This PR makes a number of simplifications to the layout and constraint
features that were added after v0.25.0.
For users upgrading from v0.25.0, the net effect of this PR (along with
the other PRs) is the following:
- New `Flex` modes have been added.
- `Flex::Start` (new default)
- `Flex::Center`
- `Flex::End`
- `Flex::SpaceAround`
- `Flex::SpaceBetween`
- `Flex::Legacy` (old default)
- `Min(v)` grows to allocate excess space in all `Flex` modes instead of
shrinking (except in `Flex::Legacy` where it retains old behavior).
- `Fill(1)` grows to allocate excess space, growing equally with
`Min(v)`.
---
The following contains a summary of the changes in this PR and the
motivation behind them.
**`Flex`**
- Removes `Flex::Stretch`
- Renames `Flex::StretchLast` to `Flex::Legacy`
**`Constraint`**
- Removes `Fixed`
- Makes `Min(v)` grow as much as possible everywhere (except
`Flex::Legacy` where it retains the old behavior)
- Makes `Min(v)` grow equally as `Fill(1)` while respecting `Min` lower
bounds. When `Fill` and `Min` are used together, they both fill excess
space equally.
Allowing `Min(v)` to grow still allows users to build the same layouts
as before with `Flex::Start` with no breaking changes to the behavior.
This PR also removes the unstable feature `SegmentSize`.
This is a breaking change to the behavior of constraints. If users want
old behavior, they can use `Flex::Legacy`.
```rust
Layout::vertical([Length(25), Length(25)]).flex(Flex::Legacy)
```
Users that have constraint that exceed the available space will probably
not see any difference or see an improvement in their layouts. Any
layout with `Min` will be identical in `Flex::Start` and `Flex::Legacy`
so any layout with `Min` will not be breaking.
Previously, `Table` used `EvenDistribution` internally by default, but
with that gone the default is now `Flex::Start`. This changes the
behavior of `Table` (for the better in most cases). The only way for
users to get exactly the same as the old behavior is to change their
constraints. I imagine most users will be happier out of the box with
the new Table default.
Resolves https://github.com/ratatui-org/ratatui/issues/843
Thanks to @joshka for the direction
Follow up to https://github.com/ratatui-org/ratatui/pull/783
This PR introduces different priorities for each kind of constraint.
This PR also adds tests that specifies this behavior. This PR resolves a
number of broken tests.
Fixes https://github.com/ratatui-org/ratatui/issues/827
With this PR, the layout algorithm will do the following in order:
1. Ensure that all the segments are within the user provided area and
ensure that all segments and spacers are aligned next to each other
2. if a user provides a `layout.spacing`, it will enforce it.
3. ensure proportional elements are all proportional to each other
4. if a user provides a `Fixed(v)` constraint, it will enforce it.
5. `Min` / `Max` binding inequality constraints
6. `Length`
7. `Percentage`
8. `Ratio`
9. collapse `Min` or collapse `Max`
10. grow `Proportional` as much as possible
11. grow spacers as much as possible
This PR also returns the spacer areas as `Rects` to the user. Users can
then draw into the spacers as they see fit (thanks @joshka for the
idea). Here's a screenshot with the modified flex example:
<img width="569" alt="image"
src="https://github.com/ratatui-org/ratatui/assets/1813121/46c8901d-882c-43b0-ba87-b1d455099d8f">
This PR introduces a `strengths` module that has "default" weights that
give stable solutions as well as predictable behavior.
Added convenience functions left_aligned(), centered() and
right_aligned() plus unit tests. Updated example code.
Signed-off-by: Eelco Empting <me@eelco.de>
This commit adds `scroll` to the flex example. It also adds more examples to showcase how constraints interact. It improves the UI to make it easier to understand and short terminal friendly.
<img width="380" alt="image" src="https://github.com/ratatui-org/ratatui/assets/1813121/30541efc-ecbe-4e28-b4ef-4d5f1dc63fec"/>
---------
Co-authored-by: Dheepak Krishnamurthy <me@kdheepak.com>
This PR adds a new way to space elements in a `Layout`.
Loosely based on
[flexbox](https://css-tricks.com/snippets/css/a-guide-to-flexbox/), this
PR adds a `Flex` enum with the following variants:
- Start
- Center
- End
- SpaceAround
- SpaceBetween
<img width="380" alt="image" src="https://github.com/ratatui-org/ratatui/assets/1813121/b744518c-eae7-4e35-bbc4-fe3c95193cde">
It also adds two more variants, to make this backward compatible and to
make it replace `SegmentSize`:
- StretchLast (default in the `Flex` enum, also behavior matches old
default `SegmentSize::LastTakesRemainder`)
- Stretch (behavior matches `SegmentSize::EvenDistribution`)
The `Start` variant from above matches `SegmentSize::None`.
This allows `Flex` to be a complete replacement for `SegmentSize`, hence
this PR also deprecates the `segment_size` constructor on `Layout`.
`SegmentSize` is still used in `Table` but under the hood `segment_size`
maps to `Flex` with all tests passing unchanged.
I also put together a simple example for `Flex` layouts so that I could
test it visually, shared below:
https://github.com/ratatui-org/ratatui/assets/1813121/c8716c59-493f-4631-add5-feecf4bd4e06
