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# LevelingOptions
Options for a leveling run. Pass them to [`Project::level`](), or set them as `level` in [`EvaluateOptions`]() and [`SuggestOptions`]() to score candidates at the leveled stage. `LevelingOptions::default()` levels the whole project with the standard order. Override single fields with struct update syntax.
## Declaration
```rust
#[derive(Clone, Debug)]
pub struct LevelingOptions {
pub scope: Option,
pub basis: Option,
pub order: LevelingOrder,
pub within_slack_only: bool,
pub clear_first: bool,
pub allow_splits: bool,
pub step: LevelingStep,
}
impl Default for LevelingOptions
```
## Fields
### scope
```rust
pub scope: Option
```
Resources whose contention is resolved, tasks that may move, and the date range that triggers leveling. `None` covers the whole project.
Default: `None`.
### basis
```rust
pub basis: Option
```
Bucket size for detecting overallocation. `None` derives it from [`SchedulingConfig::duration_unit`](): `Day` for a `day` unit, `Hour` for `hour` and `minute`.
Default: `None`.
### order
```rust
pub order: LevelingOrder
```
Order in which contenders are picked to move.
Default: `LevelingOrder::Standard`.
### within_slack_only
```rust
pub within_slack_only: bool
```
`true` never moves a task past its total slack, so the project end of the base plan doesn't move. A window that can't be cleared this way stays with reason `slack-exhausted`.
Default: `false`.
### clear_first
```rust
pub clear_first: bool
```
`true` resets `leveling_delay` and `pauses` on in-scope tasks before leveling. `false` keeps them, and leveling adds to them.
Default: `true`.
### allow_splits
```rust
pub allow_splits: bool
```
`true` lets leveling split a task by adding or extending [`pauses`](). `false` makes every correction a whole-task `leveling_delay`; existing pauses are kept unless `clear_first` clears them.
Default: `true`.
### step
```rust
pub step: LevelingStep
```
How far one correction moves a task.
Default: `LevelingStep::Minimal`.
See [`Project::level`]() for the errors.
## Example
```rust
use plen_core::{
AssignmentData, DateTime, LevelingOptions, LevelingOrder, LevelingScope, Project,
ProjectData, ResourceData, SolveOptions, TaskData,
};
fn main() -> Result<(), Box> {
let start = DateTime::from_ymd_hm(2026, 1, 5, 0, 0).ok_or("invalid date")?;
// Two tasks on the same resource at the same time.
let mut tasks = Vec::new();
let mut assignments = Vec::new();
for id in ["a", "b"] {
let mut task = TaskData::new(id);
task.start_date = Some(start);
task.duration = Some(2.0);
tasks.push(task);
assignments.push(AssignmentData {
id: None,
task: id.into(),
resource: "r1".into(),
value: 1.0,
offset: None,
duration: None,
});
}
let data = ProjectData {
tasks,
resources: vec![ResourceData { id: "r1".into(), capacity: None, calendar_id: None }],
assignments,
..Default::default()
};
let mut project = Project::default();
project.solve(Some(data), &SolveOptions::default())?;
// Only task "b" may move, picked by priority, without splits.
let options = LevelingOptions {
scope: Some(LevelingScope {
tasks: Some(vec!["b".into()]),
..Default::default()
}),
order: LevelingOrder::Priority,
allow_splits: false,
..Default::default()
};
let result = project.level(&options)?;
for update in &result.schedule.updates {
println!("{:?}: delay {:?}", update.id, update.leveling_delay);
}
Ok(())
}
```
## Related
- [`LevelingResult`]() - what a leveling run with these options returns
- [`LevelingScope`]() - the type of `scope`
- [`EvaluateOptions`]() - takes these options to score candidates at the leveled stage
- [Leveling Resources]() - walks through each option on a sample plan
- [Evaluating Alternatives]() - compares candidates after leveling