Block stretch sizing fixes (#674)

* Block nodes should not stretch-fit themselves (stretch-fit sizing should
always be applied by the parent node)

* Stretch fit the root node if it is block display

src/compute/block.rs

@@ -58,12 +58,11 @@ struct BlockItem {
 
 /// Computes the layout of [`LayoutPartialTree`] according to the block layout algorithm
 pub fn compute_block_layout(tree: &mut impl LayoutPartialTree, node_id: NodeId, inputs: LayoutInput) -> LayoutOutput {
- let LayoutInput { known_dimensions, parent_size, available_space, run_mode, .. } = inputs;
+ let LayoutInput { known_dimensions, parent_size, run_mode, .. } = inputs;
  let style = tree.get_style(node_id);
 
  // Pull these out earlier to avoid borrowing issues
  let aspect_ratio = style.aspect_ratio;
- let margin = style.margin.resolve_or_zero(parent_size.width);
  let min_size = style.min_size.maybe_resolve(parent_size).maybe_apply_aspect_ratio(aspect_ratio);
  let max_size = style.max_size.maybe_resolve(parent_size).maybe_apply_aspect_ratio(aspect_ratio);
  let padding = style.padding.resolve_or_zero(parent_size.width);
@@ -81,15 +80,8 @@ pub fn compute_block_layout(tree: &mut impl LayoutPartialTree, node_id: NodeId,
  _ => None,
  });
 
- // Block nodes automatically stretch fit their width to fit available space if available space is definite
- let available_space_based_size =
- Size { width: available_space.width.into_option().maybe_sub(margin.horizontal_axis_sum()), height: None };
-
- let styled_based_known_dimensions = known_dimensions
- .or(min_max_definite_size)
- .or(clamped_style_size)
- .or(available_space_based_size)
- .maybe_max(padding_border_size);
+ let styled_based_known_dimensions =
+ known_dimensions.or(min_max_definite_size).or(clamped_style_size).maybe_max(padding_border_size);
 
  // Short-circuit layout if the container's size is fully determined by the container's size and the run mode
  // is ComputeSize (and thus the container's size is all that we're interested in)
@@ -362,6 +354,8 @@ fn perform_final_layout_on_in_flow_children(
  let known_dimensions = item
  .size
  .map_width(|width| {
+ // TODO: Allow stretch-sizing to be conditional, as there are exceptions.
+ // e.g. Table children of blocks do not stretch fit
  Some(
  width
  .unwrap_or(container_inner_width - item_non_auto_x_margin_sum)

src/compute/mod.rs

@@ -52,13 +52,58 @@ use crate::tree::{
 use crate::util::debug::{debug_log, debug_log_node, debug_pop_node, debug_push_node};
 use crate::util::sys::round;
 use crate::util::ResolveOrZero;
+use crate::{Display, MaybeMath, MaybeResolve};
 
 /// Compute layout for the root node in the tree
 pub fn compute_root_layout(tree: &mut impl LayoutPartialTree, root: NodeId, available_space: Size<AvailableSpace>) {
+ let mut known_dimensions = Size::NONE;
+
+ #[cfg(feature = "block_layout")]
+ {
+ let parent_size = available_space.into_options();
+ let style = tree.get_style(root);
+
+ if style.display == Display::Block {
+ // Pull these out earlier to avoid borrowing issues
+ let aspect_ratio = style.aspect_ratio;
+ let margin = style.margin.resolve_or_zero(parent_size.width);
+ let min_size = style.min_size.maybe_resolve(parent_size).maybe_apply_aspect_ratio(aspect_ratio);
+ let max_size = style.max_size.maybe_resolve(parent_size).maybe_apply_aspect_ratio(aspect_ratio);
+ let padding = style.padding.resolve_or_zero(parent_size.width);
+ let border = style.border.resolve_or_zero(parent_size.width);
+ let padding_border_size = (padding + border).sum_axes();
+ let clamped_style_size = style
+ .size
+ .maybe_resolve(parent_size)
+ .maybe_apply_aspect_ratio(aspect_ratio)
+ .maybe_clamp(min_size, max_size);
+
+ // If both min and max in a given axis are set and max <= min then this determines the size in that axis
+ let min_max_definite_size = min_size.zip_map(max_size, |min, max| match (min, max) {
+ (Some(min), Some(max)) if max <= min => Some(min),
+ _ => None,
+ });
+
+ // Block nodes automatically stretch fit their width to fit available space if available space is definite
+ let available_space_based_size = Size {
+ width: available_space.width.into_option().maybe_sub(margin.horizontal_axis_sum()),
+ height: None,
+ };
+
+ let styled_based_known_dimensions = known_dimensions
+ .or(min_max_definite_size)
+ .or(clamped_style_size)
+ .or(available_space_based_size)
+ .maybe_max(padding_border_size);
+
+ known_dimensions = styled_based_known_dimensions;
+ }
+ }
+
  // Recursively compute node layout
  let output = tree.perform_child_layout(
  root,
- Size::NONE,
+ known_dimensions,
  available_space.into_options(),
  available_space,
  SizingMode::InherentSize,