⎇ 82574827f92c71f4d371f8c4effcd4f5b839daab
src/tree/taffy_tree.rs
Ñawpa willay
Pi imata llamkarqan
ch'uya
Enable correct image measure functions (#661)
1//! Contains [TaffyTree](crate::tree::TaffyTree): the default implementation of [LayoutTree](crate::tree::LayoutTree), and the error type for Taffy.
2#[cfg(not(feature = "std"))]
3use slotmap::SecondaryMap;
4#[cfg(feature = "std")]
5use slotmap::SparseSecondaryMap as SecondaryMap;
6use slotmap::{DefaultKey, SlotMap};
7
8use crate::geometry::Size;
9use crate::style::{AvailableSpace, Display, Style};
10use crate::tree::{
11 Cache, Layout, LayoutInput, LayoutOutput, LayoutPartialTree, NodeId, PrintTree, RoundTree, RunMode,
12 TraversePartialTree, TraverseTree,
13};
14use crate::util::debug::{debug_log, debug_log_node};
15use crate::util::sys::{new_vec_with_capacity, ChildrenVec, Vec};
16
17#[cfg(feature = "block_layout")]
18use crate::compute::compute_block_layout;
19#[cfg(feature = "flexbox")]
20use crate::compute::compute_flexbox_layout;
21#[cfg(feature = "grid")]
22use crate::compute::compute_grid_layout;
23use crate::compute::{
24 compute_cached_layout, compute_hidden_layout, compute_leaf_layout, compute_root_layout, round_layout,
25};
26
27/// The error Taffy generates on invalid operations
28pub type TaffyResult<T> = Result<T, TaffyError>;
29
30/// An error that occurs while trying to access or modify a node's children by index.
31#[derive(Debug)]
32pub enum TaffyError {
33 /// The parent node does not have a child at `child_index`. It only has `child_count` children
34 ChildIndexOutOfBounds {
35 /// The parent node whose child was being looked up
36 parent: NodeId,
37 /// The index that was looked up
38 child_index: usize,
39 /// The total number of children the parent has
40 child_count: usize,
41 },
42 /// The parent node was not found in the [`TaffyTree`](crate::TaffyTree) instance.
43 InvalidParentNode(NodeId),
44 /// The child node was not found in the [`TaffyTree`](crate::TaffyTree) instance.
45 InvalidChildNode(NodeId),
46 /// The supplied node was not found in the [`TaffyTree`](crate::TaffyTree) instance.
47 InvalidInputNode(NodeId),
48}
49
50impl core::fmt::Display for TaffyError {
51 fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
52 match self {
53 TaffyError::ChildIndexOutOfBounds { parent, child_index, child_count } => {
54 write!(f, "Index (is {child_index}) should be < child_count ({child_count}) for parent node {parent:?}")
55 }
56 TaffyError::InvalidParentNode(parent) => {
57 write!(f, "Parent Node {parent:?} is not in the TaffyTree instance")
58 }
59 TaffyError::InvalidChildNode(child) => write!(f, "Child Node {child:?} is not in the TaffyTree instance"),
60 TaffyError::InvalidInputNode(node) => write!(f, "Supplied Node {node:?} is not in the TaffyTree instance"),
61 }
62 }
63}
64
65#[cfg(feature = "std")]
66impl std::error::Error for TaffyError {}
67
68/// Global configuration values for a TaffyTree instance
69pub(crate) struct TaffyConfig {
70 /// Whether to round layout values
71 pub(crate) use_rounding: bool,
72}
73
74impl Default for TaffyConfig {
75 fn default() -> Self {
76 Self { use_rounding: true }
77 }
78}
79
80/// Layout information for a given [`Node`](crate::node::Node)
81///
82/// Stored in a [`TaffyTree`].
83struct NodeData {
84 /// The layout strategy used by this node
85 pub(crate) style: Style,
86
87 /// The always unrounded results of the layout computation. We must store this separately from the rounded
88 /// layout to avoid errors from rounding already-rounded values. See <https://github.com/DioxusLabs/taffy/issues/501>.
89 pub(crate) unrounded_layout: Layout,
90
91 /// The final results of the layout computation.
92 /// These may be rounded or unrounded depending on what the `use_rounding` config setting is set to.
93 pub(crate) final_layout: Layout,
94
95 /// Whether the node has context data associated with it or not
96 pub(crate) has_context: bool,
97
98 /// The cached results of the layout computation
99 pub(crate) cache: Cache,
100}
101
102impl NodeData {
103 /// Create the data for a new node
104 #[must_use]
105 pub const fn new(style: Style) -> Self {
106 Self {
107 style,
108 cache: Cache::new(),
109 unrounded_layout: Layout::new(),
110 final_layout: Layout::new(),
111 has_context: false,
112 }
113 }
114
115 /// Marks a node and all of its parents (recursively) as dirty
116 ///
117 /// This clears any cached data and signals that the data must be recomputed.
118 #[inline]
119 pub fn mark_dirty(&mut self) {
120 self.cache.clear()
121 }
122}
123
124/// An entire tree of UI nodes. The entry point to Taffy's high-level API.
125///
126/// Allows you to build a tree of UI nodes, run Taffy's layout algorithms over that tree, and then access the resultant layout.
127pub struct TaffyTree<NodeContext = ()> {
128 /// The [`NodeData`] for each node stored in this tree
129 nodes: SlotMap<DefaultKey, NodeData>,
130
131 /// Functions/closures that compute the intrinsic size of leaf nodes
132 node_context_data: SecondaryMap<DefaultKey, NodeContext>,
133
134 /// The children of each node
135 ///
136 /// The indexes in the outer vector correspond to the position of the parent [`NodeData`]
137 children: SlotMap<DefaultKey, ChildrenVec<NodeId>>,
138
139 /// The parents of each node
140 ///
141 /// The indexes in the outer vector correspond to the position of the child [`NodeData`]
142 parents: SlotMap<DefaultKey, Option<NodeId>>,
143
144 /// Layout mode configuration
145 config: TaffyConfig,
146}
147
148impl Default for TaffyTree {
149 fn default() -> TaffyTree<()> {
150 TaffyTree::new()
151 }
152}
153
154/// Iterator that wraps a slice of nodes, lazily converting them to u64
155pub struct TaffyTreeChildIter<'a>(core::slice::Iter<'a, NodeId>);
156impl<'a> Iterator for TaffyTreeChildIter<'a> {
157 type Item = NodeId;
158
159 fn next(&mut self) -> Option<Self::Item> {
160 self.0.next().copied()
161 }
162}
163
164// TraversePartialTree impl for TaffyTree
165impl<NodeContext> TraversePartialTree for TaffyTree<NodeContext> {
166 type ChildIter<'a> = TaffyTreeChildIter<'a> where Self: 'a;
167
168 #[inline(always)]
169 fn child_ids(&self, parent_node_id: NodeId) -> Self::ChildIter<'_> {
170 TaffyTreeChildIter(self.children[parent_node_id.into()].iter())
171 }
172
173 #[inline(always)]
174 fn child_count(&self, parent_node_id: NodeId) -> usize {
175 self.children[parent_node_id.into()].len()
176 }
177
178 #[inline(always)]
179 fn get_child_id(&self, parent_node_id: NodeId, id: usize) -> NodeId {
180 self.children[parent_node_id.into()][id]
181 }
182}
183
184// TraverseTree impl for TaffyTree
185impl<NodeContext> TraverseTree for TaffyTree<NodeContext> {}
186
187// PrintTree impl for TaffyTree
188impl<NodeContext> PrintTree for TaffyTree<NodeContext> {
189 #[inline(always)]
190 fn get_debug_label(&self, node_id: NodeId) -> &'static str {
191 let node = &self.nodes[node_id.into()];
192 let display = node.style.display;
193 let num_children = self.child_count(node_id);
194
195 match (num_children, display) {
196 (_, Display::None) => "NONE",
197 (0, _) => "LEAF",
198 #[cfg(feature = "block_layout")]
199 (_, Display::Block) => "BLOCK",
200 #[cfg(feature = "flexbox")]
201 (_, Display::Flex) => {
202 use crate::FlexDirection;
203 match node.style.flex_direction {
204 FlexDirection::Row | FlexDirection::RowReverse => "FLEX ROW",
205 FlexDirection::Column | FlexDirection::ColumnReverse => "FLEX COL",
206 }
207 }
208 #[cfg(feature = "grid")]
209 (_, Display::Grid) => "GRID",
210 }
211 }
212
213 #[inline(always)]
214 fn get_final_layout(&self, node_id: NodeId) -> &Layout {
215 &self.nodes[node_id.into()].final_layout
216 }
217}
218
219/// View over the Taffy tree that holds the tree itself along with a reference to the context
220/// and implements LayoutTree. This allows the context to be stored outside of the TaffyTree struct
221/// which makes the lifetimes of the context much more flexible.
222pub(crate) struct TaffyView<'t, NodeContext, MeasureFunction>
223where
224 MeasureFunction:
225 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>,
226{
227 /// A reference to the TaffyTree
228 pub(crate) taffy: &'t mut TaffyTree<NodeContext>,
229 /// The context provided for passing to measure functions if layout is run over this struct
230 pub(crate) measure_function: MeasureFunction,
231}
232
233// TraversePartialTree impl for TaffyView
234impl<'t, NodeContext, MeasureFunction> TraversePartialTree for TaffyView<'t, NodeContext, MeasureFunction>
235where
236 MeasureFunction:
237 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>,
238{
239 type ChildIter<'a> = TaffyTreeChildIter<'a> where Self: 'a;
240
241 #[inline(always)]
242 fn child_ids(&self, parent_node_id: NodeId) -> Self::ChildIter<'_> {
243 self.taffy.child_ids(parent_node_id)
244 }
245
246 #[inline(always)]
247 fn child_count(&self, parent_node_id: NodeId) -> usize {
248 self.taffy.child_count(parent_node_id)
249 }
250
251 #[inline(always)]
252 fn get_child_id(&self, parent_node_id: NodeId, child_index: usize) -> NodeId {
253 self.taffy.get_child_id(parent_node_id, child_index)
254 }
255}
256
257// TraverseTree impl for TaffyView
258impl<'t, NodeContext, MeasureFunction> TraverseTree for TaffyView<'t, NodeContext, MeasureFunction> where
259 MeasureFunction:
260 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>
261{
262}
263
264// LayoutPartialTree impl for TaffyView
265impl<'t, NodeContext, MeasureFunction> LayoutPartialTree for TaffyView<'t, NodeContext, MeasureFunction>
266where
267 MeasureFunction:
268 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>,
269{
270 #[inline(always)]
271 fn get_style(&self, node: NodeId) -> &Style {
272 &self.taffy.nodes[node.into()].style
273 }
274
275 #[inline(always)]
276 fn get_cache_mut(&mut self, node: NodeId) -> &mut Cache {
277 &mut self.taffy.nodes[node.into()].cache
278 }
279
280 #[inline(always)]
281 fn set_unrounded_layout(&mut self, node_id: NodeId, layout: &Layout) {
282 self.taffy.nodes[node_id.into()].unrounded_layout = *layout;
283 }
284
285 #[inline(always)]
286 fn compute_child_layout(&mut self, node: NodeId, inputs: LayoutInput) -> LayoutOutput {
287 // If RunMode is PerformHiddenLayout then this indicates that an ancestor node is `Display::None`
288 // and thus that we should lay out this node using hidden layout regardless of it's own display style.
289 if inputs.run_mode == RunMode::PerformHiddenLayout {
290 debug_log!("HIDDEN");
291 return compute_hidden_layout(self, node);
292 }
293
294 // We run the following wrapped in "compute_cached_layout", which will check the cache for an entry matching the node and inputs and:
295 // - Return that entry if exists
296 // - Else call the passed closure (below) to compute the result
297 //
298 // If there was no cache match and a new result needs to be computed then that result will be added to the cache
299 compute_cached_layout(self, node, inputs, |tree, node, inputs| {
300 let display_mode = tree.get_style(node).display;
301 let has_children = tree.child_count(node) > 0;
302
303 debug_log!(display_mode);
304 debug_log_node!(
305 inputs.known_dimensions,
306 inputs.parent_size,
307 inputs.available_space,
308 inputs.run_mode,
309 inputs.sizing_mode
310 );
311
312 // Dispatch to a layout algorithm based on the node's display style and whether the node has children or not.
313 match (display_mode, has_children) {
314 (Display::None, _) => compute_hidden_layout(tree, node),
315 #[cfg(feature = "block_layout")]
316 (Display::Block, true) => compute_block_layout(tree, node, inputs),
317 #[cfg(feature = "flexbox")]
318 (Display::Flex, true) => compute_flexbox_layout(tree, node, inputs),
319 #[cfg(feature = "grid")]
320 (Display::Grid, true) => compute_grid_layout(tree, node, inputs),
321 (_, false) => {
322 let node_key = node.into();
323 let style = &tree.taffy.nodes[node_key].style;
324 let has_context = tree.taffy.nodes[node_key].has_context;
325 let node_context = has_context.then(|| tree.taffy.node_context_data.get_mut(node_key)).flatten();
326 let measure_function = |known_dimensions, available_space| {
327 (tree.measure_function)(known_dimensions, available_space, node, node_context, style)
328 };
329 compute_leaf_layout(inputs, style, measure_function)
330 }
331 }
332 })
333 }
334}
335
336// RoundTree impl for TaffyView
337impl<'t, NodeContext, MeasureFunction> RoundTree for TaffyView<'t, NodeContext, MeasureFunction>
338where
339 MeasureFunction:
340 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>,
341{
342 #[inline(always)]
343 fn get_unrounded_layout(&self, node: NodeId) -> &Layout {
344 &self.taffy.nodes[node.into()].unrounded_layout
345 }
346
347 #[inline(always)]
348 fn set_final_layout(&mut self, node_id: NodeId, layout: &Layout) {
349 self.taffy.nodes[node_id.into()].final_layout = *layout;
350 }
351}
352
353#[allow(clippy::iter_cloned_collect)] // due to no-std support, we need to use `iter_cloned` instead of `collect`
354impl<NodeContext> TaffyTree<NodeContext> {
355 /// Creates a new [`TaffyTree`]
356 ///
357 /// The default capacity of a [`TaffyTree`] is 16 nodes.
358 #[must_use]
359 pub fn new() -> Self {
360 Self::with_capacity(16)
361 }
362
363 /// Creates a new [`TaffyTree`] that can store `capacity` nodes before reallocation
364 #[must_use]
365 pub fn with_capacity(capacity: usize) -> Self {
366 TaffyTree {
367 // TODO: make this method const upstream,
368 // so constructors here can be const
369 nodes: SlotMap::with_capacity(capacity),
370 children: SlotMap::with_capacity(capacity),
371 parents: SlotMap::with_capacity(capacity),
372 node_context_data: SecondaryMap::with_capacity(capacity),
373 config: TaffyConfig::default(),
374 }
375 }
376
377 /// Enable rounding of layout values. Rounding is enabled by default.
378 pub fn enable_rounding(&mut self) {
379 self.config.use_rounding = true;
380 }
381
382 /// Disable rounding of layout values. Rounding is enabled by default.
383 pub fn disable_rounding(&mut self) {
384 self.config.use_rounding = false;
385 }
386
387 /// Creates and adds a new unattached leaf node to the tree, and returns the node of the new node
388 pub fn new_leaf(&mut self, layout: Style) -> TaffyResult<NodeId> {
389 let id = self.nodes.insert(NodeData::new(layout));
390 let _ = self.children.insert(new_vec_with_capacity(0));
391 let _ = self.parents.insert(None);
392
393 Ok(id.into())
394 }
395
396 /// Creates and adds a new unattached leaf node to the tree, and returns the [`NodeId`] of the new node
397 ///
398 /// Creates and adds a new leaf node with a supplied context
399 pub fn new_leaf_with_context(&mut self, layout: Style, context: NodeContext) -> TaffyResult<NodeId> {
400 let mut data = NodeData::new(layout);
401 data.has_context = true;
402
403 let id = self.nodes.insert(data);
404 self.node_context_data.insert(id, context);
405
406 let _ = self.children.insert(new_vec_with_capacity(0));
407 let _ = self.parents.insert(None);
408
409 Ok(id.into())
410 }
411
412 /// Creates and adds a new node, which may have any number of `children`
413 pub fn new_with_children(&mut self, layout: Style, children: &[NodeId]) -> TaffyResult<NodeId> {
414 let id = NodeId::from(self.nodes.insert(NodeData::new(layout)));
415
416 for child in children {
417 self.parents[(*child).into()] = Some(id);
418 }
419
420 let _ = self.children.insert(children.iter().copied().collect::<_>());
421 let _ = self.parents.insert(None);
422
423 Ok(id)
424 }
425
426 /// Drops all nodes in the tree
427 pub fn clear(&mut self) {
428 self.nodes.clear();
429 self.children.clear();
430 self.parents.clear();
431 }
432
433 /// Remove a specific node from the tree and drop it
434 ///
435 /// Returns the id of the node removed.
436 pub fn remove(&mut self, node: NodeId) -> TaffyResult<NodeId> {
437 let key = node.into();
438 if let Some(parent) = self.parents[key] {
439 if let Some(children) = self.children.get_mut(parent.into()) {
440 children.retain(|f| *f != node);
441 }
442 }
443
444 // Remove "parent" references to a node when removing that node
445 if let Some(children) = self.children.get(key) {
446 for child in children.iter().copied() {
447 self.parents[child.into()] = None;
448 }
449 }
450
451 let _ = self.children.remove(key);
452 let _ = self.parents.remove(key);
453 let _ = self.nodes.remove(key);
454
455 Ok(node)
456 }
457
458 /// Sets the context data associated with the node
459 pub fn set_node_context(&mut self, node: NodeId, measure: Option<NodeContext>) -> TaffyResult<()> {
460 let key = node.into();
461 if let Some(measure) = measure {
462 self.nodes[key].has_context = true;
463 self.node_context_data.insert(key, measure);
464 } else {
465 self.nodes[key].has_context = false;
466 self.node_context_data.remove(key);
467 }
468
469 self.mark_dirty(node)?;
470
471 Ok(())
472 }
473
474 /// Gets a reference to the the context data associated with the node
475 pub fn get_node_context(&self, node: NodeId) -> Option<&NodeContext> {
476 self.node_context_data.get(node.into())
477 }
478
479 /// Gets a mutable reference to the the context data associated with the node
480 pub fn get_node_context_mut(&mut self, node: NodeId) -> Option<&mut NodeContext> {
481 self.node_context_data.get_mut(node.into())
482 }
483
484 /// Gets mutable references to the the context data associated with the nodes. All keys must be valid and disjoint, otherwise None is returned.
485 pub fn get_disjoint_node_context_mut<const N: usize>(
486 &mut self,
487 keys: [NodeId; N],
488 ) -> Option<[&mut NodeContext; N]> {
489 self.node_context_data.get_disjoint_mut(keys.map(|k| k.into()))
490 }
491
492 /// Adds a `child` node under the supplied `parent`
493 pub fn add_child(&mut self, parent: NodeId, child: NodeId) -> TaffyResult<()> {
494 let parent_key = parent.into();
495 let child_key = child.into();
496 self.parents[child_key] = Some(parent);
497 self.children[parent_key].push(child);
498 self.mark_dirty(parent)?;
499
500 Ok(())
501 }
502
503 /// Inserts a `child` node at the given `child_index` under the supplied `parent`, shifting all children after it to the right.
504 pub fn insert_child_at_index(&mut self, parent: NodeId, child_index: usize, child: NodeId) -> TaffyResult<()> {
505 let parent_key = parent.into();
506
507 let child_count = self.children[parent_key].len();
508 if child_index > child_count {
509 return Err(TaffyError::ChildIndexOutOfBounds { parent, child_index, child_count });
510 }
511
512 self.parents[child.into()] = Some(parent);
513 self.children[parent_key].insert(child_index, child);
514 self.mark_dirty(parent)?;
515
516 Ok(())
517 }
518
519 /// Directly sets the `children` of the supplied `parent`
520 pub fn set_children(&mut self, parent: NodeId, children: &[NodeId]) -> TaffyResult<()> {
521 let parent_key = parent.into();
522
523 // Remove node as parent from all its current children.
524 for child in &self.children[parent_key] {
525 self.parents[(*child).into()] = None;
526 }
527
528 // Build up relation node <-> child
529 for child in children {
530 self.parents[(*child).into()] = Some(parent);
531 }
532
533 let parent_children = &mut self.children[parent_key];
534 parent_children.clear();
535 children.iter().for_each(|child| parent_children.push(*child));
536
537 self.mark_dirty(parent)?;
538
539 Ok(())
540 }
541
542 /// Removes the `child` of the parent `node`
543 ///
544 /// The child is not removed from the tree entirely, it is simply no longer attached to its previous parent.
545 pub fn remove_child(&mut self, parent: NodeId, child: NodeId) -> TaffyResult<NodeId> {
546 let index = self.children[parent.into()].iter().position(|n| *n == child).unwrap();
547 self.remove_child_at_index(parent, index)
548 }
549
550 /// Removes the child at the given `index` from the `parent`
551 ///
552 /// The child is not removed from the tree entirely, it is simply no longer attached to its previous parent.
553 pub fn remove_child_at_index(&mut self, parent: NodeId, child_index: usize) -> TaffyResult<NodeId> {
554 let parent_key = parent.into();
555 let child_count = self.children[parent_key].len();
556 if child_index >= child_count {
557 return Err(TaffyError::ChildIndexOutOfBounds { parent, child_index, child_count });
558 }
559
560 let child = self.children[parent_key].remove(child_index);
561 self.parents[child.into()] = None;
562
563 self.mark_dirty(parent)?;
564
565 Ok(child)
566 }
567
568 /// Replaces the child at the given `child_index` from the `parent` node with the new `child` node
569 ///
570 /// The child is not removed from the tree entirely, it is simply no longer attached to its previous parent.
571 pub fn replace_child_at_index(
572 &mut self,
573 parent: NodeId,
574 child_index: usize,
575 new_child: NodeId,
576 ) -> TaffyResult<NodeId> {
577 let parent_key = parent.into();
578
579 let child_count = self.children[parent_key].len();
580 if child_index >= child_count {
581 return Err(TaffyError::ChildIndexOutOfBounds { parent, child_index, child_count });
582 }
583
584 self.parents[new_child.into()] = Some(parent);
585 let old_child = core::mem::replace(&mut self.children[parent_key][child_index], new_child);
586 self.parents[old_child.into()] = None;
587
588 self.mark_dirty(parent)?;
589
590 Ok(old_child)
591 }
592
593 /// Returns the child node of the parent `node` at the provided `child_index`
594 pub fn child_at_index(&self, parent: NodeId, child_index: usize) -> TaffyResult<NodeId> {
595 let parent_key = parent.into();
596 let child_count = self.children[parent_key].len();
597 if child_index >= child_count {
598 return Err(TaffyError::ChildIndexOutOfBounds { parent, child_index, child_count });
599 }
600
601 Ok(self.children[parent_key][child_index])
602 }
603
604 /// Returns the total number of nodes in the tree
605 pub fn total_node_count(&self) -> usize {
606 self.nodes.len()
607 }
608
609 /// Returns the `NodeId` of the parent node of the specified node (if it exists)
610 ///
611 /// - Return None if the specified node has no parent
612 /// - Panics if the specified node does not exist
613 pub fn parent(&self, child_id: NodeId) -> Option<NodeId> {
614 self.parents[child_id.into()]
615 }
616
617 /// Returns a list of children that belong to the parent node
618 pub fn children(&self, parent: NodeId) -> TaffyResult<Vec<NodeId>> {
619 Ok(self.children[parent.into()].iter().copied().collect::<_>())
620 }
621
622 /// Sets the [`Style`] of the provided `node`
623 pub fn set_style(&mut self, node: NodeId, style: Style) -> TaffyResult<()> {
624 self.nodes[node.into()].style = style;
625 self.mark_dirty(node)?;
626 Ok(())
627 }
628
629 /// Gets the [`Style`] of the provided `node`
630 pub fn style(&self, node: NodeId) -> TaffyResult<&Style> {
631 Ok(&self.nodes[node.into()].style)
632 }
633
634 /// Return this node layout relative to its parent
635 pub fn layout(&self, node: NodeId) -> TaffyResult<&Layout> {
636 if self.config.use_rounding {
637 Ok(&self.nodes[node.into()].final_layout)
638 } else {
639 Ok(&self.nodes[node.into()].unrounded_layout)
640 }
641 }
642
643 /// Marks the layout computation of this node and its children as outdated
644 ///
645 /// Performs a recursive depth-first search up the tree until the root node is reached
646 ///
647 /// WARNING: this will stack-overflow if the tree contains a cycle
648 pub fn mark_dirty(&mut self, node: NodeId) -> TaffyResult<()> {
649 /// WARNING: this will stack-overflow if the tree contains a cycle
650 fn mark_dirty_recursive(
651 nodes: &mut SlotMap<DefaultKey, NodeData>,
652 parents: &SlotMap<DefaultKey, Option<NodeId>>,
653 node_key: DefaultKey,
654 ) {
655 nodes[node_key].mark_dirty();
656
657 if let Some(Some(node)) = parents.get(node_key) {
658 mark_dirty_recursive(nodes, parents, (*node).into());
659 }
660 }
661
662 mark_dirty_recursive(&mut self.nodes, &self.parents, node.into());
663
664 Ok(())
665 }
666
667 /// Indicates whether the layout of this node (and its children) need to be recomputed
668 pub fn dirty(&self, node: NodeId) -> TaffyResult<bool> {
669 Ok(self.nodes[node.into()].cache.is_empty())
670 }
671
672 /// Updates the stored layout of the provided `node` and its children
673 pub fn compute_layout_with_measure<MeasureFunction>(
674 &mut self,
675 node_id: NodeId,
676 available_space: Size<AvailableSpace>,
677 measure_function: MeasureFunction,
678 ) -> Result<(), TaffyError>
679 where
680 MeasureFunction:
681 FnMut(Size<Option<f32>>, Size<AvailableSpace>, NodeId, Option<&mut NodeContext>, &Style) -> Size<f32>,
682 {
683 let use_rounding = self.config.use_rounding;
684 let mut taffy_view = TaffyView { taffy: self, measure_function };
685 compute_root_layout(&mut taffy_view, node_id, available_space);
686 if use_rounding {
687 round_layout(&mut taffy_view, node_id);
688 }
689 Ok(())
690 }
691
692 /// Updates the stored layout of the provided `node` and its children
693 pub fn compute_layout(&mut self, node: NodeId, available_space: Size<AvailableSpace>) -> Result<(), TaffyError> {
694 self.compute_layout_with_measure(node, available_space, |_, _, _, _, _| Size::ZERO)
695 }
696
697 /// Prints a debug representation of the tree's layout
698 #[cfg(feature = "std")]
699 pub fn print_tree(&mut self, root: NodeId) {
700 crate::util::print_tree(self, root)
701 }
702
703 /// Returns an instance of LayoutTree representing the TaffyTree
704 #[cfg(test)]
705 pub(crate) fn as_layout_tree(&mut self) -> impl LayoutPartialTree + '_ {
706 TaffyView { taffy: self, measure_function: |_, _, _, _, _| Size::ZERO }
707 }
708}
709
710#[cfg(test)]
711mod tests {
712
713 use super::*;
714 use crate::style::{Dimension, Display, FlexDirection};
715 use crate::style_helpers::*;
716 use crate::util::sys;
717
718 fn size_measure_function(
719 known_dimensions: Size<Option<f32>>,
720 _available_space: Size<AvailableSpace>,
721 _node_id: NodeId,
722 node_context: Option<&mut Size<f32>>,
723 _style: &Style,
724 ) -> Size<f32> {
725 known_dimensions.unwrap_or(node_context.cloned().unwrap_or(Size::ZERO))
726 }
727
728 #[test]
729 fn new_should_allocate_default_capacity() {
730 const DEFAULT_CAPACITY: usize = 16; // This is the capacity defined in the `impl Default`
731 let taffy: TaffyTree<()> = TaffyTree::new();
732
733 assert!(taffy.children.capacity() >= DEFAULT_CAPACITY);
734 assert!(taffy.parents.capacity() >= DEFAULT_CAPACITY);
735 assert!(taffy.nodes.capacity() >= DEFAULT_CAPACITY);
736 }
737
738 #[test]
739 fn test_with_capacity() {
740 const CAPACITY: usize = 8;
741 let taffy: TaffyTree<()> = TaffyTree::with_capacity(CAPACITY);
742
743 assert!(taffy.children.capacity() >= CAPACITY);
744 assert!(taffy.parents.capacity() >= CAPACITY);
745 assert!(taffy.nodes.capacity() >= CAPACITY);
746 }
747
748 #[test]
749 fn test_new_leaf() {
750 let mut taffy: TaffyTree<()> = TaffyTree::new();
751
752 let res = taffy.new_leaf(Style::default());
753 assert!(res.is_ok());
754 let node = res.unwrap();
755
756 // node should be in the taffy tree and have no children
757 assert!(taffy.child_count(node) == 0);
758 }
759
760 #[test]
761 fn new_leaf_with_context() {
762 let mut taffy: TaffyTree<Size<f32>> = TaffyTree::new();
763
764 let res = taffy.new_leaf_with_context(Style::default(), Size::ZERO);
765 assert!(res.is_ok());
766 let node = res.unwrap();
767
768 // node should be in the taffy tree and have no children
769 assert!(taffy.child_count(node) == 0);
770 }
771
772 /// Test that new_with_children works as expected
773 #[test]
774 fn test_new_with_children() {
775 let mut taffy: TaffyTree<()> = TaffyTree::new();
776 let child0 = taffy.new_leaf(Style::default()).unwrap();
777 let child1 = taffy.new_leaf(Style::default()).unwrap();
778 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
779
780 // node should have two children
781 assert_eq!(taffy.child_count(node), 2);
782 assert_eq!(taffy.children(node).unwrap()[0], child0);
783 assert_eq!(taffy.children(node).unwrap()[1], child1);
784 }
785
786 #[test]
787 fn remove_node_should_remove() {
788 let mut taffy: TaffyTree<()> = TaffyTree::new();
789
790 let node = taffy.new_leaf(Style::default()).unwrap();
791
792 let _ = taffy.remove(node).unwrap();
793 }
794
795 #[test]
796 fn remove_node_should_detach_hierarchy() {
797 let mut taffy: TaffyTree<()> = TaffyTree::new();
798
799 // Build a linear tree layout: <0> <- <1> <- <2>
800 let node2 = taffy.new_leaf(Style::default()).unwrap();
801 let node1 = taffy.new_with_children(Style::default(), &[node2]).unwrap();
802 let node0 = taffy.new_with_children(Style::default(), &[node1]).unwrap();
803
804 // Both node0 and node1 should have 1 child nodes
805 assert_eq!(taffy.children(node0).unwrap().as_slice(), &[node1]);
806 assert_eq!(taffy.children(node1).unwrap().as_slice(), &[node2]);
807
808 // Disconnect the tree: <0> <2>
809 let _ = taffy.remove(node1).unwrap();
810
811 // Both remaining nodes should have no child nodes
812 assert!(taffy.children(node0).unwrap().is_empty());
813 assert!(taffy.children(node2).unwrap().is_empty());
814 }
815
816 #[test]
817 fn remove_last_node() {
818 let mut taffy: TaffyTree<()> = TaffyTree::new();
819
820 let parent = taffy.new_leaf(Style::default()).unwrap();
821 let child = taffy.new_leaf(Style::default()).unwrap();
822 taffy.add_child(parent, child).unwrap();
823
824 taffy.remove(child).unwrap();
825 taffy.remove(parent).unwrap();
826 }
827
828 #[test]
829 fn set_measure() {
830 let mut taffy: TaffyTree<Size<f32>> = TaffyTree::new();
831 let node = taffy.new_leaf_with_context(Style::default(), Size { width: 200.0, height: 200.0 }).unwrap();
832 taffy.compute_layout_with_measure(node, Size::MAX_CONTENT, size_measure_function).unwrap();
833 assert_eq!(taffy.layout(node).unwrap().size.width, 200.0);
834
835 taffy.set_node_context(node, Some(Size { width: 100.0, height: 100.0 })).unwrap();
836 taffy.compute_layout_with_measure(node, Size::MAX_CONTENT, size_measure_function).unwrap();
837 assert_eq!(taffy.layout(node).unwrap().size.width, 100.0);
838 }
839
840 #[test]
841 fn set_measure_of_previously_unmeasured_node() {
842 let mut taffy: TaffyTree<Size<f32>> = TaffyTree::new();
843 let node = taffy.new_leaf(Style::default()).unwrap();
844 taffy.compute_layout_with_measure(node, Size::MAX_CONTENT, size_measure_function).unwrap();
845 assert_eq!(taffy.layout(node).unwrap().size.width, 0.0);
846
847 taffy.set_node_context(node, Some(Size { width: 100.0, height: 100.0 })).unwrap();
848 taffy.compute_layout_with_measure(node, Size::MAX_CONTENT, size_measure_function).unwrap();
849 assert_eq!(taffy.layout(node).unwrap().size.width, 100.0);
850 }
851
852 /// Test that adding `add_child()` works
853 #[test]
854 fn add_child() {
855 let mut taffy: TaffyTree<()> = TaffyTree::new();
856 let node = taffy.new_leaf(Style::default()).unwrap();
857 assert_eq!(taffy.child_count(node), 0);
858
859 let child0 = taffy.new_leaf(Style::default()).unwrap();
860 taffy.add_child(node, child0).unwrap();
861 assert_eq!(taffy.child_count(node), 1);
862
863 let child1 = taffy.new_leaf(Style::default()).unwrap();
864 taffy.add_child(node, child1).unwrap();
865 assert_eq!(taffy.child_count(node), 2);
866 }
867
868 #[test]
869 fn insert_child_at_index() {
870 let mut taffy: TaffyTree<()> = TaffyTree::new();
871
872 let child0 = taffy.new_leaf(Style::default()).unwrap();
873 let child1 = taffy.new_leaf(Style::default()).unwrap();
874 let child2 = taffy.new_leaf(Style::default()).unwrap();
875
876 let node = taffy.new_leaf(Style::default()).unwrap();
877 assert_eq!(taffy.child_count(node), 0);
878
879 taffy.insert_child_at_index(node, 0, child0).unwrap();
880 assert_eq!(taffy.child_count(node), 1);
881 assert_eq!(taffy.children(node).unwrap()[0], child0);
882
883 taffy.insert_child_at_index(node, 0, child1).unwrap();
884 assert_eq!(taffy.child_count(node), 2);
885 assert_eq!(taffy.children(node).unwrap()[0], child1);
886 assert_eq!(taffy.children(node).unwrap()[1], child0);
887
888 taffy.insert_child_at_index(node, 1, child2).unwrap();
889 assert_eq!(taffy.child_count(node), 3);
890 assert_eq!(taffy.children(node).unwrap()[0], child1);
891 assert_eq!(taffy.children(node).unwrap()[1], child2);
892 assert_eq!(taffy.children(node).unwrap()[2], child0);
893 }
894
895 #[test]
896 fn set_children() {
897 let mut taffy: TaffyTree<()> = TaffyTree::new();
898
899 let child0 = taffy.new_leaf(Style::default()).unwrap();
900 let child1 = taffy.new_leaf(Style::default()).unwrap();
901 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
902
903 assert_eq!(taffy.child_count(node), 2);
904 assert_eq!(taffy.children(node).unwrap()[0], child0);
905 assert_eq!(taffy.children(node).unwrap()[1], child1);
906
907 let child2 = taffy.new_leaf(Style::default()).unwrap();
908 let child3 = taffy.new_leaf(Style::default()).unwrap();
909 taffy.set_children(node, &[child2, child3]).unwrap();
910
911 assert_eq!(taffy.child_count(node), 2);
912 assert_eq!(taffy.children(node).unwrap()[0], child2);
913 assert_eq!(taffy.children(node).unwrap()[1], child3);
914 }
915
916 /// Test that removing a child works
917 #[test]
918 fn remove_child() {
919 let mut taffy: TaffyTree<()> = TaffyTree::new();
920 let child0 = taffy.new_leaf(Style::default()).unwrap();
921 let child1 = taffy.new_leaf(Style::default()).unwrap();
922 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
923
924 assert_eq!(taffy.child_count(node), 2);
925
926 taffy.remove_child(node, child0).unwrap();
927 assert_eq!(taffy.child_count(node), 1);
928 assert_eq!(taffy.children(node).unwrap()[0], child1);
929
930 taffy.remove_child(node, child1).unwrap();
931 assert_eq!(taffy.child_count(node), 0);
932 }
933
934 #[test]
935 fn remove_child_at_index() {
936 let mut taffy: TaffyTree<()> = TaffyTree::new();
937 let child0 = taffy.new_leaf(Style::default()).unwrap();
938 let child1 = taffy.new_leaf(Style::default()).unwrap();
939 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
940
941 assert_eq!(taffy.child_count(node), 2);
942
943 taffy.remove_child_at_index(node, 0).unwrap();
944 assert_eq!(taffy.child_count(node), 1);
945 assert_eq!(taffy.children(node).unwrap()[0], child1);
946
947 taffy.remove_child_at_index(node, 0).unwrap();
948 assert_eq!(taffy.child_count(node), 0);
949 }
950
951 // Related to: https://github.com/DioxusLabs/taffy/issues/510
952 #[test]
953 fn remove_child_updates_parents() {
954 let mut taffy: TaffyTree<()> = TaffyTree::new();
955
956 let parent = taffy.new_leaf(Style::default()).unwrap();
957 let child = taffy.new_leaf(Style::default()).unwrap();
958
959 taffy.add_child(parent, child).unwrap();
960
961 taffy.remove(parent).unwrap();
962
963 // Once the parent is removed this shouldn't panic.
964 assert!(taffy.set_children(child, &[]).is_ok());
965 }
966
967 #[test]
968 fn replace_child_at_index() {
969 let mut taffy: TaffyTree<()> = TaffyTree::new();
970
971 let child0 = taffy.new_leaf(Style::default()).unwrap();
972 let child1 = taffy.new_leaf(Style::default()).unwrap();
973
974 let node = taffy.new_with_children(Style::default(), &[child0]).unwrap();
975 assert_eq!(taffy.child_count(node), 1);
976 assert_eq!(taffy.children(node).unwrap()[0], child0);
977
978 taffy.replace_child_at_index(node, 0, child1).unwrap();
979 assert_eq!(taffy.child_count(node), 1);
980 assert_eq!(taffy.children(node).unwrap()[0], child1);
981 }
982 #[test]
983 fn test_child_at_index() {
984 let mut taffy: TaffyTree<()> = TaffyTree::new();
985 let child0 = taffy.new_leaf(Style::default()).unwrap();
986 let child1 = taffy.new_leaf(Style::default()).unwrap();
987 let child2 = taffy.new_leaf(Style::default()).unwrap();
988 let node = taffy.new_with_children(Style::default(), &[child0, child1, child2]).unwrap();
989
990 assert!(if let Ok(result) = taffy.child_at_index(node, 0) { result == child0 } else { false });
991 assert!(if let Ok(result) = taffy.child_at_index(node, 1) { result == child1 } else { false });
992 assert!(if let Ok(result) = taffy.child_at_index(node, 2) { result == child2 } else { false });
993 }
994 #[test]
995 fn test_child_count() {
996 let mut taffy: TaffyTree<()> = TaffyTree::new();
997 let child0 = taffy.new_leaf(Style::default()).unwrap();
998 let child1 = taffy.new_leaf(Style::default()).unwrap();
999 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
1000
1001 assert!(taffy.child_count(node) == 2);
1002 assert!(taffy.child_count(child0) == 0);
1003 assert!(taffy.child_count(child1) == 0);
1004 }
1005
1006 #[allow(clippy::vec_init_then_push)]
1007 #[test]
1008 fn test_children() {
1009 let mut taffy: TaffyTree<()> = TaffyTree::new();
1010 let child0 = taffy.new_leaf(Style::default()).unwrap();
1011 let child1 = taffy.new_leaf(Style::default()).unwrap();
1012 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
1013
1014 let mut children = sys::Vec::new();
1015 children.push(child0);
1016 children.push(child1);
1017
1018 let children_result = taffy.children(node).unwrap();
1019 assert_eq!(children_result, children);
1020
1021 assert!(taffy.children(child0).unwrap().is_empty());
1022 }
1023 #[test]
1024 fn test_set_style() {
1025 let mut taffy: TaffyTree<()> = TaffyTree::new();
1026
1027 let node = taffy.new_leaf(Style::default()).unwrap();
1028 assert_eq!(taffy.style(node).unwrap().display, Display::Flex);
1029
1030 taffy.set_style(node, Style { display: Display::None, ..Style::default() }).unwrap();
1031 assert_eq!(taffy.style(node).unwrap().display, Display::None);
1032 }
1033 #[test]
1034 fn test_style() {
1035 let mut taffy: TaffyTree<()> = TaffyTree::new();
1036
1037 let style = Style { display: Display::None, flex_direction: FlexDirection::RowReverse, ..Default::default() };
1038
1039 let node = taffy.new_leaf(style.clone()).unwrap();
1040
1041 let res = taffy.style(node);
1042 assert!(res.is_ok());
1043 assert!(res.unwrap() == &style);
1044 }
1045 #[test]
1046 fn test_layout() {
1047 let mut taffy: TaffyTree<()> = TaffyTree::new();
1048 let node = taffy.new_leaf(Style::default()).unwrap();
1049
1050 // TODO: Improve this test?
1051 let res = taffy.layout(node);
1052 assert!(res.is_ok());
1053 }
1054
1055 #[test]
1056 fn test_mark_dirty() {
1057 let mut taffy: TaffyTree<()> = TaffyTree::new();
1058 let child0 = taffy.new_leaf(Style::default()).unwrap();
1059 let child1 = taffy.new_leaf(Style::default()).unwrap();
1060 let node = taffy.new_with_children(Style::default(), &[child0, child1]).unwrap();
1061
1062 taffy.compute_layout(node, Size::MAX_CONTENT).unwrap();
1063
1064 assert_eq!(taffy.dirty(child0).unwrap(), false);
1065 assert_eq!(taffy.dirty(child1).unwrap(), false);
1066 assert_eq!(taffy.dirty(node).unwrap(), false);
1067
1068 taffy.mark_dirty(node).unwrap();
1069 assert_eq!(taffy.dirty(child0).unwrap(), false);
1070 assert_eq!(taffy.dirty(child1).unwrap(), false);
1071 assert_eq!(taffy.dirty(node).unwrap(), true);
1072
1073 taffy.compute_layout(node, Size::MAX_CONTENT).unwrap();
1074 taffy.mark_dirty(child0).unwrap();
1075 assert_eq!(taffy.dirty(child0).unwrap(), true);
1076 assert_eq!(taffy.dirty(child1).unwrap(), false);
1077 assert_eq!(taffy.dirty(node).unwrap(), true);
1078 }
1079
1080 #[test]
1081 fn compute_layout_should_produce_valid_result() {
1082 let mut taffy: TaffyTree<()> = TaffyTree::new();
1083 let node_result = taffy.new_leaf(Style {
1084 size: Size { width: Dimension::Length(10f32), height: Dimension::Length(10f32) },
1085 ..Default::default()
1086 });
1087 assert!(node_result.is_ok());
1088 let node = node_result.unwrap();
1089 let layout_result = taffy.compute_layout(
1090 node,
1091 Size { width: AvailableSpace::Definite(100.), height: AvailableSpace::Definite(100.) },
1092 );
1093 assert!(layout_result.is_ok());
1094 }
1095
1096 #[test]
1097 fn make_sure_layout_location_is_top_left() {
1098 use crate::prelude::Rect;
1099
1100 let mut taffy: TaffyTree<()> = TaffyTree::new();
1101
1102 let node = taffy
1103 .new_leaf(Style {
1104 size: Size { width: Dimension::Percent(1f32), height: Dimension::Percent(1f32) },
1105 ..Default::default()
1106 })
1107 .unwrap();
1108
1109 let root = taffy
1110 .new_with_children(
1111 Style {
1112 size: Size { width: Dimension::Length(100f32), height: Dimension::Length(100f32) },
1113 padding: Rect {
1114 left: length(10f32),
1115 right: length(20f32),
1116 top: length(30f32),
1117 bottom: length(40f32),
1118 },
1119 ..Default::default()
1120 },
1121 &[node],
1122 )
1123 .unwrap();
1124
1125 taffy.compute_layout(root, Size::MAX_CONTENT).unwrap();
1126
1127 // If Layout::location represents top-left coord, 'node' location
1128 // must be (due applied 'root' padding): {x: 10, y: 30}.
1129 //
1130 // It's important, since result will be different for each other
1131 // coordinate space:
1132 // - bottom-left: {x: 10, y: 40}
1133 // - top-right: {x: 20, y: 30}
1134 // - bottom-right: {x: 20, y: 40}
1135 let layout = taffy.layout(node).unwrap();
1136 assert_eq!(layout.location.x, 10f32);
1137 assert_eq!(layout.location.y, 30f32);
1138 }
1139}