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Diffstat (limited to 'src/layout/stack.rs')
| -rw-r--r-- | src/layout/stack.rs | 226 |
1 files changed, 0 insertions, 226 deletions
diff --git a/src/layout/stack.rs b/src/layout/stack.rs deleted file mode 100644 index 0fb3e3eb..00000000 --- a/src/layout/stack.rs +++ /dev/null @@ -1,226 +0,0 @@ -use std::fmt::{self, Debug, Formatter}; - -use super::*; - -/// A node that stacks its children. -#[derive(Debug, Hash)] -pub struct StackNode { - /// The stacking direction. - pub dir: Dir, - /// The children to be stacked. - pub children: Vec<StackChild>, -} - -/// A child of a stack node. -#[derive(Hash)] -pub enum StackChild { - /// Spacing between other nodes. - Spacing(Spacing), - /// Any block node and how to align it in the stack. - Node(BlockNode, Align), -} - -impl BlockLevel for StackNode { - fn layout( - &self, - ctx: &mut LayoutContext, - regions: &Regions, - ) -> Vec<Constrained<Rc<Frame>>> { - StackLayouter::new(self, regions.clone()).layout(ctx) - } -} - -impl Debug for StackChild { - fn fmt(&self, f: &mut Formatter) -> fmt::Result { - match self { - Self::Spacing(v) => write!(f, "Spacing({:?})", v), - Self::Node(node, _) => node.fmt(f), - } - } -} - -/// Performs stack layout. -struct StackLayouter<'a> { - /// The stack node to layout. - stack: &'a StackNode, - /// The axis of the block direction. - axis: SpecAxis, - /// Whether the stack should expand to fill the region. - expand: Spec<bool>, - /// The region to layout into. - regions: Regions, - /// The full size of `regions.current` that was available before we started - /// subtracting. - full: Size, - /// The generic size used by the frames for the current region. - used: Gen<Length>, - /// The sum of fractional ratios in the current region. - fr: Fractional, - /// Spacing and layouted nodes. - items: Vec<StackItem>, - /// Finished frames for previous regions. - finished: Vec<Constrained<Rc<Frame>>>, -} - -/// A prepared item in a stack layout. -enum StackItem { - /// Absolute spacing between other items. - Absolute(Length), - /// Fractional spacing between other items. - Fractional(Fractional), - /// A layouted child node. - Frame(Rc<Frame>, Align), -} - -impl<'a> StackLayouter<'a> { - /// Create a new stack layouter. - fn new(stack: &'a StackNode, mut regions: Regions) -> Self { - // Disable expansion along the block axis for children. - let axis = stack.dir.axis(); - let expand = regions.expand; - regions.expand.set(axis, false); - - Self { - stack, - axis, - expand, - full: regions.current, - regions, - used: Gen::zero(), - fr: Fractional::zero(), - items: vec![], - finished: vec![], - } - } - - /// Layout all children. - fn layout(mut self, ctx: &mut LayoutContext) -> Vec<Constrained<Rc<Frame>>> { - for child in &self.stack.children { - match *child { - StackChild::Spacing(Spacing::Linear(v)) => { - self.layout_absolute(v); - } - StackChild::Spacing(Spacing::Fractional(v)) => { - self.items.push(StackItem::Fractional(v)); - self.fr += v; - } - StackChild::Node(ref node, align) => { - self.layout_node(ctx, node, align); - } - } - } - - self.finish_region(); - self.finished - } - - /// Layout absolute spacing. - fn layout_absolute(&mut self, amount: Linear) { - // Resolve the linear, limiting it to the remaining available space. - let remaining = self.regions.current.get_mut(self.axis); - let resolved = amount.resolve(self.full.get(self.axis)); - let limited = resolved.min(*remaining); - *remaining -= limited; - self.used.block += limited; - self.items.push(StackItem::Absolute(resolved)); - } - - /// Layout a block node. - fn layout_node(&mut self, ctx: &mut LayoutContext, node: &BlockNode, align: Align) { - let frames = node.layout(ctx, &self.regions); - let len = frames.len(); - for (i, frame) in frames.into_iter().enumerate() { - // Grow our size. - let size = frame.item.size.to_gen(self.axis); - self.used.block += size.block; - self.used.inline.set_max(size.inline); - - // Remember the frame and shrink available space in the region for the - // following children. - self.items.push(StackItem::Frame(frame.item, align)); - *self.regions.current.get_mut(self.axis) -= size.block; - - if i + 1 < len { - self.finish_region(); - } - } - } - - /// Finish the frame for one region. - fn finish_region(&mut self) { - // Determine the size that remains for fractional spacing. - let remaining = self.full.get(self.axis) - self.used.block; - - // Determine the size of the stack in this region dependening on whether - // the region expands. - let used = self.used.to_size(self.axis); - let mut size = Size::new( - if self.expand.x { self.full.w } else { used.w }, - if self.expand.y { self.full.h } else { used.h }, - ); - - // Expand fully if there are fr spacings. - let full = self.full.get(self.axis); - if !self.fr.is_zero() && full.is_finite() { - size.set(self.axis, full); - } - - let mut output = Frame::new(size, size.h); - let mut before = Length::zero(); - let mut ruler = Align::Start; - let mut first = true; - - // Place all frames. - for item in self.items.drain(..) { - match item { - StackItem::Absolute(v) => before += v, - StackItem::Fractional(v) => { - let ratio = v / self.fr; - if remaining.is_finite() && ratio.is_finite() { - before += ratio * remaining; - } - } - StackItem::Frame(frame, align) => { - ruler = ruler.max(align); - - let parent = size.to_gen(self.axis); - let child = frame.size.to_gen(self.axis); - - // Align along the block axis. - let block = ruler.resolve( - self.stack.dir, - if self.stack.dir.is_positive() { - let after = self.used.block - before; - before .. parent.block - after - } else { - let before_with_self = before + child.block; - let after = self.used.block - before_with_self; - after .. parent.block - before_with_self - }, - ); - - let pos = Gen::new(Length::zero(), block).to_point(self.axis); - if first { - // The baseline of the stack is that of the first frame. - output.baseline = pos.y + frame.baseline; - first = false; - } - - output.push_frame(pos, frame); - before += child.block; - } - } - } - - // Generate tight constraints for now. - let mut cts = Constraints::new(self.expand); - cts.exact = self.full.to_spec().map(Some); - cts.base = self.regions.base.to_spec().map(Some); - - self.regions.next(); - self.full = self.regions.current; - self.used = Gen::zero(); - self.fr = Fractional::zero(); - self.finished.push(output.constrain(cts)); - } -} |