Struct re_ui::list_item::scope::LayoutStatistics

struct LayoutStatistics {
    max_desired_left_column_width: Option<f32>,
    is_action_button_used: bool,
    max_item_width: Option<f32>,
    property_content_max_width: Option<f32>,
}

Layout statistics accumulated during the frame that are used for next frame’s layout.

On frame n, statistics are gathered by the super::ListItemContent implementations and stored in this structure (via LayoutInfo methods). Then, it is saved in egui temporary memory against the scope id. On frame n+1, the accumulated values are used by list_item_scope to set up the LayoutInfo and the accumulator is reset to restart the process.

Here is an illustration of the layout statistics that are gathered:

│◀──────────────────────get_full_span()─────────────────────▶│
│                                                            │
│  ┌──left_x                                                 │
│  ▼                                                         │
│  │                       │                        │        │
│  ┌───────────────────────────────────────────┐             │
│  │                       │                   │    │        │
│  └───┬────────────────────────────────────┬──┘             │
│  │ ▼ │                   │                │       │        │
│      └───┬─────────────────────────┬──────┘                │
│  │       │               │         │              │        │
│          ├─────────────────────────┴────┐                  │
│  │     ▼ │               │              │         │        │
│          └───┬──────────────────────────┴─────────┐        │
│  │           │           │                        │        │
│              ├─────────────────────┬──────────────┘        │
│  │         ▶ │           │         │              │        │
│  ┌───────────┴─────────────────────┴──┐                    │
│  │                       │            │           │        │
│  └────────────────────────────────────┘                    │
│  │                       │                        │        │
│                                                            │
│  │◀──────────────────────▶ max_desired_left_column_width   │
│                                                            │
│  │◀───────────────max_item_width─────────────────▶│        │

Fields

max_desired_left_column_width: Option<f32>

Maximum desired column width.

The semantics are exactly the same as LayoutInfo’s left_column_width.

is_action_button_used: bool

Track whether any item uses the action button.

If so, space for a right-aligned gutter should be reserved.

max_item_width: Option<f32>

Max item width.

The width is calculated from LayoutInfo::left_x to the right edge of the item.

property_content_max_width: Option<f32>

PropertyContent only — max content width in the current scope.

This value is measured from left_x.

Implementations

impl LayoutStatistics

fn reset(ctx: &Context, scope_id: Id)

Reset the layout statistics to the default.

Should be called at the beginning of the frame.

fn read(ctx: &Context, scope_id: Id) -> Self

Read the saved accumulated value.

fn update(ctx: &Context, scope_id: Id, update: impl FnOnce(&mut Self))

Update the accumulator.

Used by LayoutInfo’s methods.

Trait Implementations

impl Clone for LayoutStatistics

fn clone(&self) -> LayoutStatistics

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LayoutStatistics

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LayoutStatistics

fn default() -> LayoutStatistics

Returns the “default value” for a type.