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authorLaurenz <laurmaedje@gmail.com>2022-11-03 11:44:53 +0100
committerLaurenz <laurmaedje@gmail.com>2022-11-03 13:35:39 +0100
commit37a7afddfaffd44cb9bc013c9506599267e08983 (patch)
tree20e7d62d3c5418baff01a21d0406b91bf3096214 /src/library/layout/flow.rs
parent56342bd972a13ffe21beaf2b87ab7eb1597704b4 (diff)
Split crates
Diffstat (limited to 'src/library/layout/flow.rs')
-rw-r--r--src/library/layout/flow.rs267
1 files changed, 0 insertions, 267 deletions
diff --git a/src/library/layout/flow.rs b/src/library/layout/flow.rs
deleted file mode 100644
index f4d18699..00000000
--- a/src/library/layout/flow.rs
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@@ -1,267 +0,0 @@
-use std::cmp::Ordering;
-
-use super::{AlignNode, PlaceNode, Spacing};
-use crate::library::prelude::*;
-use crate::library::text::ParNode;
-
-/// Arrange spacing, paragraphs and block-level nodes into a flow.
-///
-/// This node is reponsible for layouting both the top-level content flow and
-/// the contents of boxes.
-#[derive(Hash)]
-pub struct FlowNode(pub StyleVec<FlowChild>);
-
-/// A child of a flow node.
-#[derive(Hash, PartialEq)]
-pub enum FlowChild {
- /// Vertical spacing between other children.
- Spacing(Spacing),
- /// Arbitrary block-level content.
- Block(Content),
- /// A column / region break.
- Colbreak,
-}
-
-#[node(LayoutBlock)]
-impl FlowNode {}
-
-impl LayoutBlock for FlowNode {
- fn layout_block(
- &self,
- world: Tracked<dyn World>,
- regions: &Regions,
- styles: StyleChain,
- ) -> SourceResult<Vec<Frame>> {
- let mut layouter = FlowLayouter::new(regions);
-
- for (child, map) in self.0.iter() {
- let styles = map.chain(&styles);
- match child {
- FlowChild::Spacing(kind) => {
- layouter.layout_spacing(*kind, styles);
- }
- FlowChild::Block(block) => {
- layouter.layout_block(world, block, styles)?;
- }
- FlowChild::Colbreak => {
- layouter.finish_region();
- }
- }
- }
-
- Ok(layouter.finish())
- }
-}
-
-impl Debug for FlowNode {
- fn fmt(&self, f: &mut Formatter) -> fmt::Result {
- f.write_str("Flow ")?;
- self.0.fmt(f)
- }
-}
-
-impl Debug for FlowChild {
- fn fmt(&self, f: &mut Formatter) -> fmt::Result {
- match self {
- Self::Spacing(kind) => write!(f, "{:?}", kind),
- Self::Block(block) => block.fmt(f),
- Self::Colbreak => f.pad("Colbreak"),
- }
- }
-}
-
-impl PartialOrd for FlowChild {
- fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
- match (self, other) {
- (Self::Spacing(a), Self::Spacing(b)) => a.partial_cmp(b),
- _ => None,
- }
- }
-}
-
-/// Performs flow layout.
-pub struct FlowLayouter {
- /// The regions to layout children into.
- regions: Regions,
- /// Whether the flow should expand to fill the region.
- expand: Axes<bool>,
- /// The full size of `regions.size` that was available before we started
- /// subtracting.
- full: Size,
- /// The size used by the frames for the current region.
- used: Size,
- /// The sum of fractions in the current region.
- fr: Fr,
- /// Spacing and layouted blocks.
- items: Vec<FlowItem>,
- /// Finished frames for previous regions.
- finished: Vec<Frame>,
-}
-
-/// A prepared item in a flow layout.
-enum FlowItem {
- /// Absolute spacing between other items.
- Absolute(Abs),
- /// Fractional spacing between other items.
- Fractional(Fr),
- /// A frame for a layouted block and how to align it.
- Frame(Frame, Axes<Align>),
- /// An absolutely placed frame.
- Placed(Frame),
-}
-
-impl FlowLayouter {
- /// Create a new flow layouter.
- pub fn new(regions: &Regions) -> Self {
- let expand = regions.expand;
- let full = regions.first;
-
- // Disable vertical expansion for children.
- let mut regions = regions.clone();
- regions.expand.y = false;
-
- Self {
- regions,
- expand,
- full,
- used: Size::zero(),
- fr: Fr::zero(),
- items: vec![],
- finished: vec![],
- }
- }
-
- /// Layout spacing.
- pub fn layout_spacing(&mut self, spacing: Spacing, styles: StyleChain) {
- match spacing {
- Spacing::Relative(v) => {
- // Resolve the spacing and limit it to the remaining space.
- let resolved = v.resolve(styles).relative_to(self.full.y);
- let limited = resolved.min(self.regions.first.y);
- self.regions.first.y -= limited;
- self.used.y += limited;
- self.items.push(FlowItem::Absolute(resolved));
- }
- Spacing::Fractional(v) => {
- self.items.push(FlowItem::Fractional(v));
- self.fr += v;
- }
- }
- }
-
- /// Layout a block.
- pub fn layout_block(
- &mut self,
- world: Tracked<dyn World>,
- block: &Content,
- styles: StyleChain,
- ) -> SourceResult<()> {
- // Don't even try layouting into a full region.
- if self.regions.is_full() {
- self.finish_region();
- }
-
- // Placed nodes that are out of flow produce placed items which aren't
- // aligned later.
- if let Some(placed) = block.downcast::<PlaceNode>() {
- if placed.out_of_flow() {
- let frame = block.layout_block(world, &self.regions, styles)?.remove(0);
- self.items.push(FlowItem::Placed(frame));
- return Ok(());
- }
- }
-
- // How to align the block.
- let aligns = Axes::new(
- // For non-expanding paragraphs it is crucial that we align the
- // whole paragraph as it is itself aligned.
- styles.get(ParNode::ALIGN),
- // Vertical align node alignment is respected by the flow.
- block
- .downcast::<AlignNode>()
- .and_then(|aligned| aligned.aligns.y)
- .map(|align| align.resolve(styles))
- .unwrap_or(Align::Top),
- );
-
- let frames = block.layout_block(world, &self.regions, styles)?;
- let len = frames.len();
- for (i, mut frame) in frames.into_iter().enumerate() {
- // Set the generic block role.
- frame.apply_role(Role::GenericBlock);
-
- // Grow our size, shrink the region and save the frame for later.
- let size = frame.size();
- self.used.y += size.y;
- self.used.x.set_max(size.x);
- self.regions.first.y -= size.y;
- self.items.push(FlowItem::Frame(frame, aligns));
-
- if i + 1 < len {
- self.finish_region();
- }
- }
-
- Ok(())
- }
-
- /// Finish the frame for one region.
- pub fn finish_region(&mut self) {
- // Determine the size of the flow in this region dependening on whether
- // the region expands.
- let mut size = self.expand.select(self.full, self.used);
-
- // Account for fractional spacing in the size calculation.
- let remaining = self.full.y - self.used.y;
- if self.fr.get() > 0.0 && self.full.y.is_finite() {
- self.used.y = self.full.y;
- size.y = self.full.y;
- }
-
- let mut output = Frame::new(size);
- let mut offset = Abs::zero();
- let mut ruler = Align::Top;
-
- // Place all frames.
- for item in self.items.drain(..) {
- match item {
- FlowItem::Absolute(v) => {
- offset += v;
- }
- FlowItem::Fractional(v) => {
- offset += v.share(self.fr, remaining);
- }
- FlowItem::Frame(frame, aligns) => {
- ruler = ruler.max(aligns.y);
- let x = aligns.x.position(size.x - frame.width());
- let y = offset + ruler.position(size.y - self.used.y);
- let pos = Point::new(x, y);
- offset += frame.height();
- output.push_frame(pos, frame);
- }
- FlowItem::Placed(frame) => {
- output.push_frame(Point::zero(), frame);
- }
- }
- }
-
- // Advance to the next region.
- self.regions.next();
- self.full = self.regions.first;
- self.used = Size::zero();
- self.fr = Fr::zero();
- self.finished.push(output);
- }
-
- /// Finish layouting and return the resulting frames.
- pub fn finish(mut self) -> Vec<Frame> {
- if self.expand.y {
- while self.regions.backlog.len() > 0 {
- self.finish_region();
- }
- }
-
- self.finish_region();
- self.finished
- }
-}