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WIP: Better encapsulate LayoutContext #387

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88 changes: 14 additions & 74 deletions parley/src/builder.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ use super::style::{Brush, StyleProperty, TextStyle, WhiteSpaceCollapse};
use super::layout::Layout;

use alloc::string::String;
use alloc::vec::Vec;
use core::ops::RangeBounds;

use crate::inline_box::InlineBox;
Expand All @@ -28,7 +29,6 @@ impl<B: Brush> RangedBuilder<'_, B> {
pub fn push_default<'a>(&mut self, property: impl Into<StyleProperty<'a, B>>) {
let resolved = self
.lcx
.rcx
.resolve_property(self.fcx, &property.into(), self.scale);
self.lcx.ranged_style_builder.push_default(resolved);
}
Expand All @@ -40,7 +40,6 @@ impl<B: Brush> RangedBuilder<'_, B> {
) {
let resolved = self
.lcx
.rcx
.resolve_property(self.fcx, &property.into(), self.scale);
self.lcx.ranged_style_builder.push(resolved, range);
}
Expand All @@ -54,14 +53,8 @@ impl<B: Brush> RangedBuilder<'_, B> {
self.lcx.ranged_style_builder.finish(&mut self.lcx.styles);

// Call generic layout builder method
build_into_layout(
layout,
self.scale,
self.quantize,
text.as_ref(),
self.lcx,
self.fcx,
);
self.lcx
.build_into_layout(layout, self.scale, self.quantize, text.as_ref(), self.fcx);
}

pub fn build(self, text: impl AsRef<str>) -> Layout<B> {
Expand All @@ -84,7 +77,6 @@ impl<B: Brush> TreeBuilder<'_, B> {
pub fn push_style_span(&mut self, style: TextStyle<'_, B>) {
let resolved = self
.lcx
.rcx
.resolve_entire_style_set(self.fcx, &style, self.scale);
self.lcx.tree_style_builder.push_style_span(resolved);
}
Expand All @@ -96,11 +88,15 @@ impl<B: Brush> TreeBuilder<'_, B> {
's: 'iter,
B: 'iter,
{
self.lcx.tree_style_builder.push_style_modification_span(
properties
.into_iter()
.map(|p| self.lcx.rcx.resolve_property(self.fcx, p, self.scale)),
);
// FIXME: eliminate allocation if/when the "style builders" are extracted
// from the LayoutContext
let resolved_properties: Vec<_> = properties
.into_iter()
.map(|p| self.lcx.resolve_property(self.fcx, p, self.scale))
.collect();
self.lcx
.tree_style_builder
.push_style_modification_span(resolved_properties.into_iter());
}

pub fn pop_style_span(&mut self) {
Expand Down Expand Up @@ -134,7 +130,8 @@ impl<B: Brush> TreeBuilder<'_, B> {
let text = self.lcx.tree_style_builder.finish(&mut self.lcx.styles);

// Call generic layout builder method
build_into_layout(layout, self.scale, self.quantize, &text, self.lcx, self.fcx);
self.lcx
.build_into_layout(layout, self.scale, self.quantize, &text, self.fcx);

text
}
Expand All @@ -146,60 +143,3 @@ impl<B: Brush> TreeBuilder<'_, B> {
(layout, text)
}
}

fn build_into_layout<B: Brush>(
layout: &mut Layout<B>,
scale: f32,
quantize: bool,
text: &str,
lcx: &mut LayoutContext<B>,
fcx: &mut FontContext,
) {
lcx.analyze_text(text);

layout.data.clear();
layout.data.scale = scale;
layout.data.quantize = quantize;
layout.data.has_bidi = !lcx.bidi.levels().is_empty();
layout.data.base_level = lcx.bidi.base_level();
layout.data.text_len = text.len();

let mut char_index = 0;
for (i, style) in lcx.styles.iter().enumerate() {
for _ in text[style.range.clone()].chars() {
lcx.info[char_index].1 = i as u16;
char_index += 1;
}
}

// Copy the visual styles into the layout
layout
.data
.styles
.extend(lcx.styles.iter().map(|s| s.style.as_layout_style()));

// Sort the inline boxes as subsequent code assumes that they are in text index order.
// Note: It's important that this is a stable sort to allow users to control the order of contiguous inline boxes
lcx.inline_boxes.sort_by_key(|b| b.index);

{
let query = fcx.collection.query(&mut fcx.source_cache);
super::shape::shape_text(
&lcx.rcx,
query,
&lcx.styles,
&lcx.inline_boxes,
&lcx.info,
lcx.bidi.levels(),
&mut lcx.scx,
text,
layout,
);
}

// Move inline boxes into the layout
layout.data.inline_boxes.clear();
core::mem::swap(&mut layout.data.inline_boxes, &mut lcx.inline_boxes);

layout.data.finish();
}
94 changes: 90 additions & 4 deletions parley/src/context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,24 +16,28 @@ use super::style::{Brush, TextStyle};
use swash::shape::ShapeContext;
use swash::text::cluster::CharInfo;

use crate::Layout;
use crate::StyleProperty;
use crate::builder::TreeBuilder;
use crate::inline_box::InlineBox;
use crate::resolve::ResolvedProperty;

/// Shared scratch space used when constructing text layouts.
///
/// This type is designed to be a global resource with only one per-application (or per-thread).
pub struct LayoutContext<B: Brush = [u8; 4]> {
pub(crate) bidi: bidi::BidiResolver,
pub(crate) rcx: ResolveContext,
pub(crate) styles: Vec<RangedStyle<B>>,
pub(crate) inline_boxes: Vec<InlineBox>,

// Reusable style builders (to amortise allocations)
pub(crate) ranged_style_builder: RangedStyleBuilder<B>,
pub(crate) tree_style_builder: TreeStyleBuilder<B>,

pub(crate) info: Vec<(CharInfo, u16)>,
pub(crate) scx: ShapeContext,
// Internal contexts
bidi: bidi::BidiResolver,
rcx: ResolveContext,
scx: ShapeContext,
info: Vec<(CharInfo, u16)>,
}

impl<B: Brush> LayoutContext<B> {
Expand Down Expand Up @@ -179,6 +183,88 @@ impl<B: Brush> LayoutContext<B> {
}
}

pub(crate) fn resolve_property(
&mut self,
fcx: &mut FontContext,
property: &StyleProperty<'_, B>,
scale: f32,
) -> ResolvedProperty<B> {
self.rcx.resolve_property(fcx, property, scale)
}

pub(crate) fn resolve_entire_style_set(
&mut self,
fcx: &mut FontContext,
raw_style: &TextStyle<'_, B>,
scale: f32,
) -> ResolvedStyle<B> {
self.rcx.resolve_entire_style_set(fcx, raw_style, scale)
}

pub(crate) fn shape_into_layout(
&mut self,
fcx: &mut FontContext,
text: &str,
layout: &mut Layout<B>,
) {
let query = fcx.collection.query(&mut fcx.source_cache);
super::shape::shape_text(
&self.rcx,
query,
&self.styles,
&self.inline_boxes,
&self.info,
self.bidi.levels(),
&mut self.scx,
text,
layout,
);
}

pub(crate) fn build_into_layout(
&mut self,
layout: &mut Layout<B>,
scale: f32,
quantize: bool,
text: &str,
fcx: &mut FontContext,
) {
self.analyze_text(text);

layout.data.clear();
layout.data.scale = scale;
layout.data.quantize = quantize;
layout.data.has_bidi = !self.bidi.levels().is_empty();
layout.data.base_level = self.bidi.base_level();
layout.data.text_len = text.len();

let mut char_index = 0;
for (i, style) in self.styles.iter().enumerate() {
for _ in text[style.range.clone()].chars() {
self.info[char_index].1 = i as u16;
char_index += 1;
}
}

// Copy the visual styles into the layout
layout
.data
.styles
.extend(self.styles.iter().map(|s| s.style.as_layout_style()));

// Sort the inline boxes as subsequent code assumes that they are in text index order.
// Note: It's important that this is a stable sort to allow users to control the order of contiguous inline boxes
self.inline_boxes.sort_by_key(|b| b.index);

self.shape_into_layout(fcx, text, layout);

// Move inline boxes into the layout
layout.data.inline_boxes.clear();
core::mem::swap(&mut layout.data.inline_boxes, &mut self.inline_boxes);

layout.data.finish();
}

fn begin(&mut self) {
self.rcx.clear();
self.styles.clear();
Expand Down