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Move calculation functions out of builder.rs

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This commit is contained in:
Pyfisch 2018-02-12 17:46:23 +01:00
parent 8d061118c4
commit 0d0f2abf12
2 changed files with 339 additions and 315 deletions
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292
components/layout/display_list/background.rs
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@ -2,7 +2,10 @@
* 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/. */
//! Calculations for CSS images and CSS backgrounds.
//! Calculations for CSS images, backgrounds and borders.
//!
//! * [CSS Images Module Level 3](https://drafts.csswg.org/css-images-3/)
//! * [CSS Backgrounds and Borders Module Level 3](https://drafts.csswg.org/css-backgrounds-3/)
#![deny(unsafe_code)]
@ -10,12 +13,16 @@
use app_units::Au;
use display_list::ToLayout;
use euclid::{Point2D, Size2D, Vector2D};
use gfx::display_list;
use model::MaybeAuto;
use euclid::{Point2D, Rect, SideOffsets2D, Size2D, Vector2D};
use gfx::display_list::{self, BorderDetails, WebRenderImageInfo};
use model::{self, MaybeAuto};
use style::computed_values::background_attachment::single_value::T as BackgroundAttachment;
use style::computed_values::background_clip::single_value::T as BackgroundClip;
use style::computed_values::background_origin::single_value::T as BackgroundOrigin;
use style::properties::style_structs::{self, Background};
use style::values::computed::{Angle, GradientItem};
use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto, Percentage};
use style::values::computed::Position;
use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
use style::values::computed::{NumberOrPercentage, Percentage, Position};
use style::values::computed::image::{EndingShape, LineDirection};
use style::values::generics::background::BackgroundSize;
use style::values::generics::image::{Circle, Ellipse, ShapeExtent};
@ -23,7 +30,8 @@ use style::values::generics::image::EndingShape as GenericEndingShape;
use style::values::generics::image::GradientItem as GenericGradientItem;
use style::values::specified::background::BackgroundRepeatKeyword;
use style::values::specified::position::{X, Y};
use webrender_api::{ExtendMode, GradientStop};
use webrender_api::{BorderRadius, BorderSide, BorderStyle, ColorF, ExtendMode, ImageBorder};
use webrender_api::{GradientStop, LayoutSize, NinePatchDescriptor, NormalBorder};
/// A helper data structure for gradients.
#[derive(Clone, Copy)]
@ -34,9 +42,51 @@ struct StopRun {
stop_count: usize,
}
/// Placment information for both image and gradient backgrounds.
#[derive(Clone, Copy, Debug)]
pub struct BackgroundPlacement {
/// Rendering bounds. The background will start in the uppper-left corner
/// and fill the whole area.
pub bounds: Rect<Au>,
/// Background tile size. Some backgrounds are repeated. These are the
/// dimensions of a single image of the background.
pub tile_size: Size2D<Au>,
/// Spacing between tiles. Some backgrounds are not repeated seamless
/// but have seams between them like tiles in real life.
pub tile_spacing: Size2D<Au>,
/// A clip area. While the background is rendered according to all the
/// measures above it is only shown within these bounds.
pub css_clip: Rect<Au>,
/// Whether or not the background is fixed to the viewport.
pub fixed: bool,
}
trait ResolvePercentage {
fn resolve(&self, length: u32) -> u32;
}
impl ResolvePercentage for NumberOrPercentage {
fn resolve(&self, length: u32) -> u32 {
match *self {
NumberOrPercentage::Percentage(p) => (p.0 * length as f32).round() as u32,
NumberOrPercentage::Number(n) => n.round() as u32,
}
}
}
/// Access element at index modulo the array length.
///
/// Obviously it does not work with empty arrays.
///
/// This is used for multiple layered background images.
/// See: https://drafts.csswg.org/css-backgrounds-3/#layering
pub fn get_cyclic<T>(arr: &[T], index: usize) -> &T {
&arr[index % arr.len()]
}
/// For a given area and an image compute how big the
/// image should be displayed on the background.
pub fn compute_background_image_size(
fn compute_background_image_size(
bg_size: BackgroundSize<LengthOrPercentageOrAuto>,
bounds_size: Size2D<Au>,
intrinsic_size: Option<Size2D<Au>>,
@ -99,6 +149,82 @@ pub fn compute_background_image_size(
}
}
/// Determines where to place an element background image or gradient.
///
/// Photos have their resolution as intrinsic size while gradients have
/// no intrinsic size.
pub fn compute_background_placement(
bg: &Background,
viewport_size: Size2D<Au>,
absolute_bounds: Rect<Au>,
intrinsic_size: Option<Size2D<Au>>,
border: SideOffsets2D<Au>,
border_padding: SideOffsets2D<Au>,
index: usize,
) -> BackgroundPlacement {
let bg_attachment = *get_cyclic(&bg.background_attachment.0, index);
let bg_clip = *get_cyclic(&bg.background_clip.0, index);
let bg_origin = *get_cyclic(&bg.background_origin.0, index);
let bg_position_x = get_cyclic(&bg.background_position_x.0, index);
let bg_position_y = get_cyclic(&bg.background_position_y.0, index);
let bg_repeat = get_cyclic(&bg.background_repeat.0, index);
let bg_size = *get_cyclic(&bg.background_size.0, index);
let css_clip = match bg_clip {
BackgroundClip::BorderBox => absolute_bounds,
BackgroundClip::PaddingBox => absolute_bounds.inner_rect(border),
BackgroundClip::ContentBox => absolute_bounds.inner_rect(border_padding),
};
let mut fixed = false;
let mut bounds = match bg_attachment {
BackgroundAttachment::Scroll => match bg_origin {
BackgroundOrigin::BorderBox => absolute_bounds,
BackgroundOrigin::PaddingBox => absolute_bounds.inner_rect(border),
BackgroundOrigin::ContentBox => absolute_bounds.inner_rect(border_padding),
},
BackgroundAttachment::Fixed => {
fixed = true;
Rect::new(Point2D::origin(), viewport_size)
},
};
let mut tile_size = compute_background_image_size(bg_size, bounds.size, intrinsic_size);
let mut tile_spacing = Size2D::zero();
let own_position = bounds.size - tile_size;
let pos_x = bg_position_x.to_used_value(own_position.width);
let pos_y = bg_position_y.to_used_value(own_position.height);
tile_image_axis(
bg_repeat.0,
&mut bounds.origin.x,
&mut bounds.size.width,
&mut tile_size.width,
&mut tile_spacing.width,
pos_x,
css_clip.origin.x,
css_clip.size.width,
);
tile_image_axis(
bg_repeat.1,
&mut bounds.origin.y,
&mut bounds.size.height,
&mut tile_size.height,
&mut tile_spacing.height,
pos_y,
css_clip.origin.y,
css_clip.size.height,
);
BackgroundPlacement {
bounds,
tile_size,
tile_spacing,
css_clip,
fixed,
}
}
fn tile_image_round(
position: &mut Au,
size: &mut Au,
@ -175,7 +301,7 @@ fn tile_image(position: &mut Au, size: &mut Au, absolute_anchor_origin: Au, imag
/// For either the x or the y axis ajust various values to account for tiling.
///
/// This is done separately for both axes because the repeat keywords may differ.
pub fn tile_image_axis(
fn tile_image_axis(
repeat: BackgroundRepeatKeyword,
position: &mut Au,
size: &mut Au,
@ -510,3 +636,151 @@ fn position_to_offset(position: LengthOrPercentage, total_length: Au) -> f32 {
},
}
}
fn scale_border_radii(radii: BorderRadius, factor: f32) -> BorderRadius {
BorderRadius {
top_left: radii.top_left * factor,
top_right: radii.top_right * factor,
bottom_left: radii.bottom_left * factor,
bottom_right: radii.bottom_right * factor,
}
}
fn handle_overlapping_radii(size: LayoutSize, radii: BorderRadius) -> BorderRadius {
// 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: f32, radius_b: f32, edge_length: f32) -> f32 {
let required = radius_a + radius_b;
if required <= edge_length {
1.0
} else {
edge_length / required
}
}
let top_factor = scale_factor(radii.top_left.width, radii.top_right.width, size.width);
let bottom_factor = scale_factor(
radii.bottom_left.width,
radii.bottom_right.width,
size.width,
);
let left_factor = scale_factor(radii.top_left.height, radii.bottom_left.height, size.height);
let right_factor = scale_factor(
radii.top_right.height,
radii.bottom_right.height,
size.height,
);
let min_factor = top_factor
.min(bottom_factor)
.min(left_factor)
.min(right_factor);
if min_factor < 1.0 {
scale_border_radii(radii, min_factor)
} else {
radii
}
}
pub fn build_border_radius(
abs_bounds: &Rect<Au>,
border_style: &style_structs::Border,
) -> BorderRadius {
// 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.to_layout(),
BorderRadius {
top_left: model::specified_border_radius(
border_style.border_top_left_radius,
abs_bounds.size,
).to_layout(),
top_right: model::specified_border_radius(
border_style.border_top_right_radius,
abs_bounds.size,
).to_layout(),
bottom_right: model::specified_border_radius(
border_style.border_bottom_right_radius,
abs_bounds.size,
).to_layout(),
bottom_left: model::specified_border_radius(
border_style.border_bottom_left_radius,
abs_bounds.size,
).to_layout(),
},
)
}
/// Creates a four-sided border with uniform color, width and corner radius.
pub fn simple_normal_border(color: ColorF, style: BorderStyle) -> NormalBorder {
let side = BorderSide { color, style };
NormalBorder {
left: side,
right: side,
top: side,
bottom: side,
radius: BorderRadius::zero(),
}
}
/// Calculates radii for the inner side.
///
/// Radii usually describe the outer side of a border but for the lines to look nice
/// the inner radii need to be smaller depending on the line width.
///
/// This is used to determine clipping areas.
pub fn calculate_inner_border_radii(
mut radii: BorderRadius,
offsets: SideOffsets2D<Au>,
) -> BorderRadius {
fn inner_length(x: f32, offset: Au) -> f32 {
0.0_f32.max(x - offset.to_f32_px())
}
radii.top_left.width = inner_length(radii.top_left.width, offsets.left);
radii.bottom_left.width = inner_length(radii.bottom_left.width, offsets.left);
radii.top_right.width = inner_length(radii.top_right.width, offsets.right);
radii.bottom_right.width = inner_length(radii.bottom_right.width, offsets.right);
radii.top_left.height = inner_length(radii.top_left.height, offsets.top);
radii.top_right.height = inner_length(radii.top_right.height, offsets.top);
radii.bottom_left.height = inner_length(radii.bottom_left.height, offsets.bottom);
radii.bottom_right.height = inner_length(radii.bottom_right.height, offsets.bottom);
radii
}
/// Given an image and a border style constructs a border image.
///
/// See: https://drafts.csswg.org/css-backgrounds-3/#border-images
pub fn build_image_border_details(
webrender_image: WebRenderImageInfo,
border_style_struct: &style_structs::Border,
) -> Option<BorderDetails> {
let corners = &border_style_struct.border_image_slice.offsets;
let border_image_repeat = &border_style_struct.border_image_repeat;
if let Some(image_key) = webrender_image.key {
Some(BorderDetails::Image(ImageBorder {
image_key: image_key,
patch: NinePatchDescriptor {
width: webrender_image.width,
height: webrender_image.height,
slice: SideOffsets2D::new(
corners.0.resolve(webrender_image.height),
corners.1.resolve(webrender_image.width),
corners.2.resolve(webrender_image.height),
corners.3.resolve(webrender_image.width),
),
},
fill: border_style_struct.border_image_slice.fill,
// TODO(gw): Support border-image-outset
outset: SideOffsets2D::zero(),
repeat_horizontal: border_image_repeat.0.to_layout(),
repeat_vertical: border_image_repeat.1.to_layout(),
}))
} else {
None
}
}