCursor),
clip.clone()),
color: background_color.to_gfx_color(),
}), level);
// The background image is painted on top of the background color.
// Implements background image, per spec:
// http://www.w3.org/TR/CSS21/colors.html#background
let background = style.get_background();
match background.background_image {
None => {}
Some(Image::LinearGradient(ref gradient)) => {
self.build_display_list_for_background_linear_gradient(display_list,
level,
absolute_bounds,
&clip,
gradient,
style)
}
Some(Image::Url(ref image_url)) => {
self.build_display_list_for_background_image(style,
display_list,
layout_context,
level,
absolute_bounds,
&clip,
image_url)
}
}
}
fn compute_background_image_size(&self,
style: &ComputedValues,
bounds: &Rect<Au>,
image: &png::Image)
-> Size2D<Au> {
// If `image_aspect_ratio` < `bounds_aspect_ratio`, the image is tall; otherwise, it is
// wide.
let image_aspect_ratio = (image.width as f64) / (image.height as f64);
let bounds_aspect_ratio = bounds.size.width.to_subpx() / bounds.size.height.to_subpx();
let intrinsic_size = Size2D(Au::from_px(image.width as isize),
Au::from_px(image.height as isize));
match (style.get_background().background_size.clone(),
image_aspect_ratio < bounds_aspect_ratio) {
(background_size::T::Contain, false) | (background_size::T::Cover, true) => {
Size2D(bounds.size.width,
Au::from_frac_px(bounds.size.width.to_subpx() / image_aspect_ratio))
}
(background_size::T::Contain, true) | (background_size::T::Cover, false) => {
Size2D(Au::from_frac_px(bounds.size.height.to_subpx() * image_aspect_ratio),
bounds.size.height)
}
(background_size::T::Explicit(background_size::ExplicitSize {
width,
height: LengthOrPercentageOrAuto::Auto,
}), _) => {
let width = MaybeAuto::from_style(width, bounds.size.width)
.specified_or_default(intrinsic_size.width);
Size2D(width, Au::from_frac_px(width.to_subpx() / image_aspect_ratio))
}
(background_size::T::Explicit(background_size::ExplicitSize {
width: LengthOrPercentageOrAuto::Auto,
height
}), _) => {
let height = MaybeAuto::from_style(height, bounds.size.height)
.specified_or_default(intrinsic_size.height);
Size2D(Au::from_frac_px(height.to_subpx() * image_aspect_ratio), height)
}
(background_size::T::Explicit(background_size::ExplicitSize {
width,
height
}), _) => {
Size2D(MaybeAuto::from_style(width, bounds.size.width)
.specified_or_default(intrinsic_size.width),
MaybeAuto::from_style(height, bounds.size.height)
.specified_or_default(intrinsic_size.height))
}
}
}
fn build_display_list_for_background_image(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion,
image_url: &Url) {
let background = style.get_background();
let mut holder = ImageHolder::new(image_url.clone(),
layout_context.shared.image_cache.clone());
let image = match holder.get_image(self.node.to_untrusted_node_address()) {
None => {
// No image data at all? Do nothing.
//
// TODO: Add some kind of placeholder background image.
debug!("(building display list) no background image :(");
return
}
Some(image) => image,
};
debug!("(building display list) building background image");
// Use `background-size` to get the size.
let mut bounds = *absolute_bounds;
let image_size = self.compute_background_image_size(style, &bounds, &*image);
// Clip.
//
// TODO: Check the bounds to see if a clip item is actually required.
let clip = clip.clone().intersect_rect(&bounds);
// Use `background-attachment` to get the initial virtual origin
let (virtual_origin_x, virtual_origin_y) = match background.background_attachment {
background_attachment::T::scroll => {
(absolute_bounds.origin.x, absolute_bounds.origin.y)
}
background_attachment::T::fixed => {
(Au(0), Au(0))
}
};
// Use `background-position` to get the offset.
let horizontal_position = model::specified(background.background_position.horizontal,
bounds.size.width - image_size.width);
let vertical_position = model::specified(background.background_position.vertical,
bounds.size.height - image_size.height);
let abs_x = virtual_origin_x + horizontal_position;
let abs_y = virtual_origin_y + vertical_position;
// Adjust origin and size based on background-repeat
match background.background_repeat {
background_repeat::T::no_repeat => {
bounds.origin.x = abs_x;
bounds.origin.y = abs_y;
bounds.size.width = image_size.width;
bounds.size.height = image_size.height;
}
background_repeat::T::repeat_x => {
bounds.origin.y = abs_y;
bounds.size.height = image_size.height;
ImageFragmentInfo::tile_image(&mut bounds.origin.x,
&mut bounds.size.width,
abs_x,
image_size.width.to_nearest_px() as u32);
}
background_repeat::T::repeat_y => {
bounds.origin.x = abs_x;
bounds.size.width = image_size.width;
ImageFragmentInfo::tile_image(&mut bounds.origin.y,
&mut bounds.size.height,
abs_y,
image_size.height.to_nearest_px() as u32);
}
background_repeat::T::repeat => {
ImageFragmentInfo::tile_image(&mut bounds.origin.x,
&mut bounds.size.width,
abs_x,
image_size.width.to_nearest_px() as u32);
ImageFragmentInfo::tile_image(&mut bounds.origin.y,
&mut bounds.size.height,
abs_y,
image_size.height.to_nearest_px() as u32);
}
};
// Create the image display item.
display_list.push(DisplayItem::ImageClass(box ImageDisplayItem {
base: BaseDisplayItem::new(bounds,
DisplayItemMetadata::new(self.node,
style,
Cursor::DefaultCursor),
clip),
image: image.clone(),
stretch_size: Size2D(image_size.width, image_size.height),
image_rendering: style.get_effects().image_rendering.clone(),
}), level);
}
fn build_display_list_for_background_linear_gradient(&self,
display_list: &mut DisplayList,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion,
gradient: &LinearGradient,
style: &ComputedValues) {
let clip = clip.clone().intersect_rect(absolute_bounds);
// This is the distance between the center and the ending point; i.e. half of the distance
// between the starting point and the ending point.
let delta = match gradient.angle_or_corner {
AngleOrCorner::Angle(angle) => {
Point2D(Au((angle.radians().sin() *
absolute_bounds.size.width.to_f64().unwrap() / 2.0) as i32),
Au((-angle.radians().cos() *
absolute_bounds.size.height.to_f64().unwrap() / 2.0) as i32))
}
AngleOrCorner::Corner(horizontal, vertical) => {
let x_factor = match horizontal {
HorizontalDirection::Left => -1,
HorizontalDirection::Right => 1,
};
let y_factor = match vertical {
VerticalDirection::Top => -1,
VerticalDirection::Bottom => 1,
};
Point2D(Au(x_factor * absolute_bounds.size.width.to_i32().unwrap() / 2),
Au(y_factor * absolute_bounds.size.height.to_i32().unwrap() / 2))
}
};
// This is the length of the gradient line.
let length = Au((delta.x.to_f64().unwrap() * 2.0).hypot(delta.y.to_f64().unwrap() * 2.0)
as i32);
// Determine the position of each stop per CSS-IMAGES § 3.4.
//
// FIXME(#3908, pcwalton): Make sure later stops can't be behind earlier stops.
let (mut stops, mut stop_run) = (Vec::new(), None);
for (i, stop) in gradient.stops.iter().enumerate() {
let offset = match stop.position {
None => {
if stop_run.is_none() {
// Initialize a new stop run.
let start_offset = if i == 0 {
0.0
} else {
// `unwrap()` here should never fail because this is the beginning of
// a stop run, which is always bounded by a length or percentage.
position_to_offset(gradient.stops[i - 1].position.unwrap(), length)
};
let (end_index, end_offset) =
match gradient.stops[i..]
.iter()
.enumerate()
.find(|&(_, ref stop)| stop.position.is_some()) {
None => (gradient.stops.len() - 1, 1.0),
Some((end_index, end_stop)) => {
// `unwrap()` here should never fail because this is the end of
// a stop run, which is always bounded by a length or
// percentage.
(end_index,
position_to_offset(end_stop.position.unwrap(), length))
}
};
stop_run = Some(StopRun {
start_offset: start_offset,
end_offset: end_offset,
start_index: i,
stop_count: end_index - i,
})
}
let stop_run = stop_run.unwrap();
let stop_run_length = stop_run.end_offset - stop_run.start_offset;
if stop_run.stop_count == 0 {
stop_run.end_offset
} else {
stop_run.start_offset +
stop_run_length * (i - stop_run.start_index) as f32 /
(stop_run.stop_count as f32)
}
}
Some(position) => {
stop_run = None;
position_to_offset(position, length)
}
};
stops.push(GradientStop {
offset: offset,
color: style.resolve_color(stop.color).to_gfx_color()
})
}
let center = Point2D(absolute_bounds.origin.x + absolute_bounds.size.width / 2,
absolute_bounds.origin.y + absolute_bounds.size.height / 2);
let gradient_display_item = DisplayItem::GradientClass(box GradientDisplayItem {
base: BaseDisplayItem::new(*absolute_bounds,
DisplayItemMetadata::new(self.node,
style,
Cursor::DefaultCursor),
clip),
start_point: center - delta,
end_point: center + delta,
stops: stops,
});
display_list.push(gradient_display_item, level)
}
fn build_display_list_for_box_shadow_if_applicable(&self,
style: &ComputedValues,
list: &mut DisplayList,
_layout_context: &LayoutContext,
level: StackingLevel,
absolute_bounds: &Rect<Au>,
clip: &ClippingRegion) {
// NB: According to CSS-BACKGROUNDS, box shadows render in *reverse* order (front to back).
for box_shadow in style.get_effects().box_shadow.iter().rev() {
let bounds = shadow_bounds(&absolute_bounds.translate(&Point2D(box_shadow.offset_x,
box_shadow.offset_y)),
box_shadow.blur_radius,
box_shadow.spread_radius);
list.push(DisplayItem::BoxShadowClass(box BoxShadowDisplayItem {
base: BaseDisplayItem::new(bounds,
DisplayItemMetadata::new(self.node,
style,
Cursor::DefaultCursor),
(*clip).clone()),
box_bounds: *absolute_bounds,
color: style.resolve_color(box_shadow.color).to_gfx_color(),
offset: Point2D(box_shadow.offset_x, box_shadow.offset_y),
blur_radius: box_shadow.blur_radius,
spread_radius: box_shadow.spread_radius,
clip_mode: if box_shadow.inset {
BoxShadowClipMode::Inset
} else {
BoxShadowClipMode::Outset
},
}), level);
}
}
fn build_display_list_for_borders_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
abs_bounds: &Rect<Au>,
level: StackingLevel,
clip: &ClippingRegion) {
let border = style.logical_border_width();
if border.is_zero() {
return
}
let top_color = style.resolve_color(style.get_border().border_top_color);
let right_color = style.resolve_color(style.get_border().border_right_color);
let bottom_color = style.resolve_color(style.get_border().border_bottom_color);
let left_color = style.resolve_color(style.get_border().border_left_color);
// Append the border to the display list.
display_list.push(DisplayItem::BorderClass(box BorderDisplayItem {
base: BaseDisplayItem::new(*abs_bounds,
DisplayItemMetadata::new(self.node, style, Cursor::DefaultCursor),
(*clip).clone()),
border_widths: border.to_physical(style.writing_mode),
color: SideOffsets2D::new(top_color.to_gfx_color(),
right_color.to_gfx_color(),
bottom_color.to_gfx_color(),
left_color.to_gfx_color()),
style: SideOffsets2D::new(style.get_border().border_top_style,
style.get_border().border_right_style,
style.get_border().border_bottom_style,
style.get_border().border_left_style),
radius: build_border_radius(abs_bounds, style.get_border()),
}), level);
}
fn build_display_list_for_outline_if_applicable(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
bounds: &Rect<Au>,
clip: &ClippingRegion) {
let width = style.get_outline().outline_width;
if width == Au(0) {
return
}
let outline_style = style.get_outline().outline_style;
if outline_style == border_style::T::none {
return
}
// Outlines are not accounted for in the dimensions of the border box, so adjust the
// absolute bounds.
let mut bounds = *bounds;
let offset = width + style.get_outline().outline_offset;
bounds.origin.x = bounds.origin.x - offset;
bounds.origin.y = bounds.origin.y - offset;
bounds.size.width = bounds.size.width + offset + offset;
bounds.size.height = bounds.size.height + offset + offset;
// Append the outline to the display list.
let color = style.resolve_color(style.get_outline().outline_color).to_gfx_color();
display_list.outlines.push_back(DisplayItem::BorderClass(box BorderDisplayItem {
base: BaseDisplayItem::new(bounds,
DisplayItemMetadata::new(self.node, style, Cursor::DefaultCursor),
(*clip).clone()),
border_widths: SideOffsets2D::new_all_same(width),
color: SideOffsets2D::new_all_same(color),
style: SideOffsets2D::new_all_same(outline_style),
radius: Default::default(),
}))
}
fn build_debug_borders_around_text_fragments(&self,
style: &ComputedValues,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
stacking_relative_content_box: &Rect<Au>,
text_fragment: &ScannedTextFragmentInfo,
clip: &ClippingRegion) {
// FIXME(pcwalton, #2795): Get the real container size.
let container_size = Size2D::zero();
// Compute the text fragment bounds and draw a border surrounding them.
display_list.content.push_back(DisplayItem::BorderClass(box BorderDisplayItem {
base: BaseDisplayItem::new(*stacking_relative_border_box,
DisplayItemMetadata::new(self.node, style, Cursor::DefaultCursor),
(*clip).clone()),
border_widths: SideOffsets2D::new_all_same(Au::from_px(1)),
color: SideOffsets2D::new_all_same(color::rgb(0, 0, 200)),
style: SideOffsets2D::new_all_same(border_style::T::solid),
radius: Default::default(),
}));
// Draw a rectangle representing the baselines.
let mut baseline = LogicalRect::from_physical(self.style.writing_mode,
*stacking_relative_content_box,
container_size);
baseline.start.b = baseline.start.b + text_fragment.run.ascent();
baseline.size.block = Au(0);
let baseline = baseline.to_physical(self.style.writing_mode, container_size);
let line_display_item = box LineDisplayItem {
base: BaseDisplayItem::new(baseline,
DisplayItemMetadata::new(self.node, style, Cursor::DefaultCursor),
(*clip).clone()),
color: color::rgb(0, 200, 0),
style: border_style::T::dashed,
};
display_list.content.push_back(DisplayItem::LineClass(line_display_item));
}
fn build_debug_borders_around_fragment(&self,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
clip: &ClippingRegion) {
// This prints a debug border around the border of this fragment.
display_list.content.push_back(DisplayItem::BorderClass(box BorderDisplayItem {
base: BaseDisplayItem::new(*stacking_relative_border_box,
DisplayItemMetadata::new(self.node,
&*self.style,
Cursor::DefaultCursor),
(*clip).clone()),
border_widths: SideOffsets2D::new_all_same(Au::from_px(1)),
color: SideOffsets2D::new_all_same(color::rgb(0, 0, 200)),
style: SideOffsets2D::new_all_same(border_style::T::solid),
radius: Default::default(),
}));
}
fn calculate_style_specified_clip(&self,
parent_clip: &ClippingRegion,
stacking_relative_border_box: &Rect<Au>)
-> ClippingRegion {
// Account for `clip` per CSS 2.1 § 11.1.2.
let style_clip_rect = match (self.style().get_box().position,
self.style().get_effects().clip) {
(position::T::absolute, Some(style_clip_rect)) => style_clip_rect,
_ => return (*parent_clip).clone(),
};
// FIXME(pcwalton, #2795): Get the real container size.
let clip_origin = Point2D(stacking_relative_border_box.origin.x + style_clip_rect.left,
stacking_relative_border_box.origin.y + style_clip_rect.top);
let right = style_clip_rect.right.unwrap_or(stacking_relative_border_box.size.width);
let bottom = style_clip_rect.bottom.unwrap_or(stacking_relative_border_box.size.height);
let clip_size = Size2D(right - clip_origin.x, bottom - clip_origin.y);
(*parent_clip).clone().intersect_rect(&Rect(clip_origin, clip_size))
}
fn build_display_list(&mut self,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
stacking_relative_flow_origin: &Point2D<Au>,
relative_containing_block_size: &LogicalSize<Au>,
relative_containing_block_mode: WritingMode,
background_and_border_level: BackgroundAndBorderLevel,
clip: &ClippingRegion) {
// Compute the fragment position relative to the parent stacking context. If the fragment
// itself establishes a stacking context, then the origin of its position will be (0, 0)
// for the purposes of this computation.
let stacking_relative_border_box =
self.stacking_relative_border_box(stacking_relative_flow_origin,
relative_containing_block_size,
relative_containing_block_mode,
CoordinateSystem::Own);
debug!("Fragment::build_display_list at rel={:?}, abs={:?}, dirty={:?}, flow origin={:?}: \
{:?}",
self.border_box,
stacking_relative_border_box,
layout_context.shared.dirty,
stacking_relative_flow_origin,
self);
if self.style().get_inheritedbox().visibility != visibility::T::visible {
return
}
if !stacking_relative_border_box.intersects(&layout_context.shared.dirty) {
debug!("Fragment::build_display_list: Did not intersect...");
return
}
// Calculate the clip rect. If there's nothing to render at all, don't even construct
// display list items.
let clip = self.calculate_style_specified_clip(clip, &stacking_relative_border_box);
if !clip.might_intersect_rect(&stacking_relative_border_box) {
return;
}
debug!("Fragment::build_display_list: intersected. Adding display item...");
if self.is_primary_fragment() {
let level =
StackingLevel::from_background_and_border_level(background_and_border_level);
// Add shadows, background, borders, and outlines, if applicable.
if let Some(ref inline_context) = self.inline_context {
for style in inline_context.styles.iter().rev() {
self.build_display_list_for_box_shadow_if_applicable(
&**style,
display_list,
layout_context,
level,
&stacking_relative_border_box,
&clip);
self.build_display_list_for_background_if_applicable(
&**style,
display_list,
layout_context,
level,
&stacking_relative_border_box,
&clip);
self.build_display_list_for_borders_if_applicable(
&**style,
display_list,
&stacking_relative_border_box,
level,
&clip);
self.build_display_list_for_outline_if_applicable(
&**style,
display_list,
&stacking_relative_border_box,
&clip);
}
}
if !self.is_scanned_text_fragment() {
self.build_display_list_for_box_shadow_if_applicable(&*self.style,
display_list,
layout_context,
level,
&stacking_relative_border_box,
&clip);
self.build_display_list_for_background_if_applicable(&*self.style,
display_list,
layout_context,
level,
&stacking_relative_border_box,
&clip);
self.build_display_list_for_borders_if_applicable(&*self.style,
display_list,
&stacking_relative_border_box,
level,
&clip);
self.build_display_list_for_outline_if_applicable(&*self.style,
display_list,
&stacking_relative_border_box,
&clip);
}
}
// Create special per-fragment-type display items.
self.build_fragment_type_specific_display_items(display_list,
&stacking_relative_border_box,
&clip);
if opts::get().show_debug_fragment_borders {
self.build_debug_borders_around_fragment(display_list,
&stacking_relative_border_box,
&clip)
}
// If this is an iframe, then send its position and size up to the constellation.
//
// FIXME(pcwalton): Doing this during display list construction seems potentially
// problematic if iframes are outside the area we're computing the display list for, since
// they won't be able to reflow at all until the user scrolls to them. Perhaps we should
// separate this into two parts: first we should send the size only to the constellation
// once that's computed during assign-block-sizes, and second we should should send the
// origin to the constellation here during display list construction. This should work
// because layout for the iframe only needs to know size, and origin is only relevant if
// the iframe is actually going to be displayed.
if let SpecificFragmentInfo::Iframe(ref iframe_fragment) = self.specific {
self.finalize_position_and_size_of_iframe(&**iframe_fragment,
stacking_relative_border_box.origin,
layout_context)
}
}
fn build_fragment_type_specific_display_items(&mut self,
display_list: &mut DisplayList,
stacking_relative_border_box: &Rect<Au>,
clip: &ClippingRegion) {
// Compute the context box position relative to the parent stacking context.
let stacking_relative_content_box =
self.stacking_relative_content_box(stacking_relative_border_box);
match self.specific {
SpecificFragmentInfo::ScannedText(ref text_fragment) => {
// Create items for shadows.
//
// NB: According to CSS-BACKGROUNDS, text shadows render in *reverse* order (front
// to back).
let text_color = self.style().get_color().color;
for text_shadow in self.style.get_effects().text_shadow.0.iter().rev() {
let offset = &Point2D(text_shadow.offset_x, text_shadow.offset_y);
let color = self.style().resolve_color(text_shadow.color);
self.build_display_list_for_text_fragment(display_list,
&**text_fragment,
color,
&stacking_relative_content_box,
Some(text_shadow.blur_radius),
offset,
clip);
}
// Create the main text display item.
self.build_display_list_for_text_fragment(display_list,
&**text_fragment,
text_color,
&stacking_relative_content_box,
None,
&Point2D(Au(0), Au(0)),
clip);
if opts::get().show_debug_fragment_borders {
self.build_debug_borders_around_text_fragments(self.style(),
display_list,
stacking_relative_border_box,
&stacking_relative_content_box,
&**text_fragment,
clip)
}
}
SpecificFragmentInfo::Generic |
SpecificFragmentInfo::GeneratedContent(..) |
SpecificFragmentInfo::Iframe(..) |
SpecificFragmentInfo::Table |
SpecificFragmentInfo::TableCell |
SpecificFragmentInfo::TableRow |
SpecificFragmentInfo::TableWrapper |
SpecificFragmentInfo::InlineBlock(_) |
SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
if opts::get().show_debug_fragment_borders {
self.build_debug_borders_around_fragment(display_list,
stacking_relative_border_box,
clip);
}
}
SpecificFragmentInfo::Image(ref mut image_fragment) => {
let image_ref = &mut image_fragment.image;
if let Some(image) = image_ref.get_image(self.node.to_untrusted_node_address()) {
debug!("(building display list) building image fragment");
// Place the image into the display list.
display_list.content.push_back(DisplayItem::ImageClass(box ImageDisplayItem {
base: BaseDisplayItem::new(stacking_relative_content_box,
DisplayItemMetadata::new(self.node,
&*self.style,
Cursor::DefaultCursor),
(*clip).clone()),
image: image.clone(),
stretch_size: stacking_relative_content_box.size,
image_rendering: self.style.get_effects().image_rendering.clone(),
}));
} else {
// No image data at all? Do nothing.
//
// TODO: Add some kind of placeholder image.
debug!("(building display list) no image :(");
}
}
SpecificFragmentInfo::Canvas(ref canvas_fragment_info) => {
let width = canvas_fragment_info.replaced_image_fragment_info
.computed_inline_size.map_or(0, |w| to_px(w) as usize);
let height = canvas_fragment_info.replaced_image_fragment_info
.computed_block_size.map_or(0, |h| to_px(h) as usize);
let (sender, receiver) = channel::<Vec<u8>>();
let canvas_data = match canvas_fragment_info.renderer {
Some(ref renderer) => {
renderer.lock().unwrap().send(SendPixelContents(sender)).unwrap();
receiver.recv().unwrap()
},
None => repeat(0xFFu8).take(width * height * 4).collect(),
};
let canvas_display_item = box ImageDisplayItem {
base: BaseDisplayItem::new(stacking_relative_content_box,
DisplayItemMetadata::new(self.node,
&*self.style,
Cursor::DefaultCursor),
(*clip).clone()),
image: Arc::new(png::Image {
width: width as u32,
height: height as u32,
pixels: PixelsByColorType::RGBA8(canvas_data),
}),
stretch_size: stacking_relative_content_box.size,
image_rendering: image_rendering::T::Auto,
};
display_list.content.push_back(DisplayItem::ImageClass(canvas_display_item));
}
SpecificFragmentInfo::UnscannedText(_) => {
panic!("Shouldn't see unscanned fragments here.")
}
SpecificFragmentInfo::TableColumn(_) => {
panic!("Shouldn't see table column fragments here.")
}
}
}
#[inline(never)]
fn finalize_position_and_size_of_iframe(&self,
iframe_fragment: &IframeFragmentInfo,
offset: Point2D<Au>,
layout_context: &LayoutContext) {
let border_padding = (self.border_padding).to_physical(self.style.writing_mode);
let content_size = self.content_box().size.to_physical(self.style.writing_mode);
let iframe_rect = Rect(Point2D(geometry::to_frac_px(offset.x + border_padding.left) as f32,
geometry::to_frac_px(offset.y + border_padding.top) as f32),
Size2D(geometry::to_frac_px(content_size.width) as f32,
geometry::to_frac_px(content_size.height) as f32));
debug!("finalizing position and size of iframe for {:?},{:?}",
iframe_fragment.pipeline_id,
iframe_fragment.subpage_id);
let ConstellationChan(ref chan) = layout_context.shared.constellation_chan;
chan.send(ConstellationMsg::FrameRect(iframe_fragment.pipeline_id,
iframe_fragment.subpage_id,
iframe_rect)).unwrap();
}
fn clipping_region_for_children(&self,
current_clip: &ClippingRegion,
stacking_relative_border_box: &Rect<Au>)
-> ClippingRegion {
// Don't clip if we're text.
if self.is_scanned_text_fragment() {
return (*current_clip).clone()
}
// Account for style-specified `clip`.
let mut current_clip = self.calculate_style_specified_clip(current_clip,
stacking_relative_border_box);
// Clip according to the values of `overflow-x` and `overflow-y`.
//
// TODO(pcwalton): Support scrolling.
// FIXME(pcwalton): This may be more complex than it needs to be, since it seems to be
// impossible with the computed value rules as they are to have `overflow-x: visible` with
// `overflow-y: <scrolling>` or vice versa!
match self.style.get_box().overflow_x {
overflow_x::T::hidden | overflow_x::T::auto | overflow_x::T::scroll => {
let mut bounds = current_clip.bounding_rect();
let max_x = cmp::min(bounds.max_x(), stacking_relative_border_box.max_x());
bounds.origin.x = cmp::max(bounds.origin.x, stacking_relative_border_box.origin.x);
bounds.size.width = max_x - bounds.origin.x;
current_clip = current_clip.intersect_rect(&bounds)
}
_ => {}
}
match self.style.get_box().overflow_y.0 {
overflow_x::T::hidden | overflow_x::T::auto | overflow_x::T::scroll => {
let mut bounds = current_clip.bounding_rect();
let max_y = cmp::min(bounds.max_y(), stacking_relative_border_box.max_y());
bounds.origin.y = cmp::max(bounds.origin.y, stacking_relative_border_box.origin.y);
bounds.size.height = max_y - bounds.origin.y;
current_clip = current_clip.intersect_rect(&bounds)
}
_ => {}
}
current_clip
}
fn build_display_list_for_text_fragment(&self,
display_list: &mut DisplayList,
text_fragment: &ScannedTextFragmentInfo,
text_color: RGBA,
stacking_relative_content_box: &Rect<Au>,
shadow_blur_radius: Option<Au>,
offset: &Point2D<Au>,
clip: &ClippingRegion) {
// Determine the orientation and cursor to use.
let (orientation, cursor) = if self.style.writing_mode.is_vertical() {
if self.style.writing_mode.is_sideways_left() {
(TextOrientation::SidewaysLeft, Cursor::VerticalTextCursor)
} else {
(TextOrientation::SidewaysRight, Cursor::VerticalTextCursor)
}
} else {
(TextOrientation::Upright, Cursor::TextCursor)
};
// Compute location of the baseline.
//
// FIXME(pcwalton): Get the real container size.
let container_size = Size2D::zero();
let metrics = &text_fragment.run.font_metrics;
let stacking_relative_content_box = stacking_relative_content_box.translate(offset);
let baseline_origin = stacking_relative_content_box.origin +
LogicalPoint::new(self.style.writing_mode,
Au(0),
metrics.ascent).to_physical(self.style.writing_mode,
container_size);
// Create the text display item.
display_list.content.push_back(DisplayItem::TextClass(box TextDisplayItem {
base: BaseDisplayItem::new(stacking_relative_content_box,
DisplayItemMetadata::new(self.node, self.style(), cursor),
(*clip).clone()),
text_run: text_fragment.run.clone(),
range: text_fragment.range,
text_color: text_color.to_gfx_color(),
orientation: orientation,
baseline_origin: baseline_origin,
blur_radius: shadow_blur_radius.unwrap_or(Au(0)),
}));
// Create display items for text decorations.
let mut text_decorations = self.style()
.get_inheritedtext()
._servo_text_decorations_in_effect;
if shadow_blur_radius.is_some() {
// If we're painting a shadow, paint the decorations the same color as the shadow.
text_decorations.underline = text_decorations.underline.map(|_| text_color);
text_decorations.overline = text_decorations.overline.map(|_| text_color);
text_decorations.line_through = text_decorations.line_through.map(|_| text_color);
}
let stacking_relative_content_box =
LogicalRect::from_physical(self.style.writing_mode,
stacking_relative_content_box,
container_size);
if let Some(ref underline_color) = text_decorations.underline {
let mut stacking_relative_box = stacking_relative_content_box;
stacking_relative_box.start.b = stacking_relative_content_box.start.b +
metrics.ascent - metrics.underline_offset;
stacking_relative_box.size.block = metrics.underline_size;
self.build_display_list_for_text_decoration(display_list,
underline_color,
&stacking_relative_box,
clip,
shadow_blur_radius.unwrap_or(Au(0)))
}
if let Some(ref overline_color) = text_decorations.overline {
let mut stacking_relative_box = stacking_relative_content_box;
stacking_relative_box.size.block = metrics.underline_size;
self.build_display_list_for_text_decoration(display_list,
overline_color,
&stacking_relative_box,
clip,
shadow_blur_radius.unwrap_or(Au(0)))
}
if let Some(ref line_through_color) = text_decorations.line_through {
let mut stacking_relative_box = stacking_relative_content_box;
stacking_relative_box.start.b = stacking_relative_box.start.b + metrics.ascent -
metrics.strikeout_offset;
stacking_relative_box.size.block = metrics.strikeout_size;
self.build_display_list_for_text_decoration(display_list,
line_through_color,
&stacking_relative_box,
clip,
shadow_blur_radius.unwrap_or(Au(0)))
}
}
fn build_display_list_for_text_decoration(&self,
display_list: &mut DisplayList,
color: &RGBA,
stacking_relative_box: &LogicalRect<Au>,
clip: &ClippingRegion,
blur_radius: Au) {
// Perhaps surprisingly, text decorations are box shadows. This is because they may need
// to have blur in the case of `text-shadow`, and this doesn't hurt performance because box
// shadows are optimized into essentially solid colors if there is no need for the blur.
//
// FIXME(pcwalton, #2795): Get the real container size.
let container_size = Size2D::zero();
let stacking_relative_box = stacking_relative_box.to_physical(self.style.writing_mode,
container_size);
let metadata = DisplayItemMetadata::new(self.node, &*self.style, Cursor::DefaultCursor);
display_list.content.push_back(DisplayItem::BoxShadowClass(box BoxShadowDisplayItem {
base: BaseDisplayItem::new(shadow_bounds(&stacking_relative_box, blur_radius, Au(0)),
metadata,
(*clip).clone()),
box_bounds: stacking_relative_box,
color: color.to_gfx_color(),
offset: ZERO_POINT,
blur_radius: blur_radius,
spread_radius: Au(0),
clip_mode: BoxShadowClipMode::None,
}))
}
}
pub trait BlockFlowDisplayListBuilding {
fn build_display_list_for_block_base(&mut self,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
background_border_level: BackgroundAndBorderLevel);
fn build_display_list_for_static_block(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext,
background_border_level: BackgroundAndBorderLevel);
fn build_display_list_for_absolutely_positioned_block(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext);
fn build_display_list_for_floating_block(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext);
fn build_display_list_for_block(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext);
fn create_stacking_context(&self,
display_list: Box<DisplayList>,
layer: Option<Arc<PaintLayer>>)
-> Arc<StackingContext>;
}
impl BlockFlowDisplayListBuilding for BlockFlow {
fn build_display_list_for_block_base(&mut self,
display_list: &mut DisplayList,
layout_context: &LayoutContext,
background_border_level: BackgroundAndBorderLevel) {
// Add the box that starts the block context.
let clip = if self.fragment.establishes_stacking_context() {
self.base.clip.translate(&-self.base.stacking_relative_position)
} else {
self.base.clip.clone()
};
self.fragment.build_display_list(display_list,
layout_context,
&self.base.stacking_relative_position,
&self.base
.absolute_position_info
.relative_containing_block_size,
self.base
.absolute_position_info
.relative_containing_block_mode,
background_border_level,
&clip);
// Add children.
for kid in self.base.children.iter_mut() {
flow::mut_base(kid).display_list_building_result.add_to(display_list);
}
self.base.build_display_items_for_debugging_tint(display_list, self.fragment.node);
}
fn build_display_list_for_static_block(&mut self,
mut display_list: Box<DisplayList>,
layout_context: &LayoutContext,
background_border_level: BackgroundAndBorderLevel) {
self.build_display_list_for_block_base(&mut *display_list,
layout_context,
background_border_level);
self.base.display_list_building_result = if self.fragment.establishes_stacking_context() {
DisplayListBuildingResult::StackingContext(self.create_stacking_context(display_list,
None))
} else {
DisplayListBuildingResult::Normal(display_list)
}
}
fn build_display_list_for_absolutely_positioned_block(&mut self,
mut display_list: Box<DisplayList>,
layout_context: &LayoutContext) {
self.build_display_list_for_block_base(&mut *display_list,
layout_context,
BackgroundAndBorderLevel::RootOfStackingContext);
if !self.base.absolute_position_info.layers_needed_for_positioned_flows &&
!self.base.flags.contains(NEEDS_LAYER) {
// We didn't need a layer.
self.base.display_list_building_result =
DisplayListBuildingResult::StackingContext(self.create_stacking_context(
display_list,
None));
return
}
// If we got here, then we need a new layer.
let scroll_policy = if self.is_fixed() {
ScrollPolicy::FixedPosition
} else {
ScrollPolicy::Scrollable
};
let transparent = color::rgba(1.0, 1.0, 1.0, 0.0);
let stacking_context =
self.create_stacking_context(display_list,
Some(Arc::new(PaintLayer::new(self.layer_id(0),
transparent,
scroll_policy))));
self.base.display_list_building_result =
DisplayListBuildingResult::StackingContext(stacking_context)
}
fn build_display_list_for_floating_block(&mut self,
mut display_list: Box<DisplayList>,
layout_context: &LayoutContext) {
self.build_display_list_for_block_base(&mut *display_list,
layout_context,
BackgroundAndBorderLevel::RootOfStackingContext);
display_list.form_float_pseudo_stacking_context();
self.base.display_list_building_result = if self.fragment.establishes_stacking_context() {
DisplayListBuildingResult::StackingContext(self.create_stacking_context(display_list,
None))
} else {
DisplayListBuildingResult::Normal(display_list)
}
}
fn build_display_list_for_block(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext) {
if self.base.flags.is_float() {
// TODO(#2009, pcwalton): This is a pseudo-stacking context. We need to merge `z-index:
// auto` kids into the parent stacking context, when that is supported.
self.build_display_list_for_floating_block(display_list, layout_context);
} else if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
self.build_display_list_for_absolutely_positioned_block(display_list, layout_context);
} else {
self.build_display_list_for_static_block(display_list,
layout_context,
BackgroundAndBorderLevel::Block);
}
}
fn create_stacking_context(&self,
display_list: Box<DisplayList>,
layer: Option<Arc<PaintLayer>>)
-> Arc<StackingContext> {
debug_assert!(self.fragment.establishes_stacking_context());
let border_box = self.fragment
.stacking_relative_border_box(&self.base.stacking_relative_position,
&self.base
.absolute_position_info
.relative_containing_block_size,
self.base
.absolute_position_info
.relative_containing_block_mode,
CoordinateSystem::Parent);
let transform_origin = self.fragment.style().get_effects().transform_origin;
let transform_origin =
Point2D(model::specified(transform_origin.horizontal,
border_box.size.width).to_frac32_px(),
model::specified(transform_origin.vertical,
border_box.size.height).to_frac32_px());
let transform = self.fragment
.style()
.get_effects()
.transform
.unwrap_or(ComputedMatrix::identity())
.to_gfx_matrix(&border_box.size);
let transform = Matrix2D::identity().translate(transform_origin.x, transform_origin.y)
.mul(&transform)
.translate(-transform_origin.x, -transform_origin.y);
// FIXME(pcwalton): Is this vertical-writing-direction-safe?
let margin = self.fragment.margin.to_physical(self.base.writing_mode);
let overflow = self.base.overflow.translate(&-Point2D(margin.left, Au(0)));
// Create the filter pipeline.
let effects = self.fragment.style().get_effects();
let mut filters = effects.filter.clone();
if effects.opacity != 1.0 {
filters.push(Filter::Opacity(effects.opacity))
}
Arc::new(StackingContext::new(display_list,
&border_box,
&overflow,
self.fragment.style().get_box().z_index.number_or_zero(),
&transform,
filters,
self.fragment.style().get_effects().mix_blend_mode,
layer))
}
}
pub trait InlineFlowDisplayListBuilding {
fn build_display_list_for_inline(&mut self, layout_context: &LayoutContext);
}
impl InlineFlowDisplayListBuilding for InlineFlow {
fn build_display_list_for_inline(&mut self, layout_context: &LayoutContext) {
// TODO(#228): Once we form lines and have their cached bounds, we can be smarter and
// not recurse on a line if nothing in it can intersect the dirty region.
debug!("Flow: building display list for {} inline fragments", self.fragments.len());
let mut display_list = box DisplayList::new();
for fragment in self.fragments.fragments.iter_mut() {
fragment.build_display_list(&mut *display_list,
layout_context,
&self.base.stacking_relative_position,
&self.base
.absolute_position_info
.relative_containing_block_size,
self.base
.absolute_position_info
.relative_containing_block_mode,
BackgroundAndBorderLevel::Content,
&self.base.clip);
match fragment.specific {
SpecificFragmentInfo::InlineBlock(ref mut block_flow) => {
let block_flow = &mut *block_flow.flow_ref;
flow::mut_base(block_flow).display_list_building_result
.add_to(&mut *display_list)
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut block_flow) => {
let block_flow = &mut *block_flow.flow_ref;
flow::mut_base(block_flow).display_list_building_result
.add_to(&mut *display_list)
}
_ => {}
}
}
if !self.fragments.fragments.is_empty() {
self.base.build_display_items_for_debugging_tint(&mut *display_list,
self.fragments.fragments[0].node);
}
self.base.display_list_building_result = DisplayListBuildingResult::Normal(display_list);
if opts::get().validate_display_list_geometry {
self.base.validate_display_list_geometry();
}
}
}
pub trait ListItemFlowDisplayListBuilding {
fn build_display_list_for_list_item(&mut self,
display_list: Box<DisplayList>,
layout_context: &LayoutContext);
}
impl ListItemFlowDisplayListBuilding for ListItemFlow {
fn build_display_list_for_list_item(&mut self,
mut display_list: Box<DisplayList>,
layout_context: &LayoutContext) {
// Draw the marker, if applicable.
if let Some(ref mut marker) = self.marker {
marker.build_display_list(&mut *display_list,
layout_context,
&self.block_flow.base.stacking_relative_position,
&self.block_flow
.base
.absolute_position_info
.relative_containing_block_size,
self.block_flow
.base
.absolute_position_info
.relative_containing_block_mode,
BackgroundAndBorderLevel::Content,
&self.block_flow.base.clip);
}
// Draw the rest of the block.
self.block_flow.build_display_list_for_block(display_list, layout_context)
}
}
trait BaseFlowDisplayListBuilding {
fn build_display_items_for_debugging_tint(&self,
display_list: &mut DisplayList,
node: OpaqueNode);
}
impl BaseFlowDisplayListBuilding for BaseFlow {
fn build_display_items_for_debugging_tint(&self,
display_list: &mut DisplayList,
node: OpaqueNode) {
if !opts::get().show_debug_parallel_layout {
return
}
let thread_id = self.thread_id;
let stacking_context_relative_bounds =
Rect(self.stacking_relative_position,
self.position.size.to_physical(self.writing_mode));
let mut color = THREAD_TINT_COLORS[thread_id as usize % THREAD_TINT_COLORS.len()];
color.a = 1.0;
display_list.push(DisplayItem::BorderClass(box BorderDisplayItem {
base: BaseDisplayItem::new(stacking_context_relative_bounds.inflate(Au::from_px(2),
Au::from_px(2)),
DisplayItemMetadata {
node: node,
pointing: None,
},
self.clip.clone()),
border_widths: SideOffsets2D::new_all_same(Au::from_px(2)),
color: SideOffsets2D::new_all_same(color),
style: SideOffsets2D::new_all_same(border_style::T::solid),
radius: BorderRadii::all_same(Au(0)),
}), StackingLevel::Content);
}
}
// A helper data structure for gradients.
#[derive(Copy)]
struct StopRun {
start_offset: f32,
end_offset: f32,
start_index: usize,
stop_count: usize,
}
fn fmin(a: f32, b: f32) -> f32 {
if a < b {
a
} else {
b
}
}
fn position_to_offset(position: LengthOrPercentage, Au(total_length): Au) -> f32 {
match position {
LengthOrPercentage::Length(Au(length)) => fmin(1.0, (length as f32) / (total_length as f32)),
LengthOrPercentage::Percentage(percentage) => percentage as f32,
}
}
/// "Steps" as defined by CSS 2.1 § E.2.
#[derive(Clone, PartialEq, Debug, Copy)]
pub enum StackingLevel {
/// The border and backgrounds for the root of this stacking context: steps 1 and 2.
BackgroundAndBorders,
/// Borders and backgrounds for block-level descendants: step 4.
BlockBackgroundsAndBorders,
/// All other content.
Content,
}
impl StackingLevel {
#[inline]
pub fn from_background_and_border_level(level: BackgroundAndBorderLevel) -> StackingLevel {
match level {
BackgroundAndBorderLevel::RootOfStackingContext => StackingLevel::BackgroundAndBorders,
BackgroundAndBorderLevel::Block => StackingLevel::BlockBackgroundsAndBorders,
BackgroundAndBorderLevel::Content => StackingLevel::Content,
}
}
}
/// Which level to place backgrounds and borders in.
pub enum BackgroundAndBorderLevel {
RootOfStackingContext,
Block,
Content,
}
trait StackingContextConstruction {
/// Adds the given display item at the specified level to this display list.
fn push(&mut self, display_item: DisplayItem, level: StackingLevel);
}
impl StackingContextConstruction for DisplayList {
fn push(&mut self, display_item: DisplayItem, level: StackingLevel) {
match level {
StackingLevel::BackgroundAndBorders => {
self.background_and_borders.push_back(display_item)
}
StackingLevel::BlockBackgroundsAndBorders => {
self.block_backgrounds_and_borders.push_back(display_item)
}
StackingLevel::Content => self.content.push_back(display_item),
}
}
}
/// Adjusts `content_rect` as necessary for the given spread, and blur so that the resulting
/// bounding rect contains all of a shadow's ink.
fn shadow_bounds(content_rect: &Rect<Au>, blur_radius: Au, spread_radius: Au) -> Rect<Au> {
let inflation = spread_radius + blur_radius * BLUR_INFLATION_FACTOR;
content_rect.inflate(inflation, inflation)
}
/// Allows a CSS color to be converted into a graphics color.
pub trait ToGfxColor {
/// Converts a CSS color to a graphics color.
fn to_gfx_color(&self) -> Color;
}
impl ToGfxColor for RGBA {
fn to_gfx_color(&self) -> Color {
color::rgba(self.red, self.green, self.blue, self.alpha)
}
}
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