1# Release Notes
2
3## 0.3.0
4
5### Highlights
6
7- [CSS Grid algorithm support](#new-feature-css-grid)
8- [Style helper functions](#new-feature-style-helpers)
9
10See below for details of breaking changes.
11
12### New Feature: CSS Grid
13
14We 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`.
15
16#### Learning Resources
17
18Taffy 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:
19
20- [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.
21- [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.
22
23#### Supported Features & Properties
24
25In addition to the usual sizing/spacing proerties (size, min_size, padding, margin, etc), the following Grid style properties are supported on Grid Containers:
26
27| Property                  | Explanation                                                                                    |
28| ---                       | ---                                                                                            |
29| [`grid-template-columns`] | The track sizing functions of the grid's explicit columns                                      |
30| [`grid-template-rows`]    | The track sizing functions of the grid's explicit rows                                         |
31| [`grid-auto-rows`]        | Track sizing functions for the grid's implicitly generated rows                                |
32| [`grid-auto-columns`]     | Track sizing functions for the grid's implicitly generated columns                             |
33| [`grid-auto-flow`]        | Whether auto-placed items are placed row-wise or column-wise. And sparsely or densely.         |
34| [`gap`]                   | The size of the vertical and horizontal gaps between grid rows/columns                         |
35| [`align-content`]         | Align grid tracks within the container in the inline (horizontal) axis                         |
36| [`justify-content`]       | Align grid tracks within the container in the block (vertical) axis                            |
37| [`align-items`]           | Align the child items within their grid areas in the inline (horizontal) axis                  |
38| [`justify-items`]         | Align the child items within their grid areas in the block (vertical) axis                     |
39
40And the following Grid style properties are supported on Grid Items (children):
41
42| Property                  | Explanation                                                                                    |
43| ---                       | ---                                                                                            |
44| [`grid-row`]              | The (row) grid line the item starts at (or a span)                                             |
45| [`grid-column`]           | The (column) grid line the item end at (or a span)                                             |
46| [`align-self`]            | Align the item within it's grid area in the inline (horizontal) axis. Overrides `align-items`. |
47| [`justify-self`]          | Align the item within it's grid area in the block (vertical) axis. Overrides `justify-items`.  |
48
49[`grid-template-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-columns
50[`grid-template-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-rows
51[`grid-auto-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-rows
52[`grid-auto-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-columns
53[`grid-auto-flow`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-flow
54[`gap`]: https://developer.mozilla.org/en-US/docs/Web/CSS/gap
55[`align-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align_content
56[`justify-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify_content
57[`align-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-items
58[`justify-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-items
59[`grid-row`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-row
60[`grid-column`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-column
61[`align-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-self
62[`justify-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-self
63
64The following properties and features are not currently supported:
65
66- Subgrids
67- Masonry grid layout
68- Named grid lines
69- Named areas: `grid-template-areas` and `grid-area`
70- `grid-template` or `grid` shorthand
71
72#### Example
73
74See [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:
75
76```bash
77cargo run --example grid_holy_grail --features grid
78```
79
80### New Feature: Style Helpers
81
82Ten 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.
83
84For example, instead of:
85
86```rust
87let size : Size<Dimension> = Size { width: Dimension::Points(100.0), height: Dimension::Percent(50.0) };
88```
89
90you can now write
91
92```rust
93let size : Size<Dimension> = Size { width: points(100.0), height: percent(50.0) };
94```
95
96And 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
97
98```rust
99let size : Size<Dimension> = points(100.0);
100```
101
102Available style helpers:
103
104<table>
105  <thead><tr><th>Type(s)</th><th colspan="2">Helpers that work with that type</th></tr></thead>
106  <tbody>
107    <tr>
108      <td rowspan="3"><code>LengthPercentage</code></td>
109      <td><code>zero()</code></td>
110      <td>Generates a <code>Points</code> variant with the value <code>0.0</code></td>
111    </tr>
112    <tr>
113      <td><code>points(val:&nbsp;f32)</code></td>
114      <td>Generates a <code>Points</code> variant with the specified value</td>
115    </tr>
116    <tr>
117      <td><code>percent(val:&nbsp;f32)</code></td>
118      <td>Generates a <code>Percent</code> variant with the specified value.<br />Note that the scale of 0-1 not 0-100.</td>
119    </tr>
120    <tr>
121      <td rowspan="2"><code>LengthPercentageAuto</code><br /><code>Dimension</code></td>
122      <td colspan="2"><i>All helpers from <code>LengthPercentage</code> and...</i></td>
123    </tr>
124    <tr>
125      <td><code>auto()</code></td>
126      <td>Generates an <code>Auto</code> variant</td>
127    </tr>
128    <tr>
129      <td rowspan="3"><code>MinTrackSizingFunction</code></td>
130      <td colspan="2"><i>All helpers from <code>LengthPercentageAuto</code>/<code>Dimension</code> and...</i></td>
131    </tr>
132    <tr>
133      <td><code>min_content()</code></td>
134      <td>Generates an <code>MinContent</code> variant</td>
135    </tr>
136      <tr>
137      <td><code>max_content()</code></td>
138      <td>Generates an <code>MinContent</code> variant</td>
139    </tr>
140    <tr>
141      <td rowspan="3"><code>MaxTrackSizingFunction</code></td>
142      <td colspan="2"><i>All helpers from <code>MinTrackSizingFunction</code> and...</i></td>
143    </tr>
144    <tr>
145      <td><code>fit_content(limit:&nbsp;LengthPercentage)</code></td>
146      <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>
147    </tr>
148      <tr>
149      <td><code>fr(fraction:&nbsp;f32)</code></td>
150      <td>Generates a <code>Fraction</code> (<code>fr</code>) variant with the specified flex fraction </td>
151    </tr>
152    <tr>
153      <td rowspan="3"><code>NonRepeatingTrackSizingFunction</code></td>
154      <td colspan="2"><i>All helpers from <code>MaxTrackSizingFunction</code> and...</i></td>
155    </tr>
156    <tr>
157      <td><code>minmax(min: MinTrackSizingFunction, max: MaxTrackSizingFunction)</code></td>
158      <td>Equivalent to CSS <code>minmax()</code> function.</td>
159    </tr>
160    <tr>
161      <td><code>flex(fraction:&nbsp;f32)</code></td>
162      <td>Equivalent to CSS <code>minmax(0px, 1fr)</code>. This is likely what you want if you want evenly sized rows/columns.</td>
163    </tr>
164    <tr>
165      <td rowspan="2"><code>TrackSizingFunction</code></td>
166      <td colspan="2"><i>All helpers from <code>NonRepeatingTrackSizingFunction</code> and...</i></td>
167    </tr>
168    <tr>
169      <td><code>repeat(rep: GridTrackRepetition, tracks: Vec&lt;TrackSizingFunction&gt;)</code></td>
170      <td>Equivalent to css <code>repeat()</code> function.</td>
171    </tr>
172    <tr>
173      <td><code>Vec&lt;TrackSizingFunction&gt;</code></td>
174      <td><code>evenly_sized_tracks(count:&nbsp;u16)</code></td>
175      <td>Equivalent to CSS <code>repeat(count, minmax(0px, 1fr)</code></td>
176    </tr>
177    <tr>
178      <td rowspan="3"><code>AvailableSpace</code></td>
179      <td><code>auto()</code></td>
180      <td>Generates an <code>Auto</code> variant</td>
181    </tr>
182    <tr>
183      <td><code>min_content()</code></td>
184      <td>Generates an <code>MinContent</code> variant</td>
185    </tr>
186      <tr>
187      <td><code>max_content()</code></td>
188      <td>Generates an <code>MinContent</code> variant</td>
189    </tr>
190    <tr>
191      <td><code>Size&lt;T&gt;</code></td>
192      <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>
193    </tr>
194    <tr>
195      <td><code>Rect&lt;T&gt;</code></td>
196      <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>
197    </tr>
198  </tbody>
199</table>
200
201### Breaking API changes
202
203#### Changes to alignment style types
204
205- `AlignContent` and `JustifyContent` has been merged.
206  - `JustifyContent` is now an alias of `AlignContent` and contains the `Stretch` variant.
207  - This variant will be *ignored* (falling back to `Start`) when applied Flexbox containers. It is valid value for Grid containers.
208- `AlignItems` and `AlignSelf` have been merged.
209  - The `Auto` variant of `AlignSelf` has been removed. You should now use `Option::None` if you wish to specify `AlignSelf::Auto`.
210  - `AlignSelf` is now an alias of `AlignItems`.
211  - `JustifyItems` and `JustifySelf` aliases have been added. These properties have no affect on Flexbox containers, but apply to Grid containers.
212- `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.
213
214#### Strict style types
215
216- New types `LengthPercentage` and `LengthPercentageAuto` have been added.
217  - `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.
218  - `LengthPercentageAuto` is currently identical to `Dimension` but will allow us to expand dimension in future to support values like `MinContent`, `MaxContent` and `FitContent`.
219- 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).
220
221#### Position properties renamed
222
223- 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)
224- 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`.
225
226#### Changes to `LayoutTree`
227
228- Added generic associated type to `LayoutTree` for a `ChildIter`, an iterator on the children of a given node.
229- 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.
230- 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.
231- Added `is_childless` method to `LayoutTree` for querying whether a node has no children.
232
233#### `AvailableSpace` has been moved
234
235The `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.
236
237### Fixes
238
239- Flexbox nodes sized under a min-content constraint now size correctly (#291)
240- Aspect ratio is now applied correctly in many circumstances
241- Absolutely positioned items now apply margins correctly
242- Min/max size are now applied correctly
243- Inset applied incorrectly to relatively positioned flexbox children when both `top` and `bottom` or `left` and `right` were specified (#348)
244- 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)
245
246### Removed
247
248- 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.
249- 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.
250- 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.
251
252## 0.2.2
253
254### Fixes
255
256- Border or padding on the horizontal axis could, in some cases, increase the height of nodes.
257
258## 0.2.1
259
260### Fixes
261
262- 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`.
263- `taffy::compute_layout` has been made public allowing Taffy to be used with custom storage (#263)
264
265## 0.2.0
266
267### New features
268
269#### Flexbox "gap" and `AlignContent::SpaceEvenly`
270
271The [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.
272
273Additionally 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)
274
275#### Debug module and cargo feature
276
277Two debugging features have been added:
278
279- `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.
280- A cargo feature `debug`. This enabled debug logging of the layout computation process itself (this is probably mainly useful for those working taffy itself).
281
282### Performance improvements
283
284A number of performance improvements have landed since taffy 0.1:
285
286- 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%.
287- 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!
288
289#### Benchmarks vs. Taffy 0.1
290
291| Benchmark                                 | Taffy 0.1 | Taffy 0.2 | % change (0.1 -> 0.2) |
292| ---                                       | ---       | ---       | ---                   |
293| wide/1_000 nodes (2-level hierarchy)      | 699.18 µs | 445.01 µs | -36.279%              |
294| wide/10_000 nodes (2-level hierarchy)     | 8.8244 ms | 7.1313 ms | -16.352%              |
295| wide/100_000 nodes (2-level hierarchy)    | 204.48 ms | 242.93 ms | +18.803%              |
296| deep/4000 nodes (12-level hierarchy))     | 5.2320 s  | 2.7363 ms | -99.947%              |
297| deep/10_000 nodes (14-level hierarchy)    | 75.207 s  | 6.9415 ms | -99.991%              |
298| deep/100_000 nodes (17-level hierarchy)   | -         | 102.72 ms | -                     |
299| deep/1_000_000 nodes (20-level hierarchy) | -         | 799.35 ms | -                     |
300
301(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
302
303As 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.
304
305However, 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.
306
307#### Benchmarks vs. [Yoga](https://github.com/facebook/yoga)
308
309Yoga 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.
310
311| Benchmark | Yoga | Taffy 0.2 |
312| --- | --- | --- |
313| yoga/10 nodes (1-level hierarchy) | 45.1670 µs | 33.297 ns |
314| yoga/100 nodes (2-level hierarchy) | 134.1250 µs | 336.53 ns |
315| yoga/1_000 nodes (3-level hierarchy) | 1.2221 ms | 3.8928 µs |
316| yoga/10_000 nodes (4-level hierarchy) | 13.8672 ms | 36.162 µs |
317| yoga/100_000 nodes (5-level hierarchy) | 141.5307 ms | 1.6404 ms |
318
319(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
320
321While 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!
322
323### Breaking API changes
324
325#### Node creation changes
326
327- `taffy::Node` is now unique only to the Taffy instance from which it was created.
328- Renamed `Taffy.new_node(..)` -> `Taffy.new_with_children(..)`
329- Renamed `Taffy.new_leaf()` -> `Taffy.new_leaf_with_measure()`
330- Added `taffy::node::Taffy.new_leaf()` which allows the creation of new leaf-nodes without having to supply a measure function
331
332#### Error handling/representation improvements
333
334- Renamed `taffy::Error` -> `taffy::error::TaffyError`
335- Replaced `taffy::error::InvalidChild` with a new `InvalidChild` variant of `taffy::error::TaffyError`
336- Replaced `taffy::error::InvalidNode` with a new `InvalidNode` variant of `taffy::error::TaffyError`
337- The following method new return `Err(TaffyError::ChildIndexOutOfBounds)` instead of panicking:
338  - `taffy::Taffy::remove_child_at_index`
339  - `taffy::Taffy::replace_child_at_index`
340  - `taffy::Taffy::child_at_index`
341- `Taffy::remove` now returns a `Result<usize, Error>`, to indicate if the operation was sucessful (and if it was, which ID was invalidated).
342
343#### Some uses of `Option<f32>` replaced with a new `AvailableSpace` enum
344
345A new enum `Taffy::layout::AvailableSpace` has been added.
346
347The definition looks like this:
348
349```rust
350/// The amount of space available to a node in a given axis
351pub enum AvailableSpace {
352    /// The amount of space available is the specified number of pixels
353    Definite(f32),
354    /// The amount of space available is indefinite and the node should be laid out under a min-content constraint
355    MinContent,
356    /// The amount of space available is indefinite and the node should be laid out under a max-content constraint
357    MaxContent,
358}
359```
360
361This 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`).
362
363And 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..
364
365#### Builder methods are now `const` where possible
366
367- Several convenience constants have been defined: notably `Style::DEFAULT`
368- `Size<f32>.zero()` is now `Size::<f32>::ZERO`
369- `Point<f32>.zero()` is now  `Point::<f32>::ZERO`
370- `Size::undefined()` is now `Size::NONE`
371
372#### Removals
373
374- 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%).
375- Removed `taffy::number::Number`. Use `Option<f32>` is used instead
376  - the associated public `MinMax` and `OrElse` traits have also been removed; these should never have been public
377- 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).
378
379### Fixes
380
381- Miscellaneous correctness fixes which align our implementation with Chrome:
382
383  - Nodes can only ever have one parent
384  - Fixed rounding of fractional values to follow latest Chrome - values are now rounded the same regardless of their position
385  - Fixed computing free space when using both `flex-grow` and a minimum size
386  - 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)
387  - `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
388- Taffy can now be vendored using `cargo-vendor` (README.md is now included in package).
389
390## 0.1.0
391
392### 0.1.0 Changed
393
394- the `order` field of `Layout` is now public, and describes the relative z-ordering of nodes
395- renamed crate from `stretch2` to `taffy`
396- updated to the latest version of all dependencies to reduce upstream pain caused by duplicate dependencies
397- renamed `stretch::node::Strech` -> `taffy::node::Taffy`
398
399### 0.1.0 Fixed
400
401- fixed feature strategy for `alloc` and `std`: these can now be compiled together, with `std`'s types taking priority
402
403### 0.1.0 Removed
404
405- removed Javascript / Kotlin / Swift bindings
406  - the maintainer team lacks expertise to keep these working
407  - more serious refactors are planned, and this will be challenging to keep working through that process
408  - if you are interested in helping us maintain bindings to other languages, [get in touch](https://github.com/DioxusLabs/taffy/discussions)!
409- 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)
410- removed the `Direction` and `Overflow` structs, and the corresponding `direction` and `overflow` fields from `Style`
411  - these had no effect in the current code base and were actively misleading
412
413## stretch2 0.4.3
414
415This is the final release of `stretch`: migrate to the crate named `taffy` for future fixes and features!
416
417These notes describe the differences between this release and `stretch` 0.3.2, the abandoned crate from which this library was forked.
418
419### Changed
420
421- updated [assorted dependencies](https://github.com/vislyhq/stretch/commit/a6491117379cea52dedc9584d892594a143e8cb0)
422
423### Fixed
424
425- fixed an exponential performance blow-up with deep nesting
426- fixed percent height values, which were using parent width
427- recomputing layout no longer moves children of non-zero-positioned parent
428- fixed broken Swift bindings