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