1# Release Notes
2
3## Unreleased
4
5### Breaking
6
7Many APIs have been renamed to replace `points` or `Points` with `length` or `Length`.
8This new name better describes one-dimentional measure of space in some unspecified unit
9which is often unrelated to the PostScript point or the CSS `pt` unit.
10
11This also removes a misleading similarity with the 2D `Point`,
12whose components can have any unit and are not even necessarily absolute lengths.
13
14Example usage change:
15
16```diff
17 use taffy::prelude::*;
18
19 // …
20
21 let header_node = taffy
22     .new_leaf(
23         Style {
24-            size: Size { width: points(800.0), height: points(100.0) },
25+            size: Size { width: length(800.0), height: length(100.0) },
26             ..Default::default()
27         },
28     ).unwrap();
29```
30
31### Added
32
33- Support for [CSS Block layout](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flow_Layout/Block_and_Inline_Layout_in_Normal_Flow#elements_participating_in_a_block_formatting_context) has been added. This can be used via the new `Display::Block` variant of the `Display` enum. Note that inline, inline-block and float have *not* been implemented. The use case supported is block container nodes which contain block-level children.
34- Added `insert_child_at_index()` method to the `Taffy` tree. This can be used to insert a child node at any position instead of just the end.
35
36### Removed
37
38- `layout_flexbox()` has been removed from the prelude. Use `FlexboxAlgorithm::perform_layout()` instead.
39- 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 implementations of `LayoutTree`.
40
41### Changes
42
43- The Flexbox algorithm has now been moved behind the `flexbox` feature. The `flexbox` feature is enabled by default.
44- The `justify_self` property has been moved behind the `grid` feature.
45- `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`.
46- Module organisation changes:
47  - The `math` module has been made private
48  - The `axis` module has been merged into the `geometry` module
49  - The debug module is no longer public. The `print_tree` function is now accesible under `util`.
50  - All types from the `node`, `data`, `layout`, `error` and `cache` modules have been moved to the  the `tree` module.
51- Fixed misspelling: `RunMode::PeformLayout` renamed into `RunMode::PerformLayout` (added missing `r`).
52
53## 0.3.13
54
55### Fixes
56
57- Fix rounding accumulation bug (#521) (Fixes #501 and bevyengine/bevy#8911)
58- Flexbox: pass correct cross-axis available space when computing an item's intrinsic main size (#522)(Fixes bevyengine/bevy#9350)
59- Flexbox: Subtract child margin not parent margin when computing stretch-alignment known size
60- Grid: Make CSS Grid algorithm correctly apply max width/height and available space when it is the root node (#491)
61- Grid: Fix CSS Grid "auto track" / placement bugs #481
62  - Fix divide by zero when using grid_auto_rows/grid_auto_columns with zero negative implicit tracks
63  - Fix over counting of tracks (leading to incorrect container heights) when auto-placing in grids that contain negative implicit tracks.
64  - Fix axis conflation in auto-placement code when grid_auto_flow is column
65  - Fix assignment of auto track sizes when initializing negative implicit tracks
66- Leaf: Apply margins to leaf nodes when computing available space for measure functions
67- Leaf: Reserve space for padding/borders in nodes with measure functions (#497)
68  
69  **NOTE: This has the potential to break layouts relying on the old behaviour.** However, such layouts would be relying on a style having no effect, so it is judged that such layouts are unlikely to exist in the wild. If this turns out not to be true then this fix will be reverted on the 0.3.x branch.
70
71### Dependencies
72
73- Upgrade `grid` to `0.10`. This eliminates the transitive dependency on `no-std-compat`.
74
75## 0.3.12
76
77### Fixes
78
79- Fix caching issue when toggling `display:none` on and off
80
81## 0.3.11
82
83### Fixes
84
85- Fix exponential blowup when laying out trees containing nodes with min and max sizes.
86
87## 0.3.10
88
89### Fixes
90
91- Fix sizing of children when the available_space < min_size (#407)
92
93## 0.3.9
94
95### Fixes
96
97- 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)
98
99## 0.3.8
100
101### Fixes
102
103- Fix incorrect min-content size for `flex-wrap: wrap` nodes (bevyengine/bevy#8082)
104
105## 0.3.7
106
107### Fixes
108
109- Fix: Make `padding` and `border` floor node sizes (#372)
110- Fix: Prevent percentages contributing to min-content sizes (#388) (also fixes bevyengine/bevy#8017)
111
112## 0.3.6
113
114### Fixes
115
116- Fix: Ignore `align_content` when `flex_wrap` is set to `nowrap` (#383)
117
118## 0.3.5
119
120### Fixes
121
122- Fix `display: none` when it is set on a flexbox child (#380)
123- Fix `display: none` when it is set on a grid child (#381)
124
125## 0.3.4
126
127### Fixes
128
129- Fix `display: none` when it is set for the only node in the hierarchy (#377)
130
131## 0.3.3
132
133### Added
134
135- 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.
136
137### Fixes
138
139- Fixed rounding algorithm such that it never leaves gaps between adjacent nodes (#369)
140- Fixed compiling with the `grid` feature disabled (#370)
141- Fixed compiling with the `std` feature disabled
142
143## 0.3.2
144
145### Fixes
146
147- Allow partial nested values to be deserialized into a `Style` using the `serde` feature.
148
149## 0.3.1
150
151### Fixes
152
153- The `serde` feature now works when the `grid` feature is enabled
154
155## 0.3.0
156
157### Highlights
158
159- [CSS Grid algorithm support](#new-feature-css-grid)
160- [Style helper functions](#new-feature-style-helpers)
161
162See below for details of breaking changes.
163
164### New Feature: CSS Grid
165
166We 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`.
167
168#### Learning Resources
169
170Taffy 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:
171
172- [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.
173- [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.
174
175#### Supported Features & Properties
176
177In addition to the usual sizing/spacing proerties (size, min_size, padding, margin, etc), the following Grid style properties are supported on Grid Containers:
178
179| Property                  | Explanation                                                                                    |
180| ---                       | ---                                                                                            |
181| [`grid-template-columns`] | The track sizing functions of the grid's explicit columns                                      |
182| [`grid-template-rows`]    | The track sizing functions of the grid's explicit rows                                         |
183| [`grid-auto-rows`]        | Track sizing functions for the grid's implicitly generated rows                                |
184| [`grid-auto-columns`]     | Track sizing functions for the grid's implicitly generated columns                             |
185| [`grid-auto-flow`]        | Whether auto-placed items are placed row-wise or column-wise. And sparsely or densely.         |
186| [`gap`]                   | The size of the vertical and horizontal gaps between grid rows/columns                         |
187| [`align-content`]         | Align grid tracks within the container in the inline (horizontal) axis                         |
188| [`justify-content`]       | Align grid tracks within the container in the block (vertical) axis                            |
189| [`align-items`]           | Align the child items within their grid areas in the inline (horizontal) axis                  |
190| [`justify-items`]         | Align the child items within their grid areas in the block (vertical) axis                     |
191
192And the following Grid style properties are supported on Grid Items (children):
193
194| Property                  | Explanation                                                                                    |
195| ---                       | ---                                                                                            |
196| [`grid-row`]              | The (row) grid line the item starts at (or a span)                                             |
197| [`grid-column`]           | The (column) grid line the item end at (or a span)                                             |
198| [`align-self`]            | Align the item within it's grid area in the inline (horizontal) axis. Overrides `align-items`. |
199| [`justify-self`]          | Align the item within it's grid area in the block (vertical) axis. Overrides `justify-items`.  |
200
201[`grid-template-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-columns
202[`grid-template-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-template-rows
203[`grid-auto-rows`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-rows
204[`grid-auto-columns`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-columns
205[`grid-auto-flow`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-flow
206[`gap`]: https://developer.mozilla.org/en-US/docs/Web/CSS/gap
207[`align-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align_content
208[`justify-content`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify_content
209[`align-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-items
210[`justify-items`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-items
211[`grid-row`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-row
212[`grid-column`]: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-column
213[`align-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/align-self
214[`justify-self`]: https://developer.mozilla.org/en-US/docs/Web/CSS/justify-self
215
216The following properties and features are not currently supported:
217
218- Subgrids
219- Masonry grid layout
220- Named grid lines
221- Named areas: `grid-template-areas` and `grid-area`
222- `grid-template` or `grid` shorthand
223
224#### Example
225
226See [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:
227
228```bash
229cargo run --example grid_holy_grail --features grid
230```
231
232### New Feature: Style Helpers
233
234Ten 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.
235
236For example, instead of:
237
238```rust
239let size : Size<Dimension> = Size { width: Dimension::Points(100.0), height: Dimension::Percent(50.0) };
240```
241
242you can now write
243
244```rust
245let size : Size<Dimension> = Size { width: points(100.0), height: percent(50.0) };
246```
247
248And 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
249
250```rust
251let size : Size<Dimension> = points(100.0);
252```
253
254Available style helpers:
255
256<table>
257  <thead><tr><th>Type(s)</th><th colspan="2">Helpers that work with that type</th></tr></thead>
258  <tbody>
259    <tr>
260      <td rowspan="3"><code>LengthPercentage</code></td>
261      <td><code>zero()</code></td>
262      <td>Generates a <code>Points</code> variant with the value <code>0.0</code></td>
263    </tr>
264    <tr>
265      <td><code>points(val:&nbsp;f32)</code></td>
266      <td>Generates a <code>Points</code> variant with the specified value</td>
267    </tr>
268    <tr>
269      <td><code>percent(val:&nbsp;f32)</code></td>
270      <td>Generates a <code>Percent</code> variant with the specified value.<br />Note that the scale of 0-1 not 0-100.</td>
271    </tr>
272    <tr>
273      <td rowspan="2"><code>LengthPercentageAuto</code><br /><code>Dimension</code></td>
274      <td colspan="2"><i>All helpers from <code>LengthPercentage</code> and...</i></td>
275    </tr>
276    <tr>
277      <td><code>auto()</code></td>
278      <td>Generates an <code>Auto</code> variant</td>
279    </tr>
280    <tr>
281      <td rowspan="3"><code>MinTrackSizingFunction</code></td>
282      <td colspan="2"><i>All helpers from <code>LengthPercentageAuto</code>/<code>Dimension</code> and...</i></td>
283    </tr>
284    <tr>
285      <td><code>min_content()</code></td>
286      <td>Generates an <code>MinContent</code> variant</td>
287    </tr>
288      <tr>
289      <td><code>max_content()</code></td>
290      <td>Generates an <code>MinContent</code> variant</td>
291    </tr>
292    <tr>
293      <td rowspan="3"><code>MaxTrackSizingFunction</code></td>
294      <td colspan="2"><i>All helpers from <code>MinTrackSizingFunction</code> and...</i></td>
295    </tr>
296    <tr>
297      <td><code>fit_content(limit:&nbsp;LengthPercentage)</code></td>
298      <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>
299    </tr>
300      <tr>
301      <td><code>fr(fraction:&nbsp;f32)</code></td>
302      <td>Generates a <code>Fraction</code> (<code>fr</code>) variant with the specified flex fraction </td>
303    </tr>
304    <tr>
305      <td rowspan="3"><code>NonRepeatingTrackSizingFunction</code></td>
306      <td colspan="2"><i>All helpers from <code>MaxTrackSizingFunction</code> and...</i></td>
307    </tr>
308    <tr>
309      <td><code>minmax(min: MinTrackSizingFunction, max: MaxTrackSizingFunction)</code></td>
310      <td>Equivalent to CSS <code>minmax()</code> function.</td>
311    </tr>
312    <tr>
313      <td><code>flex(fraction:&nbsp;f32)</code></td>
314      <td>Equivalent to CSS <code>minmax(0px, 1fr)</code>. This is likely what you want if you want evenly sized rows/columns.</td>
315    </tr>
316    <tr>
317      <td rowspan="2"><code>TrackSizingFunction</code></td>
318      <td colspan="2"><i>All helpers from <code>NonRepeatingTrackSizingFunction</code> and...</i></td>
319    </tr>
320    <tr>
321      <td><code>repeat(rep: GridTrackRepetition, tracks: Vec&lt;TrackSizingFunction&gt;)</code></td>
322      <td>Equivalent to css <code>repeat()</code> function.</td>
323    </tr>
324    <tr>
325      <td><code>Vec&lt;TrackSizingFunction&gt;</code></td>
326      <td><code>evenly_sized_tracks(count:&nbsp;u16)</code></td>
327      <td>Equivalent to CSS <code>repeat(count, minmax(0px, 1fr)</code></td>
328    </tr>
329    <tr>
330      <td rowspan="3"><code>AvailableSpace</code></td>
331      <td><code>auto()</code></td>
332      <td>Generates an <code>Auto</code> variant</td>
333    </tr>
334    <tr>
335      <td><code>min_content()</code></td>
336      <td>Generates an <code>MinContent</code> variant</td>
337    </tr>
338      <tr>
339      <td><code>max_content()</code></td>
340      <td>Generates an <code>MinContent</code> variant</td>
341    </tr>
342    <tr>
343      <td><code>Size&lt;T&gt;</code></td>
344      <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>
345    </tr>
346    <tr>
347      <td><code>Rect&lt;T&gt;</code></td>
348      <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>
349    </tr>
350  </tbody>
351</table>
352
353### Breaking API changes
354
355#### Changes to alignment style types
356
357- `AlignContent` and `JustifyContent` has been merged.
358  - `JustifyContent` is now an alias of `AlignContent` and contains the `Stretch` variant.
359  - This variant will be *ignored* (falling back to `Start`) when applied Flexbox containers. It is valid value for Grid containers.
360- `AlignItems` and `AlignSelf` have been merged.
361  - The `Auto` variant of `AlignSelf` has been removed. You should now use `Option::None` if you wish to specify `AlignSelf::Auto`.
362  - `AlignSelf` is now an alias of `AlignItems`.
363  - `JustifyItems` and `JustifySelf` aliases have been added. These properties have no affect on Flexbox containers, but apply to Grid containers.
364- `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.
365
366#### Strict style types
367
368- New types `LengthPercentage` and `LengthPercentageAuto` have been added.
369  - `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.
370  - `LengthPercentageAuto` is currently identical to `Dimension` but will allow us to expand dimension in future to support values like `MinContent`, `MaxContent` and `FitContent`.
371- 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).
372
373#### Position properties renamed
374
375- 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)
376- 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`.
377
378#### Changes to `LayoutTree`
379
380- Added generic associated type to `LayoutTree` for a `ChildIter`, an iterator on the children of a given node.
381- 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.
382- 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.
383- Added `is_childless` method to `LayoutTree` for querying whether a node has no children.
384
385#### `AvailableSpace` has been moved
386
387The `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.
388
389### Fixes
390
391- Flexbox nodes sized under a min-content constraint now size correctly (#291)
392- Aspect ratio is now applied correctly in many circumstances
393- Absolutely positioned items now apply margins correctly
394- Min/max size are now applied correctly
395- Inset applied incorrectly to relatively positioned flexbox children when both `top` and `bottom` or `left` and `right` were specified (#348)
396- 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)
397
398### Removed
399
400- 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.
401- 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.
402- 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.
403
404## 0.2.2
405
406### Fixes
407
408- Border or padding on the horizontal axis could, in some cases, increase the height of nodes.
409
410## 0.2.1
411
412### Fixes
413
414- 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`.
415- `taffy::compute_layout` has been made public allowing Taffy to be used with custom storage (#263)
416
417## 0.2.0
418
419### New features
420
421#### Flexbox "gap" and `AlignContent::SpaceEvenly`
422
423The [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.
424
425Additionally 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)
426
427#### Debug module and cargo feature
428
429Two debugging features have been added:
430
431- `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.
432- A cargo feature `debug`. This enabled debug logging of the layout computation process itself (this is probably mainly useful for those working taffy itself).
433
434### Performance improvements
435
436A number of performance improvements have landed since taffy 0.1:
437
438- 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%.
439- 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!
440
441#### Benchmarks vs. Taffy 0.1
442
443| Benchmark                                 | Taffy 0.1 | Taffy 0.2 | % change (0.1 -> 0.2) |
444| ---                                       | ---       | ---       | ---                   |
445| wide/1_000 nodes (2-level hierarchy)      | 699.18 µs | 445.01 µs | -36.279%              |
446| wide/10_000 nodes (2-level hierarchy)     | 8.8244 ms | 7.1313 ms | -16.352%              |
447| wide/100_000 nodes (2-level hierarchy)    | 204.48 ms | 242.93 ms | +18.803%              |
448| deep/4000 nodes (12-level hierarchy))     | 5.2320 s  | 2.7363 ms | -99.947%              |
449| deep/10_000 nodes (14-level hierarchy)    | 75.207 s  | 6.9415 ms | -99.991%              |
450| deep/100_000 nodes (17-level hierarchy)   | -         | 102.72 ms | -                     |
451| deep/1_000_000 nodes (20-level hierarchy) | -         | 799.35 ms | -                     |
452
453(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
454
455As 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.
456
457However, 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.
458
459#### Benchmarks vs. [Yoga](https://github.com/facebook/yoga)
460
461Yoga 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.
462
463| Benchmark | Yoga | Taffy 0.2 |
464| --- | --- | --- |
465| yoga/10 nodes (1-level hierarchy) | 45.1670 µs | 33.297 ns |
466| yoga/100 nodes (2-level hierarchy) | 134.1250 µs | 336.53 ns |
467| yoga/1_000 nodes (3-level hierarchy) | 1.2221 ms | 3.8928 µs |
468| yoga/10_000 nodes (4-level hierarchy) | 13.8672 ms | 36.162 µs |
469| yoga/100_000 nodes (5-level hierarchy) | 141.5307 ms | 1.6404 ms |
470
471(note that the table above contains multiple different units (milliseconds vs. microseconds vs. nanoseconds))
472
473While 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!
474
475### Breaking API changes
476
477#### Node creation changes
478
479- `taffy::Node` is now unique only to the Taffy instance from which it was created.
480- Renamed `Taffy.new_node(..)` -> `Taffy.new_with_children(..)`
481- Renamed `Taffy.new_leaf()` -> `Taffy.new_leaf_with_measure()`
482- Added `taffy::node::Taffy.new_leaf()` which allows the creation of new leaf-nodes without having to supply a measure function
483
484#### Error handling/representation improvements
485
486- Renamed `taffy::Error` -> `taffy::error::TaffyError`
487- Replaced `taffy::error::InvalidChild` with a new `InvalidChild` variant of `taffy::error::TaffyError`
488- Replaced `taffy::error::InvalidNode` with a new `InvalidNode` variant of `taffy::error::TaffyError`
489- The following method new return `Err(TaffyError::ChildIndexOutOfBounds)` instead of panicking:
490  - `taffy::Taffy::remove_child_at_index`
491  - `taffy::Taffy::replace_child_at_index`
492  - `taffy::Taffy::child_at_index`
493- `Taffy::remove` now returns a `Result<usize, Error>`, to indicate if the operation was sucessful (and if it was, which ID was invalidated).
494
495#### Some uses of `Option<f32>` replaced with a new `AvailableSpace` enum
496
497A new enum `Taffy::layout::AvailableSpace` has been added.
498
499The definition looks like this:
500
501```rust
502/// The amount of space available to a node in a given axis
503pub enum AvailableSpace {
504    /// The amount of space available is the specified number of pixels
505    Definite(f32),
506    /// The amount of space available is indefinite and the node should be laid out under a min-content constraint
507    MinContent,
508    /// The amount of space available is indefinite and the node should be laid out under a max-content constraint
509    MaxContent,
510}
511```
512
513This 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`).
514
515And 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..
516
517#### Builder methods are now `const` where possible
518
519- Several convenience constants have been defined: notably `Style::DEFAULT`
520- `Size<f32>.zero()` is now `Size::<f32>::ZERO`
521- `Point<f32>.zero()` is now  `Point::<f32>::ZERO`
522- `Size::undefined()` is now `Size::NONE`
523
524#### Removals
525
526- 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%).
527- Removed `taffy::number::Number`. Use `Option<f32>` is used instead
528  - the associated public `MinMax` and `OrElse` traits have also been removed; these should never have been public
529- 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).
530
531### Fixes
532
533- Miscellaneous correctness fixes which align our implementation with Chrome:
534
535  - Nodes can only ever have one parent
536  - Fixed rounding of fractional values to follow latest Chrome - values are now rounded the same regardless of their position
537  - Fixed computing free space when using both `flex-grow` and a minimum size
538  - 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)
539  - `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
540- Taffy can now be vendored using `cargo-vendor` (README.md is now included in package).
541
542## 0.1.0
543
544### 0.1.0 Changed
545
546- the `order` field of `Layout` is now public, and describes the relative z-ordering of nodes
547- renamed crate from `stretch2` to `taffy`
548- updated to the latest version of all dependencies to reduce upstream pain caused by duplicate dependencies
549- renamed `stretch::node::Strech` -> `taffy::node::Taffy`
550
551### 0.1.0 Fixed
552
553- fixed feature strategy for `alloc` and `std`: these can now be compiled together, with `std`'s types taking priority
554
555### 0.1.0 Removed
556
557- removed Javascript / Kotlin / Swift bindings
558  - the maintainer team lacks expertise to keep these working
559  - more serious refactors are planned, and this will be challenging to keep working through that process
560  - if you are interested in helping us maintain bindings to other languages, [get in touch](https://github.com/DioxusLabs/taffy/discussions)!
561- 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)
562- removed the `Direction` and `Overflow` structs, and the corresponding `direction` and `overflow` fields from `Style`
563  - these had no effect in the current code base and were actively misleading
564
565## stretch2 0.4.3
566
567This is the final release of `stretch`: migrate to the crate named `taffy` for future fixes and features!
568
569These notes describe the differences between this release and `stretch` 0.3.2, the abandoned crate from which this library was forked.
570
571### Changed
572
573- updated [assorted dependencies](https://github.com/vislyhq/stretch/commit/a6491117379cea52dedc9584d892594a143e8cb0)
574
575### Fixed
576
577- fixed an exponential performance blow-up with deep nesting
578- fixed percent height values, which were using parent width
579- recomputing layout no longer moves children of non-zero-positioned parent
580- fixed broken Swift bindings