Density tracking issue: #18078
This PR refactors our spacing system to use a more flexible and
maintainable approach. We've replaced the static `Spacing` enum with a
dynamically generated `DynamicSpacing` enum using a proc macro.
Enum variants now use a `BaseXX` format, where XX = the pixel value @
default rem size and the default UI density.
For example:
`CustomSpacing::Base16` would return 16px at the default UI scale &
density.
I'd love to find another name other than `Base` that is clear (to avoid
base_10, etc confusion), let me know if you have any ideas!
Changes:
- Introduced a new `derive_dynamic_spacing` proc macro to generate the
`DynamicSpacing` enum
- Updated all usages of `Spacing` to use the new `DynamicSpacing`
- Removed the `custom_spacing` function, mapping previous usages to
appropriate `DynamicSpacing` variants
- Improved documentation and type safety for spacing values
New usage example:
```rust
.child(
div()
.flex()
.flex_none()
.m(DynamicSpacing::Base04.px(cx))
.size(DynamicSpacing::Base16.rems(cx))
.children(icon),
)
```
vs old usage example:
```
.child(
div()
.flex()
.flex_none()
.m(Spacing::Small.px(cx))
.size(custom_spacing(px(16.)))
.children(icon),
)
```
Release Notes:
- N/A
This PR adds the `ui_macros` crate to allow building supporting macros
for the `ui` crate.
Additionally, it implements the `DerivePathStr` derive macro and the
`path_str` attribute macro. These macros work together to generate a
`path` method for enum variants, which is useful for creating
standardized string representations of enum variants.
The `DerivePathStr` macro provides the following functionality:
- Generates a `path` method for each enum variant.
- Allows specifying a prefix (required) and suffix (optional) for all
paths.
- Supports `strum` attributes for case conversion (e.g., snake_case,
lowercase).
Usage example:
```rust
#[derive(DerivePathStr)]
#[path_str(prefix = "my_prefix", suffix = ".txt")]
#[strum(serialize_all = "snake_case")]
enum MyEnum {
VariantOne,
VariantTwo,
}
// Generated paths:
// MyEnum::VariantOne.path() -> "my_prefix/variant_one.txt"
// MyEnum::VariantTwo.path() -> "my_prefix/variant_two.txt"
```
In a later PR this will be used to automate the creation of icon & image
paths in the `ui` crate.
This gives the following benefits:
1. Ensures standard naming of assets as paths are not manually
specified.
2. Makes adding new enum variants less tedious and error-prone.
3. Quickly catches missing or incorrect paths during compilation.
3. Adds a building block towards being able to lint for unused assets in
the future.
Release Notes:
- N/A
