1# Release Notes
2
3## Unreleased
4
5### Removed
6
7- `layout_flexbox()` has been removed from the prelude. Use `FlexboxAlgorithm::perform_layout()` instead.
8- The following methods have been removed from the `LayoutTree` trait: `parent`, `is_childless`, `layout`, `measure_node`, `needs_measure`, `cache_mut` and `mark_dirty`. These no longer need to be implemented in custom implementation of `LayoutTree`.
9
10### Changes
11
12- The Flexbox algorithm has now been moved behind the `flexbox` feature. The `flexbox` feature is enabled by default.
13- The `justify_self` property has been moved behind the `grid` feature.
14- `taffy::node::Node` has been replaced with `taffy::tree::NodeId`. This should make it much easier to implement the `LayoutTree` trait as the underlying type backing the node id now a `u64` rather than a `slotmap::DefaultKey`.
15
16## 0.3.11
17
18### Fixes
19
20- Fix exponential blowup when laying out trees containing nodes with min and max sizes.
21
22## 0.3.10
23
24### Fixes
25
26- Fix sizing of children when the available_space < min_size (#407)
27
28## 0.3.9
29
30### Fixes
31
32- Fix caching bug where a cached result would sometimes be incorrectly used when the amount of available space increased (bevyengine/bevy#8111) and (bevyengine/bevy#8124)
33
34## 0.3.8
35
36### Fixes
37
38- Fix incorrect min-content size for `flex-wrap: wrap` nodes (bevyengine/bevy#8082)
39
40## 0.3.7
41
42### Fixes
43
44- Fix: Make `padding` and `border` floor node sizes (#372)
45- Fix: Prevent percentages contributing to min-content sizes (#388) (also fixes bevyengine/bevy#8017)
46
47## 0.3.6
48
49### Fixes
50
51- Fix: Ignore `align_content` when `flex_wrap` is set to `nowrap` (#383)
52
53## 0.3.5
54
55### Fixes
56
57- Fix `display: none` when it is set on a flexbox child (#380)
58- Fix `display: none` when it is set on a grid child (#381)
59
60## 0.3.4
61
62### Fixes
63
64- Fix `display: none` when it is set for the only node in the hierarchy (#377)
65
66## 0.3.3
67
68### Added
69
70- Added `enable_rounding` and `disable_rounding` methods to the `Taffy` struct which enable consumers of Taffy to obtain unrounded `f32` values for the computed layouts if they want them. Rounding remains enabled by default.
71
72### Fixes
73
74- Fixed rounding algorithm such that it never leaves gaps between adjacent nodes (#369)
75- Fixed compiling with the `grid` feature disabled (#370)
76- Fixed compiling with the `std` feature disabled
77
78## 0.3.2
79
80### Fixes
81
82- Allow partial nested values to be deserialized into a `Style` using the `serde` feature.
83
84## 0.3.1
85
86### Fixes
87
88- The `serde` feature now works when the `grid` feature is enabled
89
90## 0.3.0
91
92### Highlights
93
94- [CSS Grid algorithm support](#new-feature-css-grid)
95- [Style helper functions](#new-feature-style-helpers)
96
97See below for details of breaking changes.
98
99### New Feature: CSS Grid
100
101We very excited to report that we now have support for CSS Grid layout. This is in addition to the existing Flexbox layout support, and the two modes interoperate. You can set a node to use Grid layout by setting the `display` property to `Display::Grid`.
102
103#### Learning Resources
104
105Taffy implements the CSS Grid specification faithfully, so documentation designed for the web should translate cleanly to Taffy's implementation. If you are interested in learning how to use CSS Grid, we would recommend the following resources:
106
107- [CSS Grid Garden](https://cssgridgarden.com/). This is an interactive tutorial/game that allows you to learn the essential parts of CSS Grid in a fun engaging way.
108- [A Complete Guide To CSS Grid](https://css-tricks.com/snippets/css/complete-guide-grid/) by CSS Tricks. This is detailed guide with illustrations and comphrehensive written explanation of the different Grid propertie and how they work.
109
110#### Supported Features & Properties
111
112In addition to the usual sizing/spacing proerties (size, min_size, padding, margin, etc), the following Grid style properties are supported on Grid Containers:
113
114| Property                  | Explanation                                                                                    |
115| ---                       | ---                                                                                            |
116| [`grid-template-columns`] | The track sizing functions of the grid's explicit columns                                      |
117| [`grid-template-rows`]    | The track sizing functions of the grid's explicit rows                                         |
118| [`grid-auto-rows`]        | Track sizing functions for the grid's implicitly generated rows                                |
119| [`grid-auto-columns`]     | Track sizing functions for the grid's implicitly generated columns                             |
120| [`grid-auto-flow`]        | Whether auto-placed items are placed row-wise or column-wise. And sparsely or densely.         |
121| [`gap`]                   | The size of the vertical and horizontal gaps between grid rows/columns                         |
122| [`align-content`]         | Align grid tracks within the container in the inline (horizontal) axis                         |
123| [`justify-content`]       | Align grid tracks within the container in the block (vertical) axis                            |
124| [`align-items`]           | Align the child items within their grid areas in the inline (horizontal) axis                  |
125| [`justify-items`]         | Align the child items within their grid areas in the block (vertical) axis                     |
126
127And the following Grid style properties are supported on Grid Items (children):
128
129| Property                  | Explanation                                                                                    |
130| ---                       | ---                                                                                            |
131| [`grid-row`]              | The (row) grid line the item starts at (or a span)                                             |
132| [`grid-column`]           | The (column) grid line the item end at (or a span)                                             |
133| [`align-self`]            | Align the item within it's grid area in the inline (horizontal) axis. Overrides `align-items`. |
134| [`justify-self`]          | Align the item within it's grid area in the block (vertical) axis. Overrides `justify-items`.  |
135
136[`grid-template-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-columns
137[`grid-template-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-rows
138[`grid-auto-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-rows
139[`grid-auto-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-columns
140[`grid-auto-flow`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-flow
141[`gap`]: https://developer.mozilla.org/en-US/docs/Web/CSS/gap
142[`align-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align_content
143[`justify-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify_content
144[`align-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-items
145[`justify-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-items
146[`grid-row`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-row
147[`grid-column`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-column
148[`align-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-self
149[`justify-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-self
150
151The following properties and features are not currently supported:
152
153- Subgrids
154- Masonry grid layout
155- Named grid lines
156- Named areas: `grid-template-areas` and `grid-area`
157- `grid-template` or `grid` shorthand
158
159#### Example
160
161See [examples/grid_holy_grail.rs](https://github.com/DioxusLabs/taffy/blob/main/examples/grid_holy_grail.rs) for an example using Taffy to implement the so-called [Holy Grail Layout](https://en.wikipedia.org/wiki/Holy_grail_(web_design)). If you want to run this example, the don't forget the enable the CSS Grid cargo feature:
162
163```bash
164cargo run --example grid_holy_grail --features grid
165```
166
167### New Feature: Style Helpers
168
169Ten new helper functions have added to the taffy prelude. These helper functions have short, intuitive names, and have generic return types which allow them to magically return the correct type depending on context. They make defining styles much easier, and means you won't typically need to use types like `Dimension` or `TrackSizingFunction` directly.
170
171For example, instead of:
172
173```rust
174let size : Size<Dimension> = Size { width: Dimension::Points(100.0), height: Dimension::Percent(50.0) };
175```
176
177you can now write
178
179```rust
180let size : Size<Dimension> = Size { width: points(100.0), height: percent(50.0) };
181```
182
183And that same helper function will work other types like `LengthPercentage` and `MinTrackSizingFunction` that also have a `Points` variant. There are also generic impl's for `Size<T>`, `Rect<T>` and `Line<T>` which means if your node is the same size in all dimensions you can even write
184
185```rust
186let size : Size<Dimension> = points(100.0);
187```
188
189Available style helpers:
190
191<table>
192  <thead><tr><th>Type(s)</th><th colspan="2">Helpers that work with that type</th></tr></thead>
193  <tbody>
194    <tr>
195      <td rowspan="3"><code>LengthPercentage</code></td>
196      <td><code>zero()</code></td>
197      <td>Generates a <code>Points</code> variant with the value <code>0.0</code></td>
198    </tr>
199    <tr>
200      <td><code>points(val:&nbsp;f32)</code></td>
201      <td>Generates a <code>Points</code> variant with the specified value</td>
202    </tr>
203    <tr>
204      <td><code>percent(val:&nbsp;f32)</code></td>
205      <td>Generates a <code>Percent</code> variant with the specified value.<br />Note that the scale of 0-1 not 0-100.</td>
206    </tr>
207    <tr>
208      <td rowspan="2"><code>LengthPercentageAuto</code><br /><code>Dimension</code></td>
209      <td colspan="2"><i>All helpers from <code>LengthPercentage</code> and...</i></td>
210    </tr>
211    <tr>
212      <td><code>auto()</code></td>
213      <td>Generates an <code>Auto</code> variant</td>
214    </tr>
215    <tr>
216      <td rowspan="3"><code>MinTrackSizingFunction</code></td>
217      <td colspan="2"><i>All helpers from <code>LengthPercentageAuto</code>/<code>Dimension</code> and...</i></td>
218    </tr>
219    <tr>
220      <td><code>min_content()</code></td>
221      <td>Generates an <code>MinContent</code> variant</td>
222    </tr>
223      <tr>
224      <td><code>max_content()</code></td>
225      <td>Generates an <code>MinContent</code> variant</td>
226    </tr>
227    <tr>
228      <td rowspan="3"><code>MaxTrackSizingFunction</code></td>
229      <td colspan="2"><i>All helpers from <code>MinTrackSizingFunction</code> and...</i></td>
230    </tr>
231    <tr>
232      <td><code>fit_content(limit:&nbsp;LengthPercentage)</code></td>
233      <td>Generates a <code>FitContent</code> variant with the specified limit.<br />Nest the <code>points</code> or <code>percent</code> helper inside this function to specified the limit.</td>
234    </tr>
235      <tr>
236      <td><code>fr(fraction:&nbsp;f32)</code></td>
237      <td>Generates a <code>Fraction</code> (<code>fr</code>) variant with the specified flex fraction </td>
238    </tr>
239    <tr>
240      <td rowspan="3"><code>NonRepeatingTrackSizingFunction</code></td>
241      <td colspan="2"><i>All helpers from <code>MaxTrackSizingFunction</code> and...</i></td>
242    </tr>
243    <tr>
244      <td><code>minmax(min: MinTrackSizingFunction, max: MaxTrackSizingFunction)</code></td>
245      <td>Equivalent to CSS <code>minmax()</code> function.</td>
246    </tr>
247    <tr>
248      <td><code>flex(fraction:&nbsp;f32)</code></td>
249      <td>Equivalent to CSS <code>minmax(0px, 1fr)</code>. This is likely what you want if you want evenly sized rows/columns.</td>
250    </tr>
251    <tr>
252      <td rowspan="2"><code>TrackSizingFunction</code></td>
253      <td colspan="2"><i>All helpers from <code>NonRepeatingTrackSizingFunction</code> and...</i></td>
254    </tr>
255    <tr>
256      <td><code>repeat(rep: GridTrackRepetition, tracks: Vec&lt;TrackSizingFunction&gt;)</code></td>
257      <td>Equivalent to css <code>repeat()</code> function.</td>
258    </tr>
259    <tr>
260      <td><code>Vec&lt;TrackSizingFunction&gt;</code></td>
261      <td><code>evenly_sized_tracks(count:&nbsp;u16)</code></td>
262      <td>Equivalent to CSS <code>repeat(count, minmax(0px, 1fr)</code></td>
263    </tr>
264    <tr>
265      <td rowspan="3"><code>AvailableSpace</code></td>
266      <td><code>auto()</code></td>
267      <td>Generates an <code>Auto</code> variant</td>
268    </tr>
269    <tr>
270      <td><code>min_content()</code></td>
271      <td>Generates an <code>MinContent</code> variant</td>
272    </tr>
273      <tr>
274      <td><code>max_content()</code></td>
275      <td>Generates an <code>MinContent</code> variant</td>
276    </tr>
277    <tr>
278      <td><code>Size&lt;T&gt;</code></td>
279      <td colspan="2">Any helper that works for <code>T</code> will also work for <code>Size&lt;T&gt;</code> and will set both <code>width</code> and <code>height</code> to that value</td>
280    </tr>
281    <tr>
282      <td><code>Rect&lt;T&gt;</code></td>
283      <td colspan="2">Any helper that works for <code>T</code> will also work for <code>Rect&lt;T&gt;</code> and will set <code>top</code>, <code>left</code>, <code>bottom</code>, and <code>right</code> to that value</td>
284    </tr>
285  </tbody>
286</table>
287
288### Breaking API changes
289
290#### Changes to alignment style types
291
292- `AlignContent` and `JustifyContent` has been merged.
293  - `JustifyContent` is now an alias of `AlignContent` and contains the `Stretch` variant.
294  - This variant will be *ignored* (falling back to `Start`) when applied Flexbox containers. It is valid value for Grid containers.
295- `AlignItems` and `AlignSelf` have been merged.
296  - The `Auto` variant of `AlignSelf` has been removed. You should now use `Option::None` if you wish to specify `AlignSelf::Auto`.
297  - `AlignSelf` is now an alias of `AlignItems`.
298  - `JustifyItems` and `JustifySelf` aliases have been added. These properties have no affect on Flexbox containers, but apply to Grid containers.
299- `Default` impls have been removed from all alignment types. This is because the correct default varies by property, and the types are now shared between multiple properties. The `Style` struct still has a default for each alignment property, so this is considered unlikely to affect you in practice.
300
301#### Strict style types
302
303- New types `LengthPercentage` and `LengthPercentageAuto` have been added.
304  - `LengthPercentage` is like `Dimension` but only contains the `Points` and `Percent` variants, which allows us to increase type safety for properties that don't support the `Auto` value.
305  - `LengthPercentageAuto` is currently identical to `Dimension` but will allow us to expand dimension in future to support values like `MinContent`, `MaxContent` and `FitContent`.
306- Some style properties have been updated to use either `LengthPercentage` or `LengthPercentageAuto` instead of `Dimension`. You will need to update your code, but it is recommended that you use the new style helpers (see above) rather than using the new types directly (although you certainly can use them directly if you want to).
307
308#### Position properties renamed
309
310- The `position` property is now renamed to `inset` and is now in line with [CSS inset specs](https://developer.mozilla.org/en-US/docs/Web/CSS/inset)
311- The `position_type` property is now renamed to `position` and is now in line with [CSS position specs](https://developer.mozilla.org/en-US/docs/Web/CSS/position). The `PositionType` enum has been similarly renamed to `Position`.
312
313#### Changes to `LayoutTree`
314
315- Added generic associated type to `LayoutTree` for a `ChildIter`, an iterator on the children of a given node.
316- Changed the `children` method of `LayoutTree` to return the `ChildIter` generic associated type to allow for custom tree storage implementations which do not store the children of a node contiguously.
317- Added `child_count`  method to `LayoutTree` for querying the number of children of a node. Required because the `children` method now returns an iterator instead of an array.
318- Added `is_childless` method to `LayoutTree` for querying whether a node has no children.
319
320#### `AvailableSpace` has been moved
321
322The `AvailableSpace` enum has been moved from the `layout` module to the `style` module. If you are importing it via the prelude then you will unaffected by the change.
323
324### Fixes
325
326- Flexbox nodes sized under a min-content constraint now size correctly (#291)
327- Aspect ratio is now applied correctly in many circumstances
328- Absolutely positioned items now apply margins correctly
329- Min/max size are now applied correctly
330- Inset applied incorrectly to relatively positioned flexbox children when both `top` and `bottom` or `left` and `right` were specified (#348)
331- Fix case where column-gap style could be used in place of row-gap style (when using a percentage gap with an indefinite container size)
332
333### Removed
334
335- Removed `top_from_points`, `bot_from_points`, `top_from_percent`, and `bot_from_percent` methods removed from `Rect<Dimension>`. These functions were incredibly specific for an unusual use case, so we would be surprised if anyone was using them. Please use the new style helpers instead.
336- Removed `min_main_size`, `max_main_size`, `min_cross_size`, `max_cross_size`, and `cross_size` methods from `Style`. Use the more general `cross` and `main` methods directly on the `size`, `min_size`, and `max_size` properties instead.
337- Removed `main_margin_start`, `main_margin_end`, `cross_margin_start`, `cross_margin_end` from `Style`. Use the more general `main_start`, `main_end`, `cross_start`, and `cross_end` on the `margin` property instead.
338
339## 0.2.2
340
341### Fixes
342
343- Border or padding on the horizontal axis could, in some cases, increase the height of nodes.
344
345## 0.2.1
346
347### Fixes
348
349- In case of conflicts, `min_size` now overrides `max_size` which overrides `size` (#261). This is the behaviour specified in the CSS specification, and was also the behaviour in Taffy `v0.1.0`, but a regression was introduced in Taffy `v0.2.0`.
350- `taffy::compute_layout` has been made public allowing Taffy to be used with custom storage (#263)
351
352## 0.2.0
353
354### New features
355
356#### Flexbox "gap" and `AlignContent::SpaceEvenly`
357
358The [gap](https://developer.mozilla.org/en-US/docs/Web/CSS/gap) property is now supported on flex containers. This can make it much easier to create even spacing or "gutters" between nodes.
359
360Additionally we have a `SpaceEvenly` variant to the `AlignContent` enum to support evenly spaced justification in the cross axis (equivalent to  `align-content: space-evenly` in CSS)
361
362#### Debug module and cargo feature
363
364Two debugging features have been added:
365
366- `taffy::debug::print_tree(&Taffy, root)` - This will print a debug representation of the computed layout of an entire node tree (starting at `root`), which can be useful for debugging layouts.
367- A cargo feature `debug`. This enabled debug logging of the layout computation process itself (this is probably mainly useful for those working taffy itself).
368
369### Performance improvements
370
371A number of performance improvements have landed since taffy 0.1:
372
373- Firstly, our custom `taffy::forest` storage implementation was ripped out and replaced with a much simpler implementation using the `slotmap` crate. This led to performance increases of up to 90%.
374- Secondly, the caching implementation was improved by upping the number of cache slots from 2 to 4 and tweaking how computed results are allocated to chache slots to better match the actual usage patterns of the flexbox layout algorithm. This had a particularly dramatic effect on deep hierachies (which often involve recomputing the same results repeatedly), fixing the exponential blowup that was previously exhibited on these trees and improving performance by over 1000x in some cases!
375
376#### Benchmarks vs. Taffy 0.1
377
378| Benchmark                                 | Taffy 0.1 | Taffy 0.2 | % change (0.1 -> 0.2) |
379| ---                                       | ---       | ---       | ---                   |
380| wide/1_000 nodes (2-level hierarchy)      | 699.18 µs | 445.01 µs | -36.279%              |
381| wide/10_000 nodes (2-level hierarchy)     | 8.8244 ms | 7.1313 ms | -16.352%              |
382| wide/100_000 nodes (2-level hierarchy)    | 204.48 ms | 242.93 ms | +18.803%              |
383| deep/4000 nodes (12-level hierarchy))     | 5.2320 s  | 2.7363 ms | -99.947%              |
384| deep/10_000 nodes (14-level hierarchy)    | 75.207 s  | 6.9415 ms | -99.991%              |
385| deep/100_000 nodes (17-level hierarchy)   | -         | 102.72 ms | -                     |
386| deep/1_000_000 nodes (20-level hierarchy) | -         | 799.35 ms | -                     |
387
388(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
389
390As you can see, we have actually regressed slightly in the "wide" benchmarks (where all nodes are siblings of a single parent node). Although it should be noted our results in these benchmarks are still very fast, especially on the 10,000 node benchmark which we consider to be the most realistic size where the result is measured in microseconds.
391
392However, in the "deep" benchmarks we see dramatic improvements. The previous version of Taffy suffered from exponential blowup in the case of deeply nested hierachies. This has resulted in somewhat silly improvements like the 10,000 node (14-level) hierachy where Taffy 0.2 is a full 1 million times faster than Taffy 0.1. We've also included results with larger numbers of nodes (although you're unlikely to need that many) to demonstrate that this scalability continues up to even deeper levels of nesting.
393
394#### Benchmarks vs. [Yoga](https://github.com/facebook/yoga)
395
396Yoga benchmarks run via it's node.js bindings (the `yoga-layout-prebuilt` npm package), they were run a few times manually and it was verified that variance in the numbers of each run was minimal. It should be noted that this is using an old version of Yoga.
397
398| Benchmark | Yoga | Taffy 0.2 |
399| --- | --- | --- |
400| yoga/10 nodes (1-level hierarchy) | 45.1670 µs | 33.297 ns |
401| yoga/100 nodes (2-level hierarchy) | 134.1250 µs | 336.53 ns |
402| yoga/1_000 nodes (3-level hierarchy) | 1.2221 ms | 3.8928 µs |
403| yoga/10_000 nodes (4-level hierarchy) | 13.8672 ms | 36.162 µs |
404| yoga/100_000 nodes (5-level hierarchy) | 141.5307 ms | 1.6404 ms |
405
406(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
407
408While we're trying not to get too excited (there could easily be an issue with our benchmarking methodology which make this an unfair comparison), we are pleased to see that we seem to be anywhere between 100x and 1000x times faster depending on the node count!
409
410### Breaking API changes
411
412#### Node creation changes
413
414- `taffy::Node` is now unique only to the Taffy instance from which it was created.
415- Renamed `Taffy.new_node(..)` -> `Taffy.new_with_children(..)`
416- Renamed `Taffy.new_leaf()` -> `Taffy.new_leaf_with_measure()`
417- Added `taffy::node::Taffy.new_leaf()` which allows the creation of new leaf-nodes without having to supply a measure function
418
419#### Error handling/representation improvements
420
421- Renamed `taffy::Error` -> `taffy::error::TaffyError`
422- Replaced `taffy::error::InvalidChild` with a new `InvalidChild` variant of `taffy::error::TaffyError`
423- Replaced `taffy::error::InvalidNode` with a new `InvalidNode` variant of `taffy::error::TaffyError`
424- The following method new return `Err(TaffyError::ChildIndexOutOfBounds)` instead of panicking:
425  - `taffy::Taffy::remove_child_at_index`
426  - `taffy::Taffy::replace_child_at_index`
427  - `taffy::Taffy::child_at_index`
428- `Taffy::remove` now returns a `Result<usize, Error>`, to indicate if the operation was sucessful (and if it was, which ID was invalidated).
429
430#### Some uses of `Option<f32>` replaced with a new `AvailableSpace` enum
431
432A new enum `Taffy::layout::AvailableSpace` has been added.
433
434The definition looks like this:
435
436```rust
437/// The amount of space available to a node in a given axis
438pub enum AvailableSpace {
439    /// The amount of space available is the specified number of pixels
440    Definite(f32),
441    /// The amount of space available is indefinite and the node should be laid out under a min-content constraint
442    MinContent,
443    /// The amount of space available is indefinite and the node should be laid out under a max-content constraint
444    MaxContent,
445}
446```
447
448This enum is now used instead of `Option<f32>` when calling `Taffy.compute_layout` (if you previously passing `Size::NONE` to `compute_layout`, then you will need to change this to `Size::MAX_CONTENT`).
449
450And a different instance of it is passed as a new second parameter to `MeasureFunc`. `MeasureFunc`s may choose to use this parameter in their computation or ignore it as they see fit. The canonical example of when it makes sense to use it is when laying out text. If `MinContent` has been passed in the axis in which the text is flowing (i.e. the horizontal axis for left-to-right text), then you should line-break at every possible opportunity (e.g. all word boundaries), whereas if `MaxContent` has been passed then you shouldn't line break at all..
451
452#### Builder methods are now `const` where possible
453
454- Several convenience constants have been defined: notably `Style::DEFAULT`
455- `Size<f32>.zero()` is now `Size::<f32>::ZERO`
456- `Point<f32>.zero()` is now  `Point::<f32>::ZERO`
457- `Size::undefined()` is now `Size::NONE`
458
459#### Removals
460
461- Removed `taffy::forest::Forest`. `taffy::node::Taffy` now handles it's own storage using a slotmap (which comes with a performance boost up to 90%).
462- Removed `taffy::number::Number`. Use `Option<f32>` is used instead
463  - the associated public `MinMax` and `OrElse` traits have also been removed; these should never have been public
464- Removed unused dependencies `hashbrown`, `hash32`, and `typenum`. `slotmap` is now the only required dependency (`num_traits` and `arrayvec` are also required if you wish to use taffy in a `no_std` environment).
465
466### Fixes
467
468- Miscellaneous correctness fixes which align our implementation with Chrome:
469
470  - Nodes can only ever have one parent
471  - Fixed rounding of fractional values to follow latest Chrome - values are now rounded the same regardless of their position
472  - Fixed computing free space when using both `flex-grow` and a minimum size
473  - Padding is now only subtracted when determining the available space if the node size is unspecified, following [section 9.2.2 of the flexbox spec](https://www.w3.org/TR/css-flexbox-1/#line-sizing)
474  - `MeasureFunc` (and hence `NodeData` and hence `Forest` and hence the public `Taffy` type) are now `Send` and `Sync`, enabling their use in async and parallel applications
475- Taffy can now be vendored using `cargo-vendor` (README.md is now included in package).
476
477## 0.1.0
478
479### 0.1.0 Changed
480
481- the `order` field of `Layout` is now public, and describes the relative z-ordering of nodes
482- renamed crate from `stretch2` to `taffy`
483- updated to the latest version of all dependencies to reduce upstream pain caused by duplicate dependencies
484- renamed `stretch::node::Strech` -> `taffy::node::Taffy`
485
486### 0.1.0 Fixed
487
488- fixed feature strategy for `alloc` and `std`: these can now be compiled together, with `std`'s types taking priority
489
490### 0.1.0 Removed
491
492- removed Javascript / Kotlin / Swift bindings
493  - the maintainer team lacks expertise to keep these working
494  - more serious refactors are planned, and this will be challenging to keep working through that process
495  - if you are interested in helping us maintain bindings to other languages, [get in touch](https://github.com/DioxusLabs/taffy/discussions)!
496- the `serde_camel_case` and `serde_kebab_case` features have been removed: they were poorly motivated and were not correctly additive (if both were enabled compilation would fail)
497- removed the `Direction` and `Overflow` structs, and the corresponding `direction` and `overflow` fields from `Style`
498  - these had no effect in the current code base and were actively misleading
499
500## stretch2 0.4.3
501
502This is the final release of `stretch`: migrate to the crate named `taffy` for future fixes and features!
503
504These notes describe the differences between this release and `stretch` 0.3.2, the abandoned crate from which this library was forked.
505
506### Changed
507
508- updated [assorted dependencies](https://github.com/vislyhq/stretch/commit/a6491117379cea52dedc9584d892594a143e8cb0)
509
510### Fixed
511
512- fixed an exponential performance blow-up with deep nesting
513- fixed percent height values, which were using parent width
514- recomputing layout no longer moves children of non-zero-positioned parent
515- fixed broken Swift bindings